Imagine if you owned a farm and 250 anti-genetically modified food protesters decided to randomly plant thousands of organic potatoes on your field. I know this would both disturb and upset me; especially if I was growing organic beans!

That’s exactly what happened when a large group of protestors wishing to sabatoge a GM potato field accidently got the wrong farm. You can actually visit the protesters website at Mutatoes.Org. Their motto is, “stop the spuds”. Thanks to them, someone won’t be getting their beans.

Potato mutation is far more serious than you might imagine. As you can see from this story, 250 protesters were unable to tell the difference between the potatoes they were planting and the beans growing on the field. These protesters are people fighting for a cause they believe in, they know their potatoes better than anyone. Do you want to live in a world where mutation has caused potatoes to look so much like beans even knowledgeable protesters would mix them up? I don’t think so!

If only the knowledgeable protesters had listened to the poor farmer who was saying he grew beans then maybe my lawn would be a bit less dug up. Maybe this whole random potato plantation fad would never have happened. What a sad day it will be when people resort to communicating their problems and discussing them rather than playing the role of pawns for organizations with hidden agendas.

Thank you mutatoes, I think I will donate right now! I can see it’s money well spent!

Imagine if you owned a farm and 250 anti-genetically modified food protesters decided to randomly plant thousands of organic potatoes on your field. I know this would both disturb and upset me; especially if I was growing organic beans!

That’s exactly what happened when a large group of protestors wishing to sabatoge a GM potato field accidently got the wrong farm. You can actually visit the protesters website at Mutatoes.Org. Their motto is, “stop the spuds”. Thanks to them, someone won’t be getting their beans.

Potato mutation is far more serious than you might imagine. As you can see from this story, 250 protesters were unable to tell the difference between the potatoes they were planting and the beans growing on the field. These protesters are people fighting for a cause they believe in, they know their potatoes better than anyone. Do you want to live in a world where mutation has caused potatoes to look so much like beans even knowledgeable protesters would mix them up? I don’t think so!

If only the knowledgeable protesters had listened to the poor farmer who was saying he grew beans then maybe my lawn would be a bit less dug up. Maybe this whole random potato plantation fad would never have happened. What a sad day it will be when people resort to communicating their problems and discussing them rather than playing the role of pawns for organizations with hidden agendas.

Thank you mutatoes, I think I will donate right now! I can see it’s money well spent!

Take a moment to consider what something like this involves. It begins with people putting pressure on China to be more environmentally friendly. A meeting is called and someone suggests covering a hillside with green toxic paint to resolve the issue. The idea is approved and $60,600 is spent on putting the plan into action.

$60,600 worth of toxic paint could have bought 13,060 pounds of Perenniall Ryegrass seeds, enough to cover 1,632,343 square feet. The end result would also have been a green hillside, with plenty of seeds leftover to feed an entire fleet of remote controlled pigeons. $60,600 could also have been used to plant a fake forest with green cardboard trees. While this would also have been a waste of money, at least it would have been recyclable, not toxic.

Ironically, many people speculate that “officials of the surrounding Fumin county, whose office building faces the mountain, were trying to change the area’s feng shui - the ancient Chinese belief of harmonizing one’s physical environment for maximum health and financial benefit”. This means that government officials came to the conclusion that the best way to harmonize the environment for maximum health and financial benefit is by wasting money on destroying the environment even though the environment is necessary for good health and investing money wisely is necessary for financial benefit.

Protecting the environment and spray paint don’t go together. In fact, anytime you see a skull and crossbones image on a product you plan to dump on a hillside, chances are its a bad idea. That being said, don’t let politicians fool you. Protecting the environment and nuclear power also do not go together. A nuclear power plant may create less air pollutants, but that doesn’t change the fact that it’s a giant spray-paint can with millions of skull and crossbones all over it. As of 2000, Canada has 35,000 tonnes of highly radioactive nuclear waste, with nowhere to put it. With a radioactive half-life of 25,000 years, nuclear waste remains dangerous for 250,000 years (And these are just the problems we face when a nuclear power plant is working properly!). The damage from spray painting a mountain green will be gone long before then.

–

Sources:

http://www.cbc.ca/cp/Oddities/070214/K021404AU.html

http://www.davidsuzuki.org/Climate_Change/Energy/Nuclear.asp

Take a moment to consider what something like this involves. It begins with people putting pressure on China to be more environmentally friendly. A meeting is called and someone suggests covering a hillside with green toxic paint to resolve the issue. The idea is approved and $60,600 is spent on putting the plan into action.

$60,600 worth of toxic paint could have bought 13,060 pounds of Perenniall Ryegrass seeds, enough to cover 1,632,343 square feet. The end result would also have been a green hillside, with plenty of seeds leftover to feed an entire fleet of remote controlled pigeons. $60,600 could also have been used to plant a fake forest with green cardboard trees. While this would also have been a waste of money, at least it would have been recyclable, not toxic.

Ironically, many people speculate that “officials of the surrounding Fumin county, whose office building faces the mountain, were trying to change the area’s feng shui - the ancient Chinese belief of harmonizing one’s physical environment for maximum health and financial benefit”. This means that government officials came to the conclusion that the best way to harmonize the environment for maximum health and financial benefit is by wasting money on destroying the environment even though the environment is necessary for good health and investing money wisely is necessary for financial benefit.

Protecting the environment and spray paint don’t go together. In fact, anytime you see a skull and crossbones image on a product you plan to dump on a hillside, chances are its a bad idea. That being said, don’t let politicians fool you. Protecting the environment and nuclear power also do not go together. A nuclear power plant may create less air pollutants, but that doesn’t change the fact that it’s a giant spray-paint can with millions of skull and crossbones all over it. As of 2000, Canada has 35,000 tonnes of highly radioactive nuclear waste, with nowhere to put it. With a radioactive half-life of 25,000 years, nuclear waste remains dangerous for 250,000 years (And these are just the problems we face when a nuclear power plant is working properly!). The damage from spray painting a mountain green will be gone long before then.

–

Sources:

http://www.cbc.ca/cp/Oddities/070214/K021404AU.html

http://www.davidsuzuki.org/Climate_Change/Energy/Nuclear.asp

I ain’t afraid of no ghost!

I ain’t afraid of no ghost!

The U.S military has already tried creating remote controlled sharks and currently trains dolphins to search for mines.

“Scientists with the Robot Engineering Technology Research Center of east China’s Shandong University of Science and Technology say they implanted micro electrodes in the brain of a pigeon so they can command it to fly right or left or up or down.

The implants stimulated different areas of the pigeon’s brain according to signals sent by the scientists via computer, and forced the bird to comply with their commands.” - http://hackedgadgets.com/

Since we shouldn’t have to worry about a missile defense system against pigeons for another two or three years, I’ll focus the rest of this article on some of the benefits that could arise from this technology!

First of all, some non-military uses will be found for the birds. If Fedex can get their hands on some remote controlled pigeons I guarantee they will start using them to deliver mail just like owls do in Harry Potter. Sure, some animal rights activists will likely be against the idea of giving pigeons brain implants and using them to fly packages across the country and oversea, but imagine the savings! Thousands of workers could be laid off and replaced with pigeons who will be paid in grain. Also, think of the carbon savings! Switching to pigeons is a great way to reduce greenhouse gas emmissions and go green!

The technology will help clean up the streets. Most pigeons spend their days downtown panhandling and begging people for food. This technology will get the pigeons off the streets and into jobs seeing as many new employment possibilities will be available for the birds either as couriers or assassins.

Of course, this will inevitably lead to the development of remote controlled humans. If you think it’s impossible, guess again. The technology has obviously already been tested on many politicians who serve oil companies and large corporations rather than those who would elect them.

The U.S military has already tried creating remote controlled sharks and currently trains dolphins to search for mines.

“Scientists with the Robot Engineering Technology Research Center of east China’s Shandong University of Science and Technology say they implanted micro electrodes in the brain of a pigeon so they can command it to fly right or left or up or down.

The implants stimulated different areas of the pigeon’s brain according to signals sent by the scientists via computer, and forced the bird to comply with their commands.” - http://hackedgadgets.com/

Since we shouldn’t have to worry about a missile defense system against pigeons for another two or three years, I’ll focus the rest of this article on some of the benefits that could arise from this technology!

First of all, some non-military uses will be found for the birds. If Fedex can get their hands on some remote controlled pigeons I guarantee they will start using them to deliver mail just like owls do in Harry Potter. Sure, some animal rights activists will likely be against the idea of giving pigeons brain implants and using them to fly packages across the country and oversea, but imagine the savings! Thousands of workers could be laid off and replaced with pigeons who will be paid in grain. Also, think of the carbon savings! Switching to pigeons is a great way to reduce greenhouse gas emmissions and go green!

The technology will help clean up the streets. Most pigeons spend their days downtown panhandling and begging people for food. This technology will get the pigeons off the streets and into jobs seeing as many new employment possibilities will be available for the birds either as couriers or assassins.

Of course, this will inevitably lead to the development of remote controlled humans. If you think it’s impossible, guess again. The technology has obviously already been tested on many politicians who serve oil companies and large corporations rather than those who would elect them.

Farmers in Switzerland find that cannabis is a very affordable way to feed their cows who also seem happier upon consumption. The Agriculture Ministry however states that the active ingredient in cannabis, THC, can get into the milk and create a health risk. However, artificial growth hormones designed to increase milk production, when there is already an oversupply of milk, are perfectly safe.

If anyone should be allowed to get high, its the cows. We’ve taken all meaning and fun out of their lives while treating them as commodities to use and expend as we please. Cows do not live in the wild, we have enslaved their entire population. Despite this, they are not on any endangered species lists because we don’t view them as a creature any longer, but rather as a burgers or bags of milk. They have nothing going for them besides exploitation, just let the cows get high.

Of course, others will argue that we need to educate the young cows about the dangers of drugs and peer pressure. Do you want your cow to grow up and spend it’s life working at McDonald’s, being fed to people by employees making minimum wage?

Don’t think that cows are only being fed cannabis in Switzerland. These happy cow videos show American cows from California who are obviously also in a good mood. Do you want to make these cows sad? Of course not, man, thats messed up! Get out your plunger and pull the plug on the ban on feeding cows cannabis! THC does not accumulate in the food chain like poisonous mercury, yet fish have not been banned from living in the waters we have polluted and continue to make dangerous to our own health.

Farmers in Switzerland find that cannabis is a very affordable way to feed their cows who also seem happier upon consumption. The Agriculture Ministry however states that the active ingredient in cannabis, THC, can get into the milk and create a health risk. However, artificial growth hormones designed to increase milk production, when there is already an oversupply of milk, are perfectly safe.

If anyone should be allowed to get high, its the cows. We’ve taken all meaning and fun out of their lives while treating them as commodities to use and expend as we please. Cows do not live in the wild, we have enslaved their entire population. Despite this, they are not on any endangered species lists because we don’t view them as a creature any longer, but rather as a burgers or bags of milk. They have nothing going for them besides exploitation, just let the cows get high.

Of course, others will argue that we need to educate the young cows about the dangers of drugs and peer pressure. Do you want your cow to grow up and spend it’s life working at McDonald’s, being fed to people by employees making minimum wage?

Don’t think that cows are only being fed cannabis in Switzerland. These happy cow videos show American cows from California who are obviously also in a good mood. Do you want to make these cows sad? Of course not, man, thats messed up! Get out your plunger and pull the plug on the ban on feeding cows cannabis! THC does not accumulate in the food chain like poisonous mercury, yet fish have not been banned from living in the waters we have polluted and continue to make dangerous to our own health.

So how do squid waste their true anatomical potential? They stick their suction cups to whales! Granted I would do the same if given the opportunity, but that’s not the point. Next time I find myself in the middle of the ocean and I meet a giant squid I’m going to pray I have my plunger with me because I think it’s time we demonstrate why enslavement at the hands of humanity is a better alternative to gleefuly usage of suction cups on whales. Their heads are round and wet, creating the ideal location for a plunger to become stuck. The next time a 33-foot giant squid is found, you know what to do.

Don’t let these giant squid continue to steal media attention away from American Idol or Anna Nicole Smith. Do you want your children to see them on TV every night and then have squid-related nightmares? Do your part to ensure that the next time a giant squid shows up on TV, it has a plunger stuck to it’s head. The future of your child may very well be at stake…

So how do squid waste their true anatomical potential? They stick their suction cups to whales! Granted I would do the same if given the opportunity, but that’s not the point. Next time I find myself in the middle of the ocean and I meet a giant squid I’m going to pray I have my plunger with me because I think it’s time we demonstrate why enslavement at the hands of humanity is a better alternative to gleefuly usage of suction cups on whales. Their heads are round and wet, creating the ideal location for a plunger to become stuck. The next time a 33-foot giant squid is found, you know what to do.

Don’t let these giant squid continue to steal media attention away from American Idol or Anna Nicole Smith. Do you want your children to see them on TV every night and then have squid-related nightmares? Do your part to ensure that the next time a giant squid shows up on TV, it has a plunger stuck to it’s head. The future of your child may very well be at stake…

This box is extremely versatile. It can be used as a chair, or a bed. There is no reason to ever leave a box like this!

In fact, a strawberry flavored box like this also makes the perfect snack! Just chew chew chew until you can’t chew no more, then puke puke puke until there’s no more room on the floor! hehe! Don’t get the wrong idea, I’m not a messy cat, I cleanup all my mess later when I get hungry again. Cardboard is always easier to digest the second time around.

Tamra says, “Thank you Moe, Mindy and Karen Jo for the Awards!”

We think you are cool cats too!

This box is extremely versatile. It can be used as a chair, or a bed. There is no reason to ever leave a box like this!

In fact, a strawberry flavored box like this also makes the perfect snack! Just chew chew chew until you can’t chew no more, then puke puke puke until there’s no more room on the floor! hehe! Don’t get the wrong idea, I’m not a messy cat, I cleanup all my mess later when I get hungry again. Cardboard is always easier to digest the second time around.

Tamra says, “Thank you Moe, Mindy and Karen Jo for the Awards!”

We think you are cool cats too!

I was sure the servants would give-in, but after about a month, negotiations were still at a stale-mate. I decided to get out of my comfortable sun-bathing bed and use my secret weapon… irresistible cuteness!

My cuteness got me a lot of love and temptations, but still no internet access! I started to get depressed sitting around all day without my blog and all my cat friends…

So… I gave in, I caved, I stooped to an all-time low and agreed to let Griffin stick his giant head into my blog whenever he wants. I already accepted the fact that I would have to tolerate him in life, but looks like I’m officially stuck with him on my blog as well.

The last time I let Griffin write his own post, he wrote about puking up toilet paper… Hopefully my three month strike at least did some good by giving him enough time to lose some of his more disgusting habits so we never have to read about them!

Advertisement: Looble Network Find news, games, music, books, software, knowledge, cats and more!

I was sure the servants would give-in, but after about a month, negotiations were still at a stale-mate. I decided to get out of my comfortable sun-bathing bed and use my secret weapon… irresistible cuteness!

My cuteness got me a lot of love and temptations, but still no internet access! I started to get depressed sitting around all day without my blog and all my cat friends…

So… I gave in, I caved, I stooped to an all-time low and agreed to let Griffin stick his giant head into my blog whenever he wants. I already accepted the fact that I would have to tolerate him in life, but looks like I’m officially stuck with him on my blog as well.

The last time I let Griffin write his own post, he wrote about puking up toilet paper… Hopefully my three month strike at least did some good by giving him enough time to lose some of his more disgusting habits so we never have to read about them!

Advertisement: Looble Network Find news, games, music, books, software, knowledge, cats and more!

A Cat Condo is a perfect place to play some games! There are balls to whop and plenty of places to scratch and chew.

A Cat Condo is also a perfect place to wash. There are lots of furs and usually an extra tongue helping you!

A Cat Condo also serves well for naps. There isn’t much room but we always fit two.

In fact, there’s no reason to leave a Cat Condo except for food and to poo!

A Cat Condo is a perfect place to play some games! There are balls to whop and plenty of places to scratch and chew.

A Cat Condo is also a perfect place to wash. There are lots of furs and usually an extra tongue helping you!

A Cat Condo also serves well for naps. There isn’t much room but we always fit two.

In fact, there’s no reason to leave a Cat Condo except for food and to poo!

Battle City is a game requiring a great deal of strategy. To win you must drop the Orb item on the enemy cities Command Center. The Command Center is always heavily guarded so teamwork will be essential. You will need to bomb buildings and destroy defensive infrastructure using the weapons produced by the factories in your city.

You begin ranked as a Private and earn promotions based on how many points you gain. Work your way up to the rank of General by Orbing cities and blowing up tanks!

Another aspect of Battle City which makes the game very interesting is that you can play as either a Mayor or a Commando. If you are the Mayor, it is your job to build the city and hire Commandos. If you are a Commando, it is your job to defend your Mayors city and to attack enemy cities! A city can have only one mayor, so if parts of the base are destroyed in battle, only the mayor can make repairs. Each city can have a maximum of three commandos! As you can imagine, teamwork is an incredibly important aspect of BattleCity!

To download and play Battle City for free, visit:

http://battlecity.looble.com

Battle City is a game requiring a great deal of strategy. To win you must drop the Orb item on the enemy cities Command Center. The Command Center is always heavily guarded so teamwork will be essential. You will need to bomb buildings and destroy defensive infrastructure using the weapons produced by the factories in your city.

You begin ranked as a Private and earn promotions based on how many points you gain. Work your way up to the rank of General by Orbing cities and blowing up tanks!

Another aspect of Battle City which makes the game very interesting is that you can play as either a Mayor or a Commando. If you are the Mayor, it is your job to build the city and hire Commandos. If you are a Commando, it is your job to defend your Mayors city and to attack enemy cities! A city can have only one mayor, so if parts of the base are destroyed in battle, only the mayor can make repairs. Each city can have a maximum of three commandos! As you can imagine, teamwork is an incredibly important aspect of BattleCity!

To download and play Battle City for free, visit:

http://battlecity.looble.com

For the last week I’ve discovered how fun it is to eat Kleenex and unroll the toilet paper. Unfortunately, I’ve now also gotten hooked to eating the stuff! It’s just so wonderfully chewy!

As you may have already guessed… it wasn’t a furrball I puked up! It was more like half a roll of toilet paper which the servants then flushed down the toilet. The good news is that I must be using the toilet paper properly if the servants flushed it because thats what they do when they use it too.

I do find it odd that the humans weren’t more concerned when I puked… They seemed more interested in rolling all the toilet paper up again after I worked so hard to spread it nice and evenly across the floor. Tamra is right, they are definitely incompetent.

For the last week I’ve discovered how fun it is to eat Kleenex and unroll the toilet paper. Unfortunately, I’ve now also gotten hooked to eating the stuff! It’s just so wonderfully chewy!

As you may have already guessed… it wasn’t a furrball I puked up! It was more like half a roll of toilet paper which the servants then flushed down the toilet. The good news is that I must be using the toilet paper properly if the servants flushed it because thats what they do when they use it too.

I do find it odd that the humans weren’t more concerned when I puked… They seemed more interested in rolling all the toilet paper up again after I worked so hard to spread it nice and evenly across the floor. Tamra is right, they are definitely incompetent.

Today I was entrusted with the task of tying up a chicken. Simple as that may sound, a chicken is a formidable foe that should never be underestimated.

The first thing to do when asked to tie up a chicken is to desperately seek out advice from people who tie up chickens professionally. If you’re having trouble finding such a person, its because they’ve decided to use the fancy name of “trussing poultry” in order to describe their line of work.

One thing the professionals forget to mention is that you should always begin by making sure your chicken is dead. To do this, simply poke the chicken several times with your index finger and wait for a response. Feathers are not a vital organ so do not assume just because they are no longer present that your bird is dead. The bird I am presently cooking for instance used its slippery skin in order to attempt an escape when I picked it up. Approach your chicken with caution at all times.

Here is an article from the Food Network called Truss Poultry which provides step by step chicken trussing instructions for beginners like me:

How to Truss Poultry Instructions

How to Truss Poultry VIDEO!

The video is excellent unless, like me, you find yourself with a chicken that does not match the shape of the chicken in the video. If your chickens legs won’t cross, don’t force them too or the leg will fall right off…

So what do you do if your average chicken looks nothing like the big juicy ones that make it on TV? Improvise! The video suggests using a cord about three times the length of the chicken. I say, when in doubt, tie that bird up real good and use three feet of string if necessary! If it looks like an Egyptian mummy by the time it goes into the rotisserie, all the better! There’s no better way to preserve a chicken corpse.

The final step is actually cooking the chicken! Unfortunately I don’t think I’m quite qualified to offer assistance in this area yet as my mother f***** keeps catching on fire.

Today I was entrusted with the task of tying up a chicken. Simple as that may sound, a chicken is a formidable foe that should never be underestimated.

The first thing to do when asked to tie up a chicken is to desperately seek out advice from people who tie up chickens professionally. If you’re having trouble finding such a person, its because they’ve decided to use the fancy name of “trussing poultry” in order to describe their line of work.

One thing the professionals forget to mention is that you should always begin by making sure your chicken is dead. To do this, simply poke the chicken several times with your index finger and wait for a response. Feathers are not a vital organ so do not assume just because they are no longer present that your bird is dead. The bird I am presently cooking for instance used its slippery skin in order to attempt an escape when I picked it up. Approach your chicken with caution at all times.

Here is an article from the Food Network called Truss Poultry which provides step by step chicken trussing instructions for beginners like me:

How to Truss Poultry Instructions

How to Truss Poultry VIDEO!

The video is excellent unless, like me, you find yourself with a chicken that does not match the shape of the chicken in the video. If your chickens legs won’t cross, don’t force them too or the leg will fall right off…

So what do you do if your average chicken looks nothing like the big juicy ones that make it on TV? Improvise! The video suggests using a cord about three times the length of the chicken. I say, when in doubt, tie that bird up real good and use three feet of string if necessary! If it looks like an Egyptian mummy by the time it goes into the rotisserie, all the better! There’s no better way to preserve a chicken corpse.

The final step is actually cooking the chicken! Unfortunately I don’t think I’m quite qualified to offer assistance in this area yet as my mother f***** keeps catching on fire.

Recently the webhost Ipower migrated to a new hosting platform called Vdeck 3.0. In so doing, some of the changes have caused certain php powered applications to stop working. I believe this also affects a few other hosts such as Powweb and Ipowerweb, and any Ipower reseller hosts that just upgraded to vdeck 3.0.There are two ways to solve the problem. The best way would be to edit your php.ini file. However, out of fear of breaking all my working PHP applications, I decided to simply made a change in the applications not currently working to fix the issue.

The following is the solution I used.

I created a folder called “phpsessions” outside of my public_html folder. That is to say, if the following is the path to my public_html folder:

/home/users/blah/blah/public_html

then I created:

/home/users/blah/blah/phpsessions/

Next, open up your PHP application and look for the file where you start your sessions using “session_start();”

Look for:

Quote:

Replace with:

Quote:

Hopefully this solution will help others experiencing problems with their PHP applications!

Recently the webhost Ipower migrated to a new hosting platform called Vdeck 3.0. In so doing, some of the changes have caused certain php powered applications to stop working. I believe this also affects a few other hosts such as Powweb and Ipowerweb, and any Ipower reseller hosts that just upgraded to vdeck 3.0.There are two ways to solve the problem. The best way would be to edit your php.ini file. However, out of fear of breaking all my working PHP applications, I decided to simply made a change in the applications not currently working to fix the issue.

The following is the solution I used.

I created a folder called “phpsessions” outside of my public_html folder. That is to say, if the following is the path to my public_html folder:

/home/users/blah/blah/public_html

then I created:

/home/users/blah/blah/phpsessions/

Next, open up your PHP application and look for the file where you start your sessions using “session_start();”

Look for:

Quote:

Replace with:

Quote:

Hopefully this solution will help others experiencing problems with their PHP applications!

The SQLDebugger Windows user account is created when the SQL Debugger Registry2 DCOM server process (Sqldbreg2.exe) is registered. If you’ve installed SQL Server, then this process will be registered and therefore the SQLDebugger Windows user account will be created on your system. This account is used for connecting to a database server for debugging purposes. In such a case, you may actually want to keep the user account… But what if you haven’t even installed SQL Server… What the heck is SQLDebugger doing on your computer then?

Microsoft Visual Studio .NET applications use SQL Server Debugging to debug SQL Server stored procedures. So guess what that means? If you’ve installed Microsoft Visual Studio .NET, then you’ll have the SQLDebugger Windows user account created on your machine, even if you have no intentions of ever using it. While there is no danger in keeping the SQLDebugger account around, since it was created without your permission or without you even knowing about it and since it serves no purpose unless you are doing database debugging, JUST DELETE IT!

The SQLDebugger Windows user account is created when the SQL Debugger Registry2 DCOM server process (Sqldbreg2.exe) is registered. If you’ve installed SQL Server, then this process will be registered and therefore the SQLDebugger Windows user account will be created on your system. This account is used for connecting to a database server for debugging purposes. In such a case, you may actually want to keep the user account… But what if you haven’t even installed SQL Server… What the heck is SQLDebugger doing on your computer then?

Microsoft Visual Studio .NET applications use SQL Server Debugging to debug SQL Server stored procedures. So guess what that means? If you’ve installed Microsoft Visual Studio .NET, then you’ll have the SQLDebugger Windows user account created on your machine, even if you have no intentions of ever using it. While there is no danger in keeping the SQLDebugger account around, since it was created without your permission or without you even knowing about it and since it serves no purpose unless you are doing database debugging, JUST DELETE IT!

That being said, how the heck do you actually do it?

First, open up “viewforum_body.html”. If you are using the prosilver theme you can find this file here:

styles/prosilver/template/viewforum_body.html

Now search that file for the following text:

<!-- END postrow -->

Right before the line above, paste the following code into the file:

<!– IF postrow.S_FIRST_ROW –>
<div class=”post bg2″>
<div class=”inner”><span class=”corners-top”><span></span></span>

<div class=”postbody”>
<h3>Sponsor</h3>

<div class=”content” style=”text-align: center;”>
THE CODE FOR YOUR AD GOES HERE
</div>
</div>

<dl class=”postprofile” id=”profile0000″>
<dt>
<strong><u>Featured Sites</u></strong>
</dt>

<dd><a href=”http://www.looble.com”>Looble Network</a></dd>
<dd><a href=”http://www.free-games-center.com/”>Free Games Center</a></dd>
<dd><a href=”http://www.software-engineer-training.com/”>Software Engineer Training</a></dd>
<dd><a href=”http://flogger.looble.com/”>Flogger</a></dd>
<dd><a href=”http://www.writerdatabase.com/”>Writer Database</a></dd>
<dd><a href=”http://www.tamramaew.com/”>Tamra Maew</a></dd>
<dd><a href=”http://www.squishyrecords.com/”>Squishy Records</a></dd>
</dl>

<div class=”back2top”><a href=”#wrap” class=”top” title=”{L_BACK_TO_TOP}”>{L_BACK_TO_TOP}</a></div>
<span class=”corners-bottom”><span></span></span></div>
</div>
<hr class=”divider” />
<!– ENDIF –>

Make sure you place your ad code where I have bolded text above. Upload your new file and you are set! Out of love, we highly recommend you at least keep the Software Engineer Training link as one of your featured sites.

That being said, how the heck do you actually do it?

First, open up “viewforum_body.html”. If you are using the prosilver theme you can find this file here:

styles/prosilver/template/viewforum_body.html

Now search that file for the following text:

<!-- END postrow -->

Right before the line above, paste the following code into the file:

<!– IF postrow.S_FIRST_ROW –>
<div class=”post bg2″>
<div class=”inner”><span class=”corners-top”><span></span></span>

<div class=”postbody”>
<h3>Sponsor</h3>

<div class=”content” style=”text-align: center;”>
THE CODE FOR YOUR AD GOES HERE
</div>
</div>

<dl class=”postprofile” id=”profile0000″>
<dt>
<strong><u>Featured Sites</u></strong>
</dt>

<dd><a href=”http://www.looble.com”>Looble Network</a></dd>
<dd><a href=”http://www.free-games-center.com/”>Free Games Center</a></dd>
<dd><a href=”http://www.software-engineer-training.com/”>Software Engineer Training</a></dd>
<dd><a href=”http://flogger.looble.com/”>Flogger</a></dd>
<dd><a href=”http://www.writerdatabase.com/”>Writer Database</a></dd>
<dd><a href=”http://www.tamramaew.com/”>Tamra Maew</a></dd>
<dd><a href=”http://www.squishyrecords.com/”>Squishy Records</a></dd>
</dl>

<div class=”back2top”><a href=”#wrap” class=”top” title=”{L_BACK_TO_TOP}”>{L_BACK_TO_TOP}</a></div>
<span class=”corners-bottom”><span></span></span></div>
</div>
<hr class=”divider” />
<!– ENDIF –>

Make sure you place your ad code where I have bolded text above. Upload your new file and you are set! Out of love, we highly recommend you at least keep the Software Engineer Training link as one of your featured sites.

• Most current CVS features.Subversion is meant to be a better CVS, so it has most of CVS’s features. Generally, Subversion’s interface to a particular feature is similar to CVS’s, except where there’s a compelling reason to do otherwise.
• Directories, renames, and file meta-data are versioned.Lack of these features is one of the most common complaints against CVS. Subversion versions not only file contents and file existence, but also directories, copies, and renames. It also allows arbitrary metadata (”properties”) to be versioned along with any file or directory, and provides a mechanism for versioning the `execute’ permission flag on files.
• Commits are truly atomic.No part of a commit takes effect until the entire commit has succeeded. Revision numbers are per-commit, not per-file; log messages are attached to the revision, not stored redundantly as in CVS.
• Apache network server option, with WebDAV/DeltaV protocol.Subversion can use the HTTP-based WebDAV/DeltaV protocol for network communications, and the Apache web server to provide repository-side network service. This gives Subversion an advantage over CVS in interoperability, and provides various key features for free: authentication, wire compression, and basic repository browsing.
• Standalone server option.Subversion also offers a standalone server option using a custom protocol (not everyone wants to run Apache 2.x). The standalone server can run as an inetd service, or in daemon mode, and offers basic authentication and authorization. It can also be tunnelled over ssh.
• Branching and tagging are cheap (constant time) operationsThere is no reason for these operations to be expensive, so they aren’t.Branches and tags are both implemented in terms of an underlying “copy” operation. A copy takes up a small, constant amount of space. Any copy is a tag; and if you start committing on a copy, then it’s a branch as well. (This does away with CVS’s “branch-point tagging”, by removing the distinction that made branch-point tags necessary in the first place.)
• Natively client/server, layered library design Subversion is designed to be client/server from the beginning; thus avoiding some of the maintenance problems which have plagued CVS. The code is structured as a set of modules with well-defined interfaces, designed to be called by other applications.
• Client/server protocol sends diffs in both directionsThe network protocol uses bandwidth efficiently by transmitting diffs in both directions whenever possible (CVS sends diffs from server to client, but not client to server).
• Costs are proportional to change size, not data sizeIn general, the time required for a Subversion operation is proportional to the size of the changes resulting from that operation, not to the absolute size of the project in which the changes are taking place. This is a property of the Subversion repository model.
• Choice of database or plain-file repository implementationsRepositories can be created with either an embedded database back-end (BerkeleyDB) or with normal flat-file back-end, which uses a custom format.
• Versioning of symbolic linksUnix users can place symbolic links under version control. The links are recreated in Unix working copies, but not in win32 working copies.
• Efficient handling of binary filesSubversion is equally efficient on binary as on text files, because it uses a binary diffing algorithm to transmit and store successive revisions.
• Parseable outputAll output of the Subversion command-line client is carefully designed to be both human readable and automatically parseable; scriptability is a high priority.
• Localized messagesSubversion uses gettext() to display translated error, informational, and help messages, based on current locale settings.
• Repository mirroringSubversion supplies a utility, svnsync for synchronizing (via either push or pull) a read-only slave repository with a master repository.

For those using Windows, you should also install TortoiseSVN. TortoiseSVN will allow you to easily interact with Subversion directly through Windows Explorer. While viewing files saved on your system, if you right-click the screen you’ll see some new commands that will allow you to connect to your SVN repository and add or checkout files.

In order to use TortoiseSVN you need to first install Subversion and set up a Subversion repository where the program can keep the copies of the documents that you’ve checked in. Subversion will then only save differences between versions of files that you’re storing in its repository. This is much more efficient than making copies of all files and ending up with multiple copies of the same files.

To create a repository, at a command prompt issue the following command:

svnadmin create –fs-type=fsfs /data/SvnRepository

The directory specified above should be an empty directory!

The next step once everything is installed is to just play with it and figure out how to work it before using it on an actual project. Remember, always play before work!

• Most current CVS features.Subversion is meant to be a better CVS, so it has most of CVS’s features. Generally, Subversion’s interface to a particular feature is similar to CVS’s, except where there’s a compelling reason to do otherwise.
• Directories, renames, and file meta-data are versioned.Lack of these features is one of the most common complaints against CVS. Subversion versions not only file contents and file existence, but also directories, copies, and renames. It also allows arbitrary metadata (”properties”) to be versioned along with any file or directory, and provides a mechanism for versioning the `execute’ permission flag on files.
• Commits are truly atomic.No part of a commit takes effect until the entire commit has succeeded. Revision numbers are per-commit, not per-file; log messages are attached to the revision, not stored redundantly as in CVS.
• Apache network server option, with WebDAV/DeltaV protocol.Subversion can use the HTTP-based WebDAV/DeltaV protocol for network communications, and the Apache web server to provide repository-side network service. This gives Subversion an advantage over CVS in interoperability, and provides various key features for free: authentication, wire compression, and basic repository browsing.
• Standalone server option.Subversion also offers a standalone server option using a custom protocol (not everyone wants to run Apache 2.x). The standalone server can run as an inetd service, or in daemon mode, and offers basic authentication and authorization. It can also be tunnelled over ssh.
• Branching and tagging are cheap (constant time) operationsThere is no reason for these operations to be expensive, so they aren’t.Branches and tags are both implemented in terms of an underlying “copy” operation. A copy takes up a small, constant amount of space. Any copy is a tag; and if you start committing on a copy, then it’s a branch as well. (This does away with CVS’s “branch-point tagging”, by removing the distinction that made branch-point tags necessary in the first place.)
• Natively client/server, layered library design Subversion is designed to be client/server from the beginning; thus avoiding some of the maintenance problems which have plagued CVS. The code is structured as a set of modules with well-defined interfaces, designed to be called by other applications.
• Client/server protocol sends diffs in both directionsThe network protocol uses bandwidth efficiently by transmitting diffs in both directions whenever possible (CVS sends diffs from server to client, but not client to server).
• Costs are proportional to change size, not data sizeIn general, the time required for a Subversion operation is proportional to the size of the changes resulting from that operation, not to the absolute size of the project in which the changes are taking place. This is a property of the Subversion repository model.
• Choice of database or plain-file repository implementationsRepositories can be created with either an embedded database back-end (BerkeleyDB) or with normal flat-file back-end, which uses a custom format.
• Versioning of symbolic linksUnix users can place symbolic links under version control. The links are recreated in Unix working copies, but not in win32 working copies.
• Efficient handling of binary filesSubversion is equally efficient on binary as on text files, because it uses a binary diffing algorithm to transmit and store successive revisions.
• Parseable outputAll output of the Subversion command-line client is carefully designed to be both human readable and automatically parseable; scriptability is a high priority.
• Localized messagesSubversion uses gettext() to display translated error, informational, and help messages, based on current locale settings.
• Repository mirroringSubversion supplies a utility, svnsync for synchronizing (via either push or pull) a read-only slave repository with a master repository.

For those using Windows, you should also install TortoiseSVN. TortoiseSVN will allow you to easily interact with Subversion directly through Windows Explorer. While viewing files saved on your system, if you right-click the screen you’ll see some new commands that will allow you to connect to your SVN repository and add or checkout files.

In order to use TortoiseSVN you need to first install Subversion and set up a Subversion repository where the program can keep the copies of the documents that you’ve checked in. Subversion will then only save differences between versions of files that you’re storing in its repository. This is much more efficient than making copies of all files and ending up with multiple copies of the same files.

To create a repository, at a command prompt issue the following command:

svnadmin create –fs-type=fsfs /data/SvnRepository

The directory specified above should be an empty directory!

The next step once everything is installed is to just play with it and figure out how to work it before using it on an actual project. Remember, always play before work!

In case you aren’t familiar with The Naming of Cats, in the Old Possum’s Book of Practical Cats, by T.S. Eliot, we all have three names! So, in this meme, you must link to the originator of the meme (Tara and Kavan), list the following rules, and then tell us:

1. The name that the family uses daily (such as Peter, Agustus, Alonzo, or James)
2. The name that is particular, a name thats peculiar, and more dignified (such as Munkustrap, Quaxo, or Coricopat)

3. What you are doing when you are thinking of the name that only you know, and will never confess (when engaged in rapt contemplation), that deep and inscrutable singular name

Then tag three cats to give their three names.

Here are my three names:

1. Tamra… or Tamra Maew if im being bad!
2. HoneyBunnyBites
3. Wondering what Griffins ears taste like with mayonnaise… mmm mayonnaise!

and here are Griffins:

1. Griffin
2. MonkeyClawsClimb
3. Developing a master plan for my next attack on Tamra’s tail!

I’ll tag Storm the furry fighter, Hendrix and TT!

Also, I’ve got a role in CCSI III which airs this weekend! Be sure to check it out at Sassy’s Blog!

In case you aren’t familiar with The Naming of Cats, in the Old Possum’s Book of Practical Cats, by T.S. Eliot, we all have three names! So, in this meme, you must link to the originator of the meme (Tara and Kavan), list the following rules, and then tell us:

1. The name that the family uses daily (such as Peter, Agustus, Alonzo, or James)
2. The name that is particular, a name thats peculiar, and more dignified (such as Munkustrap, Quaxo, or Coricopat)

3. What you are doing when you are thinking of the name that only you know, and will never confess (when engaged in rapt contemplation), that deep and inscrutable singular name

Then tag three cats to give their three names.

Here are my three names:

1. Tamra… or Tamra Maew if im being bad!
2. HoneyBunnyBites
3. Wondering what Griffins ears taste like with mayonnaise… mmm mayonnaise!

and here are Griffins:

1. Griffin
2. MonkeyClawsClimb
3. Developing a master plan for my next attack on Tamra’s tail!

I’ll tag Storm the furry fighter, Hendrix and TT!

Also, I’ve got a role in CCSI III which airs this weekend! Be sure to check it out at Sassy’s Blog!

Today is my birthday! I think I’ve come a long way since I posted that first picture of myself back in June 2007… In fact, now that I think about it…

… it all started on a sad evening near the end of June when my furr brother and sister left with their new slaves. It was dark outside, pouring rain, with all happiness in the world being washed away by the tears running down my face when suddenly a loud buzzing noise filled the room. Two very incompetent looking humans walked in and one began to rub me against his face while sniffing me. I felt my little heart bounce up and down with joy when they returned to take me home, even though I knew I’d have a lot of training to do with these two.

Thankfully my servants knew the basics and immediately provided me with mice to play with. Still, there were times when I needed to discipline them or remind them that my beauty was not to be ignored. When it comes to food, they are still incompetent to this very day, forcing me to steal coffee or alcoholic beverages on a daily basis.

Sleeping arrangements have always been adequate and in fact I even claimed my own chair in the house! The humans also encouraged my artistic talents by helping me get on the big YouTube Screen with my Halloween Movie. Still, if you look at my List of Favorite Things, the humans often try to prevent me from enjoying them and thus require further disciplining.

As I continue to age I also continue to acquire more and more wisdom. I’ve therefore diversified my disciplining techniques to also include punishment in the form of mischief. Climbing the screen, knocking down clothes in the closet, or shredding the chair, are just some of my better ideas. If they wish to retain my affections, they have no choice but to learn from their mistakes and reward my mischief with gifts, such as when I got my collar!

If discipling my human servants wasn’t enough to keep me busy for an entire year, there was also the matter of the alien invasion I had to take care of… I also had to constantly keep a very close eye on the pickle monster in my house… You would think after making these sacrifices on my part for the betterment of humanity and my household I would be rewarded, but again my servants went and proved their incompetence by going and brining home Griffin…

All in all, while I made some progress in training my servants in my first year, I still have a lot of work left ahead of me in the next year! With the way Griffin has been Growing Like a Weed, he may soon prove to be a formidable ally in my quest to train the incompetent servants. Of course, I may have my work cut out for me training him as well…

Here’s my furr Mom and Dad wishing me a Happy Birthday!

I’d love to stay and chat some more but Griffin say’s he wants to show me something in the office. He says he has a plan for mischief he wans to give me for my birthday that involves stealing clothes pins…! The only thing that could beat that is if the servants bring me an empty box tonight for me to play in!

Today is my birthday! I think I’ve come a long way since I posted that first picture of myself back in June 2007… In fact, now that I think about it…

… it all started on a sad evening near the end of June when my furr brother and sister left with their new slaves. It was dark outside, pouring rain, with all happiness in the world being washed away by the tears running down my face when suddenly a loud buzzing noise filled the room. Two very incompetent looking humans walked in and one began to rub me against his face while sniffing me. I felt my little heart bounce up and down with joy when they returned to take me home, even though I knew I’d have a lot of training to do with these two.

Thankfully my servants knew the basics and immediately provided me with mice to play with. Still, there were times when I needed to discipline them or remind them that my beauty was not to be ignored. When it comes to food, they are still incompetent to this very day, forcing me to steal coffee or alcoholic beverages on a daily basis.

Sleeping arrangements have always been adequate and in fact I even claimed my own chair in the house! The humans also encouraged my artistic talents by helping me get on the big YouTube Screen with my Halloween Movie. Still, if you look at my List of Favorite Things, the humans often try to prevent me from enjoying them and thus require further disciplining.

As I continue to age I also continue to acquire more and more wisdom. I’ve therefore diversified my disciplining techniques to also include punishment in the form of mischief. Climbing the screen, knocking down clothes in the closet, or shredding the chair, are just some of my better ideas. If they wish to retain my affections, they have no choice but to learn from their mistakes and reward my mischief with gifts, such as when I got my collar!

If discipling my human servants wasn’t enough to keep me busy for an entire year, there was also the matter of the alien invasion I had to take care of… I also had to constantly keep a very close eye on the pickle monster in my house… You would think after making these sacrifices on my part for the betterment of humanity and my household I would be rewarded, but again my servants went and proved their incompetence by going and brining home Griffin…

All in all, while I made some progress in training my servants in my first year, I still have a lot of work left ahead of me in the next year! With the way Griffin has been Growing Like a Weed, he may soon prove to be a formidable ally in my quest to train the incompetent servants. Of course, I may have my work cut out for me training him as well…

Here’s my furr Mom and Dad wishing me a Happy Birthday!

I’d love to stay and chat some more but Griffin say’s he wants to show me something in the office. He says he has a plan for mischief he wans to give me for my birthday that involves stealing clothes pins…! The only thing that could beat that is if the servants bring me an empty box tonight for me to play in!

Go habs go! Go habs go!

While watching the game, I decided to ask Tamra what would happen if we cheered for the other team? Right now they are playing the Flyers, and I have recently found birds and flies to be interesting since the start of Spring.

I suggest you all cheer for the Montreal Canadiens. I found out the hard way what would happen

As you can see, the referee finally had to separate us! The ref warned that if we kept roughing we would get a 2 minute penalty in the PTU!

Meezer Rule: If you’re gonna rough up the opponent, make sure you aren’t sitting on the referee’s lap or you’ll always get caught!

Advertisement: WriterDatabase.com Submit your articles to increase your incoming traffic and page rank!

Go habs go! Go habs go!

While watching the game, I decided to ask Tamra what would happen if we cheered for the other team? Right now they are playing the Flyers, and I have recently found birds and flies to be interesting since the start of Spring.

I suggest you all cheer for the Montreal Canadiens. I found out the hard way what would happen

As you can see, the referee finally had to separate us! The ref warned that if we kept roughing we would get a 2 minute penalty in the PTU!

Meezer Rule: If you’re gonna rough up the opponent, make sure you aren’t sitting on the referee’s lap or you’ll always get caught!

Advertisement: WriterDatabase.com Submit your articles to increase your incoming traffic and page rank!

Meezer Rule: When your brother is a fatso, sleep with one eye open to protect your beautiful furrs!

Here are some pictures showing his alarming size increase…! Did I mention he even steals my food?

Go habs go!

Also, thank you Karl from The Cat Realm for the Valued Friend Award!

Advertisement: Looble Network Find news, games, music, books, software, knowledge, cats and more!

Meezer Rule: When your brother is a fatso, sleep with one eye open to protect your beautiful furrs!

Here are some pictures showing his alarming size increase…! Did I mention he even steals my food?

Go habs go!

Also, thank you Karl from The Cat Realm for the Valued Friend Award!

Advertisement: Looble Network Find news, games, music, books, software, knowledge, cats and more!

While I was initially uncertain of his true intentions when he first invaded my territory, I’ve come to realize he is nothing more than a tiny goof ball with no evident purpose in any of his actions. For the most part, he will just wander around aimlessly, bumping into things, purring and licking peoples faces. Given the proper training from his older, much more beautiful and smarter sister, he could perhaps become a useful tool. One day, he may very well get to sit by my side on the servants desk while we plot evil mischief to punish the servants for their constant incompetence.

Of course, Griffin still can’t quite reach the desk yet! In fact, he got to try on his collar recently and it can still slip right off his head!

For such a tiny little fellow, he sure can produce a lot of heat when he naps! The servants think it’s cute when I snuggle with him, but my taking advantage of his heat for personal comfort should not be misconstrued as appreciation for his presence. For the time being, I will continue to tolerate him with the hope that he should prove useful in the future.

While I was initially uncertain of his true intentions when he first invaded my territory, I’ve come to realize he is nothing more than a tiny goof ball with no evident purpose in any of his actions. For the most part, he will just wander around aimlessly, bumping into things, purring and licking peoples faces. Given the proper training from his older, much more beautiful and smarter sister, he could perhaps become a useful tool. One day, he may very well get to sit by my side on the servants desk while we plot evil mischief to punish the servants for their constant incompetence.

Of course, Griffin still can’t quite reach the desk yet! In fact, he got to try on his collar recently and it can still slip right off his head!

For such a tiny little fellow, he sure can produce a lot of heat when he naps! The servants think it’s cute when I snuggle with him, but my taking advantage of his heat for personal comfort should not be misconstrued as appreciation for his presence. For the time being, I will continue to tolerate him with the hope that he should prove useful in the future.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.

Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.

• Armagetron (http://armagetronad.net/)
  • Forum
    
  • Armagetron Wiki
    

• Free Orion (http://www.freeorion.org/index.php/Main_Page

• FreeCiv (http://freeciv.wikia.com/wiki/Main_Page)

• jRisk (http://risk.sourceforge.net/) and TEG (http://teg.sourceforge.net/)

• vbGore (http://www.vbgore.com/)

• Armagetron (http://armagetronad.net/)
  • Forum
    
  • Armagetron Wiki
    

• Free Orion (http://www.freeorion.org/index.php/Main_Page

• FreeCiv (http://freeciv.wikia.com/wiki/Main_Page)

• jRisk (http://risk.sourceforge.net/) and TEG (http://teg.sourceforge.net/)

• vbGore (http://www.vbgore.com/)

http://www.uniball-central.net/

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.

Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.

http://www.uniball-central.net/

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Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.

Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.

Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.

Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.

Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.

Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.

If you’re interested in working with the code and creating your own SimCity game, visit the Micropolis Wiki Page. All the details you need in order to get started are listed on this Wiki page.

If you’d like additional help getting started, check out this great series by Bil Simser.

Don Hopkins is currently translating the source code to C++. This C++ version, known as Micropolis Core, is still a work in progress. The game itself is not yet playable, but you can scroll and zoom around the map. Visit the Micropolis project page on Google Code to see the latest news or to download the latest code for this version.

If you’re interested in working with the code and creating your own SimCity game, visit the Micropolis Wiki Page. All the details you need in order to get started are listed on this Wiki page.

If you’d like additional help getting started, check out this great series by Bil Simser.

Don Hopkins is currently translating the source code to C++. This C++ version, known as Micropolis Core, is still a work in progress. The game itself is not yet playable, but you can scroll and zoom around the map. Visit the Micropolis project page on Google Code to see the latest news or to download the latest code for this version.

While waiting for this sock rockin’ website to be completed, check out the other website I currently write on a similar topic:

Web Dev Notes 

While waiting for this sock rockin’ website to be completed, check out the other website I currently write on a similar topic:

Web Dev Notes 

Reasons for TCP

The Internet Protocol (IP) works by exchanging groups of information called packets. Packets are short sequences of bytes consisting of a header and a body. The header describes the packet’s destination, which routers on the Internet use to pass the packet along, in generally the right direction, until it arrives at its final destination. The body contains the application data.

In cases of congestion, the IP can discard packets, and, for efficiency reasons, two consecutive packets on the internet can take different routes to the destination. Then, the packets can arrive at the destination in the wrong order.

The TCP software libraries use the IP and provides a simpler interface to applications by hiding most of the underlying packet structures, rearranging out-of-order packets, minimizing network congestion, and re-transmitting discarded packets. Thus, TCP very significantly simplifies the task of writing network applications.

Source: http://en.wikipedia.org/wiki/Transmission_Control_Protocol

Applicability of TCP

TCP is used extensively by many of the Internet’s most popular application protocols and resulting applications, including the World Wide Web, E-mail, File Transfer Protocol, Secure Shell, and some streaming media applications.However, because TCP is optimized for accurate delivery rather than timely delivery, TCP sometimes incurs long delays while waiting for out-of-order messages or retransmissions of lost messages, and it is not particularly suitable for real-time applications such as Voice over IP. For such applications, protocols like the Real-time Transport Protocol (RTP) running over the User Datagram Protocol (UDP) are usually recommended instead.

Source: http://en.wikipedia.org/wiki/Transmission_Control_Protocol

Using TCP

Using TCP, applications on networked hosts can create connections to one another, over which they can exchange streams of data using stream sockets. TCP also distinguishes data for multiple connections by concurrent applications (e.g., Web server and e-mail server) running on the same host.

In the Internet protocol suite, TCP is the intermediate layer between the Internet Protocol (IP) below it, and an application above it. Applications often need reliable pipe-like connections to each other, whereas the Internet Protocol does not provide such streams, but rather only best effort delivery (i.e., unreliable packets). TCP does the task of the transport layer in the simplified OSI model of computer networks. The other main transport-level Internet protocols are UDP and SCTP.

Applications send streams of octets (8-bit bytes) to TCP for delivery through the network, and TCP divides the byte stream into appropriately sized segments (usually delineated by the maximum transmission unit (MTU) size of the data link layer of the network to which the computer is attached). TCP then passes the resulting packets to the Internet Protocol, for delivery through a network to the TCP module of the entity at the other end. TCP checks to make sure that no packets are lost by giving each packet a sequence number, which is also used to make sure that the data is delivered to the entity at the other end in the correct order. The TCP module at the far end sends back an acknowledgment for packets which have been successfully received; a timer at the sending TCP will cause a timeout if an acknowledgment is not received within a reasonable round-trip time (or RTT), and the (presumably) lost data will then be re-transmitted. The TCP checks that no bytes are corrupted by using a checksum; one is computed at the sender for each block of data before it is sent, and checked at the receiver.

Source: http://en.wikipedia.org/wiki/Transmission_Control_Protocol

Services Provided by TCP

TCP provides more services than UDP because it is connection oriented whereas UDP is not. TCP allows for point-to-point communication, adressing, multiplexing, demultiplexing, reliability, full-duplex communication, flow control and congestion control.

The reason the whole internet can actually even work is in part thanks to the design of TCP which can dynamically adapt to different properties such as bandwidth, delay and packet loss as well as recover from errors.

TCP splits user data into pieces no larger than 64K bytes and then sends each of these pieces as separate IP datagrams. When these IP datagrams are received at the destination, TCP reconstructs the original byte stream. In order to establish the connection between the sender and destination, sockets are used. Sockets are really just the combination of an IP address and a port number.

A connection is established between two computers using what is called a “three-way handshake”.

The originator (you, hopefully) sends an initial packet called a “SYN” to establish communication and “synchronize” sequence numbers in counting bytes of data which will be exchanged. The destination then sends a “SYN/ACK” which again “synchronizes” his byte count with the originator and acknowledges the initial packet. The originator then returns an “ACK” which acknowledges the packet the destination just sent him. The connection is now “OPEN” and ongoing communication between the originator and the destination are permitted until one of them issues a “FIN” packet, or a “RST” packet, or the connection times out. All the protocols of the Internet which need “connections” are built on the TCP protocol. The “three way handshake” establishes the communication. Much like you picking up your phone, getting a dial tone, dialing the number, hearing ringing, and then the other party saying “hello” or “mushi mushi.”

Source: http://www.pccitizen.com/threewayhandshake.htm

TCP also closes a connection gracefully. Upon closing, the last data segment is followed by a FIN which also has a sequence number associated with it. This way, if the FIN arrives before all segments are received, it will wait for the expected data before closing.

The biggest source of errors in message transmission come from segments damaged in transmission or segments which entirely fail to arrive. The sender obviously does not know if the message sent has been received at the destination or not so it is necessary in TCP for the receiver to acknowledge receipt. In UDP, since reliability is not a concern and since it is a connectionless protocol, this acknowledgment does not occur.

Of course, we need to switch our point of view as soon as the destination sends an acknowledgment because at this point the receiver is acting as a sender. It is therefore entirely possible that the acknowledgment message gets lost or damaged in transmission as well. Therefore, it is necessary to have timers on both the sender and receiver which trigger a re-send after a certain amount of time to make sure the application does not end up in a dead-lock state where both sides are waiting to receive something from the other.

What is the value of the timer? It is possible to have a fixed timer or to use an adaptive scheme. Depending on the network, different value will be more appropriate for different situations and even for a given network, the perfect value can change depending on the amount of traffic on the network. If the timer value is set to be too short, re-transmission will clog the network causing further delay and therefore leading to even more ACK’s being sent! This can therefore become a rather messy situation. Of course, if the timer is set too high, performance will suffer because the delay before re-transmission leads to the application sitting and waiting. Therefore, the ideal timer will have some functionality to be aware of network conditions and then use this information in order to dynamically increase or decrease the timer.

Another problem thatmust be dealt with arises from the fact that TCP re-transmits messages as stated above in order to guarantee transmission. Since messages and ACK’s may be re-transmitted, we suddenly end up in a situation where it is possible for the destination to receive duplicates. For example, imagine that the receiver sends an ACK in order to confirm receipt of a message but high network traffic causes this ACK to travel slowly. Meanwhile the sender is waiting for the ACK when suddenly it’s timer expires and it therefore decides to re-transmit the message. Right after sending the message the ACK might finally arrive, however the duplicate has already been sent! The sender will now not send the message a third time because the ACK was received but the receiver will need to deal with the duplicate message that will soon be arriving! In order to deal with duplicates, the receiver can use the sequence number to determine if the message has already been received. However, for this to work correctly we are assuming that the sequence number space is large enough that it does not restart within the life-span of a packet. In a nutshell, the sequence space is a fixed number. When a connection is established the first message always starts at the first sequence number and eventually, if the connections has been open long enough and many messages have been sent, eventually the last available sequence number is reached. At this point, the next message sent will start back at the first sequence number. Therefore, it is possible for two messages with the same sequence number to exist and not be duplicates!

Congestion is caused when too much traffic is flowing through a network that individual messages are delayed because messages are arriving more quickly than can be processed. When this occurs, routers will begin dropping packets, starting with those it feels are of a lower priority. Therefore, as congestion occurs, time-outs start to happen causing messages to be re-transmitted. This of course is done in order to make sure the message does in fact arrive, but for a system experiencing congestion, this reliability feature imply contributes to the congestion. TCP congestion control handles this by estimating the round trip delay by observing patterns of delay and then setting the timer so a value greater than the time estimated. The timer is set higher in order to account for round trip time variance.

RTO - Re-transmission timeout

As discussed above, a timer is set on both the sender and receiver upon transmitting a message. If an acknowledgment is not received before this timer expires then a time-out occurs which triggers the re-transmission of the message. Using a fixed timer is not a good idea because the main cause for such occurring is congestion. If congestion occurs on your network and you message times-out, if you re-transmit the same message and keep the timer at the same value, chances are the message will time-out yet again if network conditions have not improved. Therefore, if we assume congestion is the culprit, it is important to give the message some extra time upon re-transmission in order to see if this extra time is enough for it to reach the destination and be acknowledged. The act of increasing the timer each time a message is re-transmitted is referred to as re-transmission timeout backoff. The most common type of RTO backoff is binary exponential backoff which takes the current timer value and multiplies it by two each time a message is re-transmitted.

Another issue that is important to consider is with respect to shrinking the timer back down. Re-transmitted messages should never be used as a guage when measuring RTT (round trip time) because the acknowledgment received could actually be for the first message transmitted and not for the re-transmitted one! Therefore, the RTO backoff should continue to be used until an ACK arrives for a message that has not been re-transmitted. At this point, it is up to the designer to decide how to implement the system. The timer can be left constant for a given amount of time and then upon receiving a certain number of messages without needing to re-transmit, the timer value can be divided by two in order to shrink it back down, meaning that perhaps network conditions have improved.

Window Management

Slow-start is part of the congestion control used in TCP in order to avoid sending more data than the network is able to handle.

Slow-Start Algorithm

A slow-start algorithm consists of two distinct phases: the exponential growth phase, and the linear growth phase.

During the exponential growth phase, Slow-start works by increasing the TCP congestion window each time the acknowledgment is received. It increases the window size by number of segments acknowledged. This happens until either an acknowledgment is not received for some segment or a predetermined threshold value is reached. If a loss event occurs, TCP assumes this it is due to network congestion and takes steps to reduce the offered load on the network. Once a loss event has occurred or the threshold has been reached, TCP enters the linear growth (congestion avoidance) phase. At this point, the window is increased by 1 segment for each RTT. This happens until a loss event occurs.

Although the strategy is referred to as “slow-start”, its congestion window growth is quite aggressive.

The algorithm begins in the exponential growth phase initially with a congestion window size (cwnd) of 1 or 2 segments and increases it by 1 Segment Size (SS) for each ACK received. This behavior effectively doubles the window size each round trip of the network. This behavior continues until the cwnd reaches the size of the receivers advertised window or until a loss occurs.

When a loss occurs half of the current cwnd is saved as a Slow Start Threshold (SSThresh) and slow start begins again from its initial cwnd. Once the cwnd reaches the SSThresh TCP goes into congestion avoidance mode where each ACK increases the cwnd by SS*SS/cwnd. This results in a linear increase of the cwnd.

Source: http://en.wikipedia.org/wiki/Slow-start

TCP Data Transfer

When a TCP connection is established, a stream of bytes is what will actually be sent between communicating entities, not messages. Messages themselves can be sent by any combination of pieces which give a total of 2048 bytes. Therefore, is you wish to send 4 messages each of which are 512 bytes, TCP might not actually send your message right away if it is set to wait for a total of 2048 bytes before transmitting. If this is the case, it will not send your 512 byte messages until 4 of these such messages are ready to be sent. TCP could also instead be set to send 2 pieces each of size 1024 bytes, and therefore only 2 messages need be ready in order to be transmitted. The important thing to understand is that a message being ready to be sent does not mean that this message itself is sent, but rather pieces of bytes which are then re-combined in order to re-create the message. Also, its important to note that TCP may decide to wait with your message and collect more data before transmitting. Certain flags can be used in order to request no delay.

TCP Header

Source: http://www.visi.com/~mjb/Drawings/

TCP Header Fields

Source and destination port - 16 bit address corresponding to the port which is associated with the value defined in the socket used to establish the connection.

Sequence and acknowledgment numbers - These are both 32 bit numbers which are used to help ensure reliable delivery of messages. Every TCP packet send has a sequence number associated with it and the acknowledgment is used to communicate to the other entity which sequence number is expected next.

URG - this will be set to 1 if the urgent pointer is used. The pointer will indicate an offset from the current sequence number which informs the receiver at which point the urgent data ends.

ACK - set to 1 to indicate the acknowledgment is valid.

PSH - set to 1 to indicate pushed data. Pushed data is data that the sender force-delivered without waiting for the buffer to fill.

RST - set to 1 to indicate a reset. This can be used to reject a connection or to refuse an invalid segment. It can also be used if the host has become confused for whatever reason and therefore would like to re-establish the connection.

SYN - used in order to establish a connection. If SYN = 1 an ACK = 0 then a connection request is in progress. If SYN = 1 and ACK = 1 then a connection acceptance is in progress.

FIN - this is set to 1 in order to indicate the end of user data and to therefore close the connection. As discussed earlier, data may still be received after the FIN because the FIN also has a sequence number associated with it and it is possible that messages with an earlier sequence number arrive after the FIN which should actually be processed and which are.

TCP Error Checking

Error checking is accomplished by using the checksum field available in the TCP header. The receiver performs a calculation on the checksum field and the user data and if the result is not 0, this indicates that there is an error somewhere.

TCP Options

The options field available in the TCP header allows for extra features to be used or certain settings to be set. Below are some example:

- During connection, this field is used for connecting entities to negotiate an acceptable maximum segment size.

- Since network speeds have increased dramatically since TCP was first introduced, 16 bits used for sequence numbers is actually no longer enough and the problem of incorrect duplicate detection becomes a major concern. It is therefor possible to also use the options field to allow for an increase in the number of available sequence numbers from 2^16 to 2^32.

- The options field can also be used to include a time-stamp which can then be used in order to determine round trip time, information that can then be used for congestion control.

Additional Time Issues

Given all of the information presented above, there are some other issues to consider with respect to the timer. As mentioned a persistence timer is essential in order to avoid deadlock situations. This timer will expire and cause the last message to be re-transmitted if no acknowledgment is received in a timely fashion. When using congestion control, it is possible for the available window size to go down to 0, which causes the sender to stop sending messages temporarily until it is notified that there is space again in the window. Therefore, even in this situation it is still important to occasionally have a timer expire causing the sender to ask the receiver if it has space in its window. This is necessary because imagine if an acknowledgment sent increasing the window size is lost, the system would be stuck waiting forever!

Of course, the above assumes that the problem is due to congestion. It is possible that there is no connection but that the entity you are communicating with is no longer available or has gone offline. Is is therefore also important not to continue trying to send messages to this user forever, but to instead also maintain a keep-alive timer which will occasionally cause a message to be sent to the receiver asking, “are you still there?”. If no response is received, the connection should be terminated so resources are not wasted sending messages to an entity which is no longer available to receive these messages.

Reasons for TCP

The Internet Protocol (IP) works by exchanging groups of information called packets. Packets are short sequences of bytes consisting of a header and a body. The header describes the packet’s destination, which routers on the Internet use to pass the packet along, in generally the right direction, until it arrives at its final destination. The body contains the application data.

In cases of congestion, the IP can discard packets, and, for efficiency reasons, two consecutive packets on the internet can take different routes to the destination. Then, the packets can arrive at the destination in the wrong order.

The TCP software libraries use the IP and provides a simpler interface to applications by hiding most of the underlying packet structures, rearranging out-of-order packets, minimizing network congestion, and re-transmitting discarded packets. Thus, TCP very significantly simplifies the task of writing network applications.

Source: http://en.wikipedia.org/wiki/Transmission_Control_Protocol

Applicability of TCP

TCP is used extensively by many of the Internet’s most popular application protocols and resulting applications, including the World Wide Web, E-mail, File Transfer Protocol, Secure Shell, and some streaming media applications.However, because TCP is optimized for accurate delivery rather than timely delivery, TCP sometimes incurs long delays while waiting for out-of-order messages or retransmissions of lost messages, and it is not particularly suitable for real-time applications such as Voice over IP. For such applications, protocols like the Real-time Transport Protocol (RTP) running over the User Datagram Protocol (UDP) are usually recommended instead.

Source: http://en.wikipedia.org/wiki/Transmission_Control_Protocol

Using TCP

Using TCP, applications on networked hosts can create connections to one another, over which they can exchange streams of data using stream sockets. TCP also distinguishes data for multiple connections by concurrent applications (e.g., Web server and e-mail server) running on the same host.

In the Internet protocol suite, TCP is the intermediate layer between the Internet Protocol (IP) below it, and an application above it. Applications often need reliable pipe-like connections to each other, whereas the Internet Protocol does not provide such streams, but rather only best effort delivery (i.e., unreliable packets). TCP does the task of the transport layer in the simplified OSI model of computer networks. The other main transport-level Internet protocols are UDP and SCTP.

Applications send streams of octets (8-bit bytes) to TCP for delivery through the network, and TCP divides the byte stream into appropriately sized segments (usually delineated by the maximum transmission unit (MTU) size of the data link layer of the network to which the computer is attached). TCP then passes the resulting packets to the Internet Protocol, for delivery through a network to the TCP module of the entity at the other end. TCP checks to make sure that no packets are lost by giving each packet a sequence number, which is also used to make sure that the data is delivered to the entity at the other end in the correct order. The TCP module at the far end sends back an acknowledgment for packets which have been successfully received; a timer at the sending TCP will cause a timeout if an acknowledgment is not received within a reasonable round-trip time (or RTT), and the (presumably) lost data will then be re-transmitted. The TCP checks that no bytes are corrupted by using a checksum; one is computed at the sender for each block of data before it is sent, and checked at the receiver.

Source: http://en.wikipedia.org/wiki/Transmission_Control_Protocol

Services Provided by TCP

TCP provides more services than UDP because it is connection oriented whereas UDP is not. TCP allows for point-to-point communication, adressing, multiplexing, demultiplexing, reliability, full-duplex communication, flow control and congestion control.

The reason the whole internet can actually even work is in part thanks to the design of TCP which can dynamically adapt to different properties such as bandwidth, delay and packet loss as well as recover from errors.

TCP splits user data into pieces no larger than 64K bytes and then sends each of these pieces as separate IP datagrams. When these IP datagrams are received at the destination, TCP reconstructs the original byte stream. In order to establish the connection between the sender and destination, sockets are used. Sockets are really just the combination of an IP address and a port number.

A connection is established between two computers using what is called a “three-way handshake”.

The originator (you, hopefully) sends an initial packet called a “SYN” to establish communication and “synchronize” sequence numbers in counting bytes of data which will be exchanged. The destination then sends a “SYN/ACK” which again “synchronizes” his byte count with the originator and acknowledges the initial packet. The originator then returns an “ACK” which acknowledges the packet the destination just sent him. The connection is now “OPEN” and ongoing communication between the originator and the destination are permitted until one of them issues a “FIN” packet, or a “RST” packet, or the connection times out. All the protocols of the Internet which need “connections” are built on the TCP protocol. The “three way handshake” establishes the communication. Much like you picking up your phone, getting a dial tone, dialing the number, hearing ringing, and then the other party saying “hello” or “mushi mushi.”

Source: http://www.pccitizen.com/threewayhandshake.htm

TCP also closes a connection gracefully. Upon closing, the last data segment is followed by a FIN which also has a sequence number associated with it. This way, if the FIN arrives before all segments are received, it will wait for the expected data before closing.

The biggest source of errors in message transmission come from segments damaged in transmission or segments which entirely fail to arrive. The sender obviously does not know if the message sent has been received at the destination or not so it is necessary in TCP for the receiver to acknowledge receipt. In UDP, since reliability is not a concern and since it is a connectionless protocol, this acknowledgment does not occur.

Of course, we need to switch our point of view as soon as the destination sends an acknowledgment because at this point the receiver is acting as a sender. It is therefore entirely possible that the acknowledgment message gets lost or damaged in transmission as well. Therefore, it is necessary to have timers on both the sender and receiver which trigger a re-send after a certain amount of time to make sure the application does not end up in a dead-lock state where both sides are waiting to receive something from the other.

What is the value of the timer? It is possible to have a fixed timer or to use an adaptive scheme. Depending on the network, different value will be more appropriate for different situations and even for a given network, the perfect value can change depending on the amount of traffic on the network. If the timer value is set to be too short, re-transmission will clog the network causing further delay and therefore leading to even more ACK’s being sent! This can therefore become a rather messy situation. Of course, if the timer is set too high, performance will suffer because the delay before re-transmission leads to the application sitting and waiting. Therefore, the ideal timer will have some functionality to be aware of network conditions and then use this information in order to dynamically increase or decrease the timer.

Another problem thatmust be dealt with arises from the fact that TCP re-transmits messages as stated above in order to guarantee transmission. Since messages and ACK’s may be re-transmitted, we suddenly end up in a situation where it is possible for the destination to receive duplicates. For example, imagine that the receiver sends an ACK in order to confirm receipt of a message but high network traffic causes this ACK to travel slowly. Meanwhile the sender is waiting for the ACK when suddenly it’s timer expires and it therefore decides to re-transmit the message. Right after sending the message the ACK might finally arrive, however the duplicate has already been sent! The sender will now not send the message a third time because the ACK was received but the receiver will need to deal with the duplicate message that will soon be arriving! In order to deal with duplicates, the receiver can use the sequence number to determine if the message has already been received. However, for this to work correctly we are assuming that the sequence number space is large enough that it does not restart within the life-span of a packet. In a nutshell, the sequence space is a fixed number. When a connection is established the first message always starts at the first sequence number and eventually, if the connections has been open long enough and many messages have been sent, eventually the last available sequence number is reached. At this point, the next message sent will start back at the first sequence number. Therefore, it is possible for two messages with the same sequence number to exist and not be duplicates!

Congestion is caused when too much traffic is flowing through a network that individual messages are delayed because messages are arriving more quickly than can be processed. When this occurs, routers will begin dropping packets, starting with those it feels are of a lower priority. Therefore, as congestion occurs, time-outs start to happen causing messages to be re-transmitted. This of course is done in order to make sure the message does in fact arrive, but for a system experiencing congestion, this reliability feature imply contributes to the congestion. TCP congestion control handles this by estimating the round trip delay by observing patterns of delay and then setting the timer so a value greater than the time estimated. The timer is set higher in order to account for round trip time variance.

RTO - Re-transmission timeout

As discussed above, a timer is set on both the sender and receiver upon transmitting a message. If an acknowledgment is not received before this timer expires then a time-out occurs which triggers the re-transmission of the message. Using a fixed timer is not a good idea because the main cause for such occurring is congestion. If congestion occurs on your network and you message times-out, if you re-transmit the same message and keep the timer at the same value, chances are the message will time-out yet again if network conditions have not improved. Therefore, if we assume congestion is the culprit, it is important to give the message some extra time upon re-transmission in order to see if this extra time is enough for it to reach the destination and be acknowledged. The act of increasing the timer each time a message is re-transmitted is referred to as re-transmission timeout backoff. The most common type of RTO backoff is binary exponential backoff which takes the current timer value and multiplies it by two each time a message is re-transmitted.

Another issue that is important to consider is with respect to shrinking the timer back down. Re-transmitted messages should never be used as a guage when measuring RTT (round trip time) because the acknowledgment received could actually be for the first message transmitted and not for the re-transmitted one! Therefore, the RTO backoff should continue to be used until an ACK arrives for a message that has not been re-transmitted. At this point, it is up to the designer to decide how to implement the system. The timer can be left constant for a given amount of time and then upon receiving a certain number of messages without needing to re-transmit, the timer value can be divided by two in order to shrink it back down, meaning that perhaps network conditions have improved.

Window Management

Slow-start is part of the congestion control used in TCP in order to avoid sending more data than the network is able to handle.

Slow-Start Algorithm

A slow-start algorithm consists of two distinct phases: the exponential growth phase, and the linear growth phase.

During the exponential growth phase, Slow-start works by increasing the TCP congestion window each time the acknowledgment is received. It increases the window size by number of segments acknowledged. This happens until either an acknowledgment is not received for some segment or a predetermined threshold value is reached. If a loss event occurs, TCP assumes this it is due to network congestion and takes steps to reduce the offered load on the network. Once a loss event has occurred or the threshold has been reached, TCP enters the linear growth (congestion avoidance) phase. At this point, the window is increased by 1 segment for each RTT. This happens until a loss event occurs.

Although the strategy is referred to as “slow-start”, its congestion window growth is quite aggressive.

The algorithm begins in the exponential growth phase initially with a congestion window size (cwnd) of 1 or 2 segments and increases it by 1 Segment Size (SS) for each ACK received. This behavior effectively doubles the window size each round trip of the network. This behavior continues until the cwnd reaches the size of the receivers advertised window or until a loss occurs.

When a loss occurs half of the current cwnd is saved as a Slow Start Threshold (SSThresh) and slow start begins again from its initial cwnd. Once the cwnd reaches the SSThresh TCP goes into congestion avoidance mode where each ACK increases the cwnd by SS*SS/cwnd. This results in a linear increase of the cwnd.

Source: http://en.wikipedia.org/wiki/Slow-start

TCP Data Transfer

When a TCP connection is established, a stream of bytes is what will actually be sent between communicating entities, not messages. Messages themselves can be sent by any combination of pieces which give a total of 2048 bytes. Therefore, is you wish to send 4 messages each of which are 512 bytes, TCP might not actually send your message right away if it is set to wait for a total of 2048 bytes before transmitting. If this is the case, it will not send your 512 byte messages until 4 of these such messages are ready to be sent. TCP could also instead be set to send 2 pieces each of size 1024 bytes, and therefore only 2 messages need be ready in order to be transmitted. The important thing to understand is that a message being ready to be sent does not mean that this message itself is sent, but rather pieces of bytes which are then re-combined in order to re-create the message. Also, its important to note that TCP may decide to wait with your message and collect more data before transmitting. Certain flags can be used in order to request no delay.

TCP Header

Source: http://www.visi.com/~mjb/Drawings/

TCP Header Fields

Source and destination port - 16 bit address corresponding to the port which is associated with the value defined in the socket used to establish the connection.

Sequence and acknowledgment numbers - These are both 32 bit numbers which are used to help ensure reliable delivery of messages. Every TCP packet send has a sequence number associated with it and the acknowledgment is used to communicate to the other entity which sequence number is expected next.

URG - this will be set to 1 if the urgent pointer is used. The pointer will indicate an offset from the current sequence number which informs the receiver at which point the urgent data ends.

ACK - set to 1 to indicate the acknowledgment is valid.

PSH - set to 1 to indicate pushed data. Pushed data is data that the sender force-delivered without waiting for the buffer to fill.

RST - set to 1 to indicate a reset. This can be used to reject a connection or to refuse an invalid segment. It can also be used if the host has become confused for whatever reason and therefore would like to re-establish the connection.

SYN - used in order to establish a connection. If SYN = 1 an ACK = 0 then a connection request is in progress. If SYN = 1 and ACK = 1 then a connection acceptance is in progress.

FIN - this is set to 1 in order to indicate the end of user data and to therefore close the connection. As discussed earlier, data may still be received after the FIN because the FIN also has a sequence number associated with it and it is possible that messages with an earlier sequence number arrive after the FIN which should actually be processed and which are.

TCP Error Checking

Error checking is accomplished by using the checksum field available in the TCP header. The receiver performs a calculation on the checksum field and the user data and if the result is not 0, this indicates that there is an error somewhere.

TCP Options

The options field available in the TCP header allows for extra features to be used or certain settings to be set. Below are some example:

- During connection, this field is used for connecting entities to negotiate an acceptable maximum segment size.

- Since network speeds have increased dramatically since TCP was first introduced, 16 bits used for sequence numbers is actually no longer enough and the problem of incorrect duplicate detection becomes a major concern. It is therefor possible to also use the options field to allow for an increase in the number of available sequence numbers from 2^16 to 2^32.

- The options field can also be used to include a time-stamp which can then be used in order to determine round trip time, information that can then be used for congestion control.

Additional Time Issues

Given all of the information presented above, there are some other issues to consider with respect to the timer. As mentioned a persistence timer is essential in order to avoid deadlock situations. This timer will expire and cause the last message to be re-transmitted if no acknowledgment is received in a timely fashion. When using congestion control, it is possible for the available window size to go down to 0, which causes the sender to stop sending messages temporarily until it is notified that there is space again in the window. Therefore, even in this situation it is still important to occasionally have a timer expire causing the sender to ask the receiver if it has space in its window. This is necessary because imagine if an acknowledgment sent increasing the window size is lost, the system would be stuck waiting forever!

Of course, the above assumes that the problem is due to congestion. It is possible that there is no connection but that the entity you are communicating with is no longer available or has gone offline. Is is therefore also important not to continue trying to send messages to this user forever, but to instead also maintain a keep-alive timer which will occasionally cause a message to be sent to the receiver asking, “are you still there?”. If no response is received, the connection should be terminated so resources are not wasted sending messages to an entity which is no longer available to receive these messages.

The transport layer is one of the 7 layers of the OSI model. It’s purpose is to provide robust end-to-end service to to the upper layers and is responsible for end-to-end delivery of the message. Therefore, the transport layer must consider addressing, reliability, flow control and multiplexing in order to accomplish it’s main goals.

Reliable delivery is not a compulsory service for the transport layer, however since this layer is expected to be responsible for delivering the messages from end-to-end, it only makes sense to implement reliable delivery at this layer. Reliable delivery is provided by using error control, sequence control, loss control and duplication control.

Sequence control is very important because messages not arriving in order can cause very important information to be lost or even overwritten. For example, when one process relies on another, the order in which messages arrive will influence the final result meaning that sequence errors will lead to errors in the application. This is similar to the complexities encountered when working with databases or other applications that are multi-threaded. Consider performing a mathematical calculation. If one process retrieves the stored value to be used in the calculation just before the second process updates that value, then even if that value is updated, the first process is unfortunately using the incorrect value for its calculation.

Of course, if sequence control is an important issue, obviously so it loss control! If messages are not even received, the complexity in dealing with such is far more complex than worrying about putting messages back in order which can be accomplished by the use of sequence numbers. If messages are being lost after transmission over a network, it is not necessary to somehow make sure the lost messages are re-sent in a timely fashion. All this must be accomplished in a way such that performance of the system and entire network is not compromised.

Duplication control is important to consider as well because as the speed of networks continue to increase, it becomes possible for different messages to be identified as duplicated and discarded. Similarly, if a packet can become corrupted or erroneous, it is possible then for the sequence number of a real message to be incorrect and cause a duplicate. Also it is entirely possible for a duplicate message to be sent by the sender itself, and therefore this duplicate should be detected to avoid errors.

Flow control is yet another important component of transport to consider. Imagine all these messages that are being delivered over a network, some coming from very high-speed users, others from slower users possibly still using a dial-up connection. Without flow control, a slower user could quickly become completely flooded with messages and suddenly be unable to do anything. Flow control therefore establishes window sizes to try and make sure the network or users do not run into this problem.

Multiplexing refers to the process where multiple messages are combined into a single signal. Demultiplexing is the reverse process of taking a single signal and splitting it into multiple messages. The transport layer performs a multiplexing (to data link layer)/demultiplexing(from data link layer) function with respect to the interface between itself and the layers below it.

With regard to the transport layer, a connection is not necessarily required since messages can be sent by UDP which is connectionless. Therefore, a connection is only required when a connection-oriented transport protocol is being used. If using a connection-oriented transport protocol, then it is important to consider the complexities involved with connection establishment and connection release. Establishing a connection is a rather straight-forward concept. A connection request is sent, and then the sender waits for an acknowledgment confirming the connection. However, problems can occur when duplicate or expired connection requests or acknowledgments show up!

UDP - User Datagram Protocol

UDP is a way of sending data over a network, however unlike TCP, ordering and reliability is not part of the protocol. Because this reduces a significant amount of overhead, UDP is actually faster and more efficient than TCP. However, for applications that require reliable or guaranteed delivery, UDP will not be acceptable. There is also no flow control or congestion control. UDP can have optional error detection, but does not have any method for recovery. Unlike TCP, UDP is compatible with packet broadcasting which is the sending of a message to everyone on a network

The transport layer is one of the 7 layers of the OSI model. It’s purpose is to provide robust end-to-end service to to the upper layers and is responsible for end-to-end delivery of the message. Therefore, the transport layer must consider addressing, reliability, flow control and multiplexing in order to accomplish it’s main goals.

Reliable delivery is not a compulsory service for the transport layer, however since this layer is expected to be responsible for delivering the messages from end-to-end, it only makes sense to implement reliable delivery at this layer. Reliable delivery is provided by using error control, sequence control, loss control and duplication control.

Sequence control is very important because messages not arriving in order can cause very important information to be lost or even overwritten. For example, when one process relies on another, the order in which messages arrive will influence the final result meaning that sequence errors will lead to errors in the application. This is similar to the complexities encountered when working with databases or other applications that are multi-threaded. Consider performing a mathematical calculation. If one process retrieves the stored value to be used in the calculation just before the second process updates that value, then even if that value is updated, the first process is unfortunately using the incorrect value for its calculation.

Of course, if sequence control is an important issue, obviously so it loss control! If messages are not even received, the complexity in dealing with such is far more complex than worrying about putting messages back in order which can be accomplished by the use of sequence numbers. If messages are being lost after transmission over a network, it is not necessary to somehow make sure the lost messages are re-sent in a timely fashion. All this must be accomplished in a way such that performance of the system and entire network is not compromised.

Duplication control is important to consider as well because as the speed of networks continue to increase, it becomes possible for different messages to be identified as duplicated and discarded. Similarly, if a packet can become corrupted or erroneous, it is possible then for the sequence number of a real message to be incorrect and cause a duplicate. Also it is entirely possible for a duplicate message to be sent by the sender itself, and therefore this duplicate should be detected to avoid errors.

Flow control is yet another important component of transport to consider. Imagine all these messages that are being delivered over a network, some coming from very high-speed users, others from slower users possibly still using a dial-up connection. Without flow control, a slower user could quickly become completely flooded with messages and suddenly be unable to do anything. Flow control therefore establishes window sizes to try and make sure the network or users do not run into this problem.

Multiplexing refers to the process where multiple messages are combined into a single signal. Demultiplexing is the reverse process of taking a single signal and splitting it into multiple messages. The transport layer performs a multiplexing (to data link layer)/demultiplexing(from data link layer) function with respect to the interface between itself and the layers below it.

With regard to the transport layer, a connection is not necessarily required since messages can be sent by UDP which is connectionless. Therefore, a connection is only required when a connection-oriented transport protocol is being used. If using a connection-oriented transport protocol, then it is important to consider the complexities involved with connection establishment and connection release. Establishing a connection is a rather straight-forward concept. A connection request is sent, and then the sender waits for an acknowledgment confirming the connection. However, problems can occur when duplicate or expired connection requests or acknowledgments show up!

UDP - User Datagram Protocol

UDP is a way of sending data over a network, however unlike TCP, ordering and reliability is not part of the protocol. Because this reduces a significant amount of overhead, UDP is actually faster and more efficient than TCP. However, for applications that require reliable or guaranteed delivery, UDP will not be acceptable. There is also no flow control or congestion control. UDP can have optional error detection, but does not have any method for recovery. Unlike TCP, UDP is compatible with packet broadcasting which is the sending of a message to everyone on a network

Associative Law:

Distributive Law:

Tautology Law:

Absorption Law:

Demorgan’s Law:

Double Complementation:

Implication:

Complementation:

Disjunction:

Conjunction:

—

[1] - Images from Thomas Jefferson High School for Sciene and Technology

Associative Law:

Distributive Law:

Tautology Law:

Absorption Law:

Demorgan’s Law:

Double Complementation:

Implication:

Complementation:

Disjunction:

Conjunction:

—

[1] - Images from Thomas Jefferson High School for Sciene and Technology

Examples from [1]:

1) Construct a DFA to accept a string containing a zero followed by a one.

2) Construct a DFA to accept a string containing two consecutive zero’s followed by two consecutive ones.

3) Construct a DFA to accept a string containing even number of zeros and any number of ones.

4) Construct a DFA to accept all stings which do not contain three consecutive zeros.

5) Construct a DFA to accept all strings containing even number of zeros and even number of ones.

6) Construct a DFA to accept all strings which satisfy #(x)mod5=2.

7) Construct a DFA to accept all strings (0+1)* with an equal number of zeros and ones such that each prefix has at most one more zero than ones and at most one more one than zeros.

—

[1] - Model Engineering College -

Examples from [1]:

1) Construct a DFA to accept a string containing a zero followed by a one.

2) Construct a DFA to accept a string containing two consecutive zero’s followed by two consecutive ones.

3) Construct a DFA to accept a string containing even number of zeros and any number of ones.

4) Construct a DFA to accept all stings which do not contain three consecutive zeros.

5) Construct a DFA to accept all strings containing even number of zeros and even number of ones.

6) Construct a DFA to accept all strings which satisfy #(x)mod5=2.

7) Construct a DFA to accept all strings (0+1)* with an equal number of zeros and ones such that each prefix has at most one more zero than ones and at most one more one than zeros.

—

[1] - Model Engineering College -

• Read more about CISC (Complex Instruction Set Computer)
• Read more about RISC ( Reduced Instruction Set Computer)

Load/Store/Load Effective Address [2]

Ex: X = $1234, Y=$1000, SP=$0A00

Stack Instructions [2]
SP is decremented before information is transferred

Increment/Decrement [2]

Addition and Subtraction [2]

—

[1] Fredrick M. Cady, Software and Hardware Engineering: Assembly and C Programming for the Freescale HCS12 Microcontroller
[2] Prof. Gilbert Arbez, University of Ottawa CSI3531 Course Notes, Module 4

• Read more about CISC (Complex Instruction Set Computer)
• Read more about RISC ( Reduced Instruction Set Computer)

Load/Store/Load Effective Address [2]

Ex: X = $1234, Y=$1000, SP=$0A00

Stack Instructions [2]
SP is decremented before information is transferred

Increment/Decrement [2]

Addition and Subtraction [2]

—

[1] Fredrick M. Cady, Software and Hardware Engineering: Assembly and C Programming for the Freescale HCS12 Microcontroller
[2] Prof. Gilbert Arbez, University of Ottawa CSI3531 Course Notes, Module 4

A program created from assemblhy can be more efficient and faster than a program created with a compiler. One example of why this occurs is because a compiler will store intermediate values used in a calculation in memory whereas a program written in assembly can store the intermediate values in a register which is much faster. However, while there may be performance benefits to programming so close to the machine level, there is a great deal of added complexity which a high-level programming language can remove.

Table 5.1 Source Code Fields [1]

• A label must start with an alphabetic character
• The label must start in the first column of the source code line unless it ends with a colon.
• Uppercase and lowercase characters are distinct by default but case sensitivity may be turned off.
• A label may end with a colon (:)
• A label may appear on a line by itself
• The label is optional but when used it can provide a symbolic memory reference such as a branch instruction address, or a symbol for a constant.

• The opcode field contains either a mnemonic for the operation, an assembler directive or pseudo-operation, or a macro name. For the opcode field, the assembler will convert all uppercase letters to lowercase so this field is not case sensitive.

• The interpretation of the operand field depends on the opcode.
• The operand must follow the opcode.
• Operands can be the symbols, constants, or expressions that are evaluated by the assembler.
• The operand field also specifies the addressing mode for the instruction.

Using Macros

A macro can be used to give a symbolic name to a group of instructions that are used often. In the source code the macro should be given a name using the label field and then two commands (MACRO & ENDM) are used to indicate the start and finish of the macro. The assembler will then replace every occurrence of the macro with the set of instructions.

Macro vs Sub-Routine

A macro and a sub-routine are similar except for the following differences:

• With a sub-routine the code is present only once. With a macro, the code is inserted in the place of the macro whenever it is used. Therefore, if macros are used instead of sub-routines, the code will end up being longer.
• With a sub-routine a jump must occur in order to find and execute the sub-routine code. With a macro, this is not required because the code has already been inserted directly. Therefore, a sub-routine will be slightly slower than a macro.

Using either a sub-routine or a macro makes changing the code much easier because changes can be done in one place rather than in each specific location where the code would be used. They also make the code easier to understand.

Assembler Instructions

ORG - Set the program counter to the origin of the program

EQU - Associate the value of an expression with a symbol

SET - Can be used instead of equal. With set, the value can be redefined

DC - Define a constant value

DCB - Define a constant block

DS - Define storage

Example 5-9 ORG - Set Program Counter to Origin for Absolute Assembly [1]

Software Development Process

When programming in any language, following a good development process is necessary in order to deliver a successful product. It is important to resist the urge to jump right into the code immediately, especially when programming in assembly which is extremely complex.

The first step should always be to clearly identify the problem and define a solution to solve that problem. Create and understand the solution in diagrams or pseudo-code before beginning to code in assembly. Translating these diagrams into code will be much easier than trying envision the solution entirely in your mind.

Debugging and tracing through your assembly program will also be a very good way at finding and correcting bugs.

Typical Bugs Include:

• Incorrect transfer to sub-routine
• Forgetting to initialize the stack pointer
• Not enough memory in the stack
• Sub-routines corrupting registers
• Forgetting to initialize index registers
• Modifying the condition code registers before branching
• Using the wrong branching instruction
• Using the wrong addressing mode

D-Bug12
The D-Bug12 is the debugging tool stored in the EEPROM of our microcontroller that will be used for debugging as well as for downloading programs onto the card and controlling the assembler.

D-Bug12 Commands

ASM - Assemble/Dissasemble

BF - Block Fill Memory

BR - Set Breakpoint

CALL - Call and execute subroutine

G - Go, run program

GT - Go till an address

HELP - Prints summary of available commands

LOAD - Set in state ready to accept program download from MiniIDE

MD - Display Contents of Memory

MM - Modify Memory

MOVE - Copy block of memory

NOBR - Remove breakpoints

RD - Display register contents

T - Trace through program

UPLOAD - Upload memory to PC

USEHDB - Use EVB/Target hardware breakpoints

VERIF - Compare memory to download file

—

[1] Fredrick M. Cady, Software and Hardware Engineering: Assembly and C Programming for the Freescale HCS12 Microcontroller
[2] Prof. Gilbert Arbez, University of Ottawa CSI3531 Course Notes, Module 3

A program created from assemblhy can be more efficient and faster than a program created with a compiler. One example of why this occurs is because a compiler will store intermediate values used in a calculation in memory whereas a program written in assembly can store the intermediate values in a register which is much faster. However, while there may be performance benefits to programming so close to the machine level, there is a great deal of added complexity which a high-level programming language can remove.

Table 5.1 Source Code Fields [1]

• A label must start with an alphabetic character
• The label must start in the first column of the source code line unless it ends with a colon.
• Uppercase and lowercase characters are distinct by default but case sensitivity may be turned off.
• A label may end with a colon (:)
• A label may appear on a line by itself
• The label is optional but when used it can provide a symbolic memory reference such as a branch instruction address, or a symbol for a constant.

• The opcode field contains either a mnemonic for the operation, an assembler directive or pseudo-operation, or a macro name. For the opcode field, the assembler will convert all uppercase letters to lowercase so this field is not case sensitive.

• The interpretation of the operand field depends on the opcode.
• The operand must follow the opcode.
• Operands can be the symbols, constants, or expressions that are evaluated by the assembler.
• The operand field also specifies the addressing mode for the instruction.

Using Macros

A macro can be used to give a symbolic name to a group of instructions that are used often. In the source code the macro should be given a name using the label field and then two commands (MACRO & ENDM) are used to indicate the start and finish of the macro. The assembler will then replace every occurrence of the macro with the set of instructions.

Macro vs Sub-Routine

A macro and a sub-routine are similar except for the following differences:

• With a sub-routine the code is present only once. With a macro, the code is inserted in the place of the macro whenever it is used. Therefore, if macros are used instead of sub-routines, the code will end up being longer.
• With a sub-routine a jump must occur in order to find and execute the sub-routine code. With a macro, this is not required because the code has already been inserted directly. Therefore, a sub-routine will be slightly slower than a macro.

Using either a sub-routine or a macro makes changing the code much easier because changes can be done in one place rather than in each specific location where the code would be used. They also make the code easier to understand.

Assembler Instructions

ORG - Set the program counter to the origin of the program

EQU - Associate the value of an expression with a symbol

SET - Can be used instead of equal. With set, the value can be redefined

DC - Define a constant value

DCB - Define a constant block

DS - Define storage

Example 5-9 ORG - Set Program Counter to Origin for Absolute Assembly [1]

Software Development Process

When programming in any language, following a good development process is necessary in order to deliver a successful product. It is important to resist the urge to jump right into the code immediately, especially when programming in assembly which is extremely complex.

The first step should always be to clearly identify the problem and define a solution to solve that problem. Create and understand the solution in diagrams or pseudo-code before beginning to code in assembly. Translating these diagrams into code will be much easier than trying envision the solution entirely in your mind.

Debugging and tracing through your assembly program will also be a very good way at finding and correcting bugs.

Typical Bugs Include:

• Incorrect transfer to sub-routine
• Forgetting to initialize the stack pointer
• Not enough memory in the stack
• Sub-routines corrupting registers
• Forgetting to initialize index registers
• Modifying the condition code registers before branching
• Using the wrong branching instruction
• Using the wrong addressing mode

D-Bug12
The D-Bug12 is the debugging tool stored in the EEPROM of our microcontroller that will be used for debugging as well as for downloading programs onto the card and controlling the assembler.

D-Bug12 Commands

ASM - Assemble/Dissasemble

BF - Block Fill Memory

BR - Set Breakpoint

CALL - Call and execute subroutine

G - Go, run program

GT - Go till an address

HELP - Prints summary of available commands

LOAD - Set in state ready to accept program download from MiniIDE

MD - Display Contents of Memory

MM - Modify Memory

MOVE - Copy block of memory

NOBR - Remove breakpoints

RD - Display register contents

T - Trace through program

UPLOAD - Upload memory to PC

USEHDB - Use EVB/Target hardware breakpoints

VERIF - Compare memory to download file

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[1] Fredrick M. Cady, Software and Hardware Engineering: Assembly and C Programming for the Freescale HCS12 Microcontroller
[2] Prof. Gilbert Arbez, University of Ottawa CSI3531 Course Notes, Module 3

BritneySpears.com is currently asking people to send their thoughts and inspiration to Britney Spears. I sent a letter, but unfortunately they have not yet posted it:

“Dear Britney Spears,

I know you may have lost contact with reality for the time being and that you are probably unaware that your vivid hallucinations and delusions are unrealistic. Delusions typically occur in the context of neurological or mental illness and are associated with many psychotic disorders, including schizophrenia. Don’t let your paranoia get you down or lead you to irrational or excessive behaviour. I think it’s great that your website is having all the 12 year olds, for whom you are a role model, send you letters of support. If you were poor, homeless and living in a third world country without your own personal fan-site, you’d have to face your psychosis alone. We’re all here for you. Not because we know you or really care, but because media and pop culture have dictated your importance so that we don’t bother politicians about wars in Iraq or climate change.

Hope you’re well soon, or at least before your children have hair to shave!”

I encourage everyone to send in their own letters of support! I also highly encourage someone to Photoshop a picture of her with a plunger stuck to her bald head. Some might say I’ve become obsessed with plungers as of late, but obviously my issues are only secondary in comparison to the idea of head shaving for the purpose of time travel.

BritneySpears.com is currently asking people to send their thoughts and inspiration to Britney Spears. I sent a letter, but unfortunately they have not yet posted it:

“Dear Britney Spears,

I know you may have lost contact with reality for the time being and that you are probably unaware that your vivid hallucinations and delusions are unrealistic. Delusions typically occur in the context of neurological or mental illness and are associated with many psychotic disorders, including schizophrenia. Don’t let your paranoia get you down or lead you to irrational or excessive behaviour. I think it’s great that your website is having all the 12 year olds, for whom you are a role model, send you letters of support. If you were poor, homeless and living in a third world country without your own personal fan-site, you’d have to face your psychosis alone. We’re all here for you. Not because we know you or really care, but because media and pop culture have dictated your importance so that we don’t bother politicians about wars in Iraq or climate change.

Hope you’re well soon, or at least before your children have hair to shave!”

I encourage everyone to send in their own letters of support! I also highly encourage someone to Photoshop a picture of her with a plunger stuck to her bald head. Some might say I’ve become obsessed with plungers as of late, but obviously my issues are only secondary in comparison to the idea of head shaving for the purpose of time travel.

We all know Poland is a major destination for tourists because of the cheap beer. We also know that this cheap beer possibly provides the Scots with the necessary motivation to run around Poland exposing themselves. Unfortunately, rather than turning towards violence or driving under the influence, Scots are perfectly content with hiding behind tree’s ready to flash unsuspecting victims. This sort of behaviour is not generally well received. In fact, many polish citizens have reported feeling frightened upon discovering what the drunk Scots have under their kilts.

Now let me explain how this will lead to an increase in the price of alcohol. First of all, drunk Scots can only stagger so far when drunk before collapsing unconscious in a ditch. This means that the under-kilt-sightings will have a highest density within the staggering radius surrounding the bars in Poland. We will refer to this as the “Flashing Zone of Terror”. Frightened citizens will avoid the Flashing Zone of Terror at all cost meaning many will avoid Poland’s bars. If you’ve studied Supply vs Demand in economics then you know that as the demand goes down so does the price. However, in this case, decreasing the price will only attract more Scottish flashers. Therefore, tourists will inevitably be content to pay significantly more for their beer if the end result is less exposed testes.

Don’t let the drunk Scottish kilt lifters raise the price of beer in Poland! It’s time to enter the Flashing Zone of Terror and fight back. Take out the plungers, you know what to do when you see that kilt-lift!

We all know Poland is a major destination for tourists because of the cheap beer. We also know that this cheap beer possibly provides the Scots with the necessary motivation to run around Poland exposing themselves. Unfortunately, rather than turning towards violence or driving under the influence, Scots are perfectly content with hiding behind tree’s ready to flash unsuspecting victims. This sort of behaviour is not generally well received. In fact, many polish citizens have reported feeling frightened upon discovering what the drunk Scots have under their kilts.

Now let me explain how this will lead to an increase in the price of alcohol. First of all, drunk Scots can only stagger so far when drunk before collapsing unconscious in a ditch. This means that the under-kilt-sightings will have a highest density within the staggering radius surrounding the bars in Poland. We will refer to this as the “Flashing Zone of Terror”. Frightened citizens will avoid the Flashing Zone of Terror at all cost meaning many will avoid Poland’s bars. If you’ve studied Supply vs Demand in economics then you know that as the demand goes down so does the price. However, in this case, decreasing the price will only attract more Scottish flashers. Therefore, tourists will inevitably be content to pay significantly more for their beer if the end result is less exposed testes.

Don’t let the drunk Scottish kilt lifters raise the price of beer in Poland! It’s time to enter the Flashing Zone of Terror and fight back. Take out the plungers, you know what to do when you see that kilt-lift!

While Colbert bids farewell to Captain America, one has to wonder, did he do it? One may argue that he lacks the qualities of a super hero villain, but what if Stephen Colbert is really the alter ego of Crossbones or Dr.Faustus?! Let’s not forget Colbert’s performance at the White House Correspondents’ Association dinner… According to Michael Scherer, “Stephen Colbert is a dangerous man — a bomb thrower, an assassin, a terrorist with boring hair and rimless glasses. It’s a wonder the Secret Service let him so close to the president of the United States.”

Colbert has appeared in Maxim Online and People Magazine as one of the sexiest men alive. Most TV news anchors are not naturally attractive or they would have a better job, so this strengthens the alter ego argument as Colbert is obviously wearing a mask.

If you think the evidence ends there you are wrong! Once Captain America realizes that his fight against the Registration Act is putting the lives of civilians in danger, he orders the anti-Registration forces to stand down. Colbert, who had a vested interest in the liberty of the super-powered beings via his ice cream business (i.e. Stephen Colbert’s AmeriCone Dream - …the sweet taste of liberty…), could not allow the fight against registration to be lost, and thus needed to murder Captain America in order to allow a new leader, possibly Punisher, to continue the battle!

You see, the Comics Code Authority (CCA) was created to regulate the content of comic books and prevents super-powered beings from consuming alcohol. Colbert knew that when the sale of alcohol was made illegal in the United States during the prohibition between 1920-1933 the demand for ice cream soared up by 71%. If the registration act were to come into effect, the identities of all super-powered beings would be known and therefore they would gain the right to consume alcohol since by law they would now be entitled even as a super-beings, to their rights as regular civilians. The impact would have dramatic results on Colbert’s ice cream business.

Do not let the fact that Captain America is a comic book character stand in the way of justice. Stephen Colbert must pay for the crimes he has committed! Get out your plungers and stand up for Steve Rogers. Don’t let fiction and reality become two separate entities!

While Colbert bids farewell to Captain America, one has to wonder, did he do it? One may argue that he lacks the qualities of a super hero villain, but what if Stephen Colbert is really the alter ego of Crossbones or Dr.Faustus?! Let’s not forget Colbert’s performance at the White House Correspondents’ Association dinner… According to Michael Scherer, “Stephen Colbert is a dangerous man — a bomb thrower, an assassin, a terrorist with boring hair and rimless glasses. It’s a wonder the Secret Service let him so close to the president of the United States.”

Colbert has appeared in Maxim Online and People Magazine as one of the sexiest men alive. Most TV news anchors are not naturally attractive or they would have a better job, so this strengthens the alter ego argument as Colbert is obviously wearing a mask.

If you think the evidence ends there you are wrong! Once Captain America realizes that his fight against the Registration Act is putting the lives of civilians in danger, he orders the anti-Registration forces to stand down. Colbert, who had a vested interest in the liberty of the super-powered beings via his ice cream business (i.e. Stephen Colbert’s AmeriCone Dream - …the sweet taste of liberty…), could not allow the fight against registration to be lost, and thus needed to murder Captain America in order to allow a new leader, possibly Punisher, to continue the battle!

You see, the Comics Code Authority (CCA) was created to regulate the content of comic books and prevents super-powered beings from consuming alcohol. Colbert knew that when the sale of alcohol was made illegal in the United States during the prohibition between 1920-1933 the demand for ice cream soared up by 71%. If the registration act were to come into effect, the identities of all super-powered beings would be known and therefore they would gain the right to consume alcohol since by law they would now be entitled even as a super-beings, to their rights as regular civilians. The impact would have dramatic results on Colbert’s ice cream business.

Do not let the fact that Captain America is a comic book character stand in the way of justice. Stephen Colbert must pay for the crimes he has committed! Get out your plungers and stand up for Steve Rogers. Don’t let fiction and reality become two separate entities!

If we don’t start a petition now to bring back Antonella Barba, her moment of fame will be over until the release of the next Girl’s Gone Wild DVD. If we wait that long to stand up for what’s right, the world as we know it could cease to exist. Already research has shown that more and more people are searching Google for the word “rhombus“. Do you know what a “rhombus” is? It’s not the shape that should be most searched for on the Internet if you know what I mean…

Do you want your children to grow up in a world where everyone cares more about inequality and geometry than XXX porn? Do your part to save our culture, bring back Antonella Barba!

If we don’t start a petition now to bring back Antonella Barba, her moment of fame will be over until the release of the next Girl’s Gone Wild DVD. If we wait that long to stand up for what’s right, the world as we know it could cease to exist. Already research has shown that more and more people are searching Google for the word “rhombus“. Do you know what a “rhombus” is? It’s not the shape that should be most searched for on the Internet if you know what I mean…

Do you want your children to grow up in a world where everyone cares more about inequality and geometry than XXX porn? Do your part to save our culture, bring back Antonella Barba!