computer technology

Network Monitoring for Serious eCommerce

2011-09-26T01:40:00.001-07:00

In the real world, businesses come in every size, from self-employed entrepreneurs like me to mega malls like Wal-Mart.

On the Internet, companies come in every size, too, from a stand-alone ebook sales page with webmaster and owner all in one, to 300 pound gorilla like Amazon, with over a million pages, who requires the entire population of a small country to serve as webmaster.

If your site is a single page, it is its own network. But if your site is any bigger, and you have plans to grow, it is a network or is fast becoming one. You need network monitoring.

Most ecommerce webmasters are at least somewhat familiar with website monitoring. Many use a website monitoring service or software to keep track of "uptime" and "downtime".

At your local shopping mall, serious business requires more than just knowing when the front doors are open and when they are closed. Serious ecommerce needs to know more than just when the site is accessible. That is what network monitoring is all about.

hances are, your e-business owns one of the following, or uses one of the following remotely:

DNS servers: These are used to translate your site name, like www.URL.com, to the numbers called "IP addresses" that computers understand. If DNS servers are not working properly, end-users will not be able to find your site and will get an error. Usually only an external or remote monitoring service will detect such a problem.

An FTP server: File Transfer Protocol servers are used to help you
exchange files with remote users. If you use FTP, a monitoring
service can make sure it is always up and running.

POP3 and SMTP servers: These are used for exchanging emails. If you are using email, chances are you are using SMTP and POP3. If your SMTP server is down, everyone who sends you email will receive an error, stating that your mail server is down and cannot accept incoming email. To say that the impression this leaves your customers is bad would be an understatement. If your POP3 server is down, you will be unable to retrieve email from your mailbox. Once again, only external monitoring will prevent such a problem.
<
Firewalls: Many businesses use firewalls to protect their internal network from un-authorized traffic, such as spyware, viruses and sabotage by competitors. Furthermore, a firewall is your first line of defense. If your firewall goes down, your whole network may actually become inaccessible from outside. In other words, if you host your own web site and mail servers, those will become
inaccessible to the outside world if your firewall goes down. Once again, remote network monitoring is required to detect that a problem exists and quickly get it repaired.

Internet connections: Users come to your network from multiple backbones, depending on the company they use to connect to the Internet and their location. It is important to insure that your connection performs well for each user. A remote monitoring service can ping your networks from multiple locations around the world, thus testing most major routes to your web server or network. Before hiring a network monitoring service, check to see that they have both your customer geography and the Internet backbone layout covered.

Very few websites of any size and functionality are anything less than a complete network, and many networks rely on servers in different parts of the world.

A good network monitoring service can ensure, as a base, that all servers are properly functioning, that data can be sent to and received from each server, and that each function sharing the server responds as required. An advanced network monitoring service can even remotely monitor the temperature of your servers.

What you need to monitor depends on how extensive your network is. A network monitoring expert can help you determine what needs monitoring. If you own the servers, or are remotely hosted on dedicated servers, you most likely need everything monitored. If your site is hosted on shared servers, you might need fewer functions monitored.

Digital Cameras - Quality Vs. Size

2011-09-22T07:27:00.001-07:00

When looking to purchase a new digital camera there is always the debate between size and quality within the range of your budget. No matter what the budget, the choice will have to be made between a smaller size, more portable camera and a higher resolution camera with more features. Making the choice between the two is simply a matter off considering what the camera's purpose.

Digital camera users who plan to use a camera for simple point-and-shoot purposes will want to focus their budget on a small, portable camera. These individuals are most likely using their camera to document travels, family events, and personal experiences for their own memory. The photos don't need to be or a super high resolution because they will not be blown up to poster size, but will remain 4 x 6 or 5 x 7 in a frame on the mantel. It is important to consider that when size is traded for quality, while the photos will be higher quality, users may be less inclined to take photos as the size of the camera becomes a hindrance to taking it along for the fun.

Photographers who are more interested in the end product will want to sacrifice size for a higher resolution camera or one with more features and/or accessories. The bulkier high-resolution cameras or digital SLRs will be the better choice for users who are taking artistic or professional photographs. Even the amateur artist, will want to invest in quality over size to produce the kind of photos that can be enlarged to show detail. Cameras used for professional shots, whether to be displayed in a portfolio, brochure or website, will also need to be of higher quality, and it will be worth hefting the extra weight to get the higher-end photos.

Knowing the type of photographer you are, will help you make the right choice in cameras. When you have an idea of what characteristics are most important to you, take the time to shop, read the reviews, and compare the various cameras in your price range.

Care for Your Laptop in a Few Easy Steps

2011-09-17T18:37:00.000-07:00

Your laptop can be your constant companion throughout the day. You may use this portable computing device for work, fun or school. With so many uses, it is crucial that you keep your laptop at its best to experience its highest performance. By following a few basic steps, your computing device will last longer and you won’t have to deal with a handful of maintenance issues.
Don’t Be Afraid to Spend Money
To keep a laptop healthy, it may require a little extra from your pocketbook. First, be willing to spend money on antivirus software. You never know when a file you download or an internet site you visit will contain a bug that will crash your computer. Taking the time to find a strong security software application will help you avoid a slow and sluggish laptop and will keep your computer healthy.
The system hardware is not the only thing to protect on your laptop. Purchasing a protective case for your laptop not only increases its portability, but it also keeps your laptop’s exterior free from scratches and protects it from extreme temperatures and liquids or other materials that may be spilled on it. There is an assortment of these cases available, so you can find one that best fits your style.
The Screen is Everything
You can easily damage your display monitor without any thought. By simply shutting the computer with a pencil or other item sitting on the keyboard, or even closing the laptop too hard, you can cause extensive damage to your display. Make sure your keyboard is clear of objects when shutting your laptop, and remember to keep your keyboard keys clean. You don’t want dirt particles transferring from the keyboard to your display screen.
Avoid Jamming and Cramming
Don’t try to force any drives into their slots. If you do so, you may jam the device and cause significant damage to the computer. Insert drives carefully and avoid putting anything in the wrong drive, upside down or at an angle. Take the time to insert drives correctly. It will save you a lot of hassle and many headaches if you do.
Avoid the Heat and the Cold
Be cautious about the laptop’s temperature. Extreme temperatures can cause serious damage to your battery. For example, don’t ever leave your laptop in your car. The summer heat and the winter cold are both serious problems that can quickly kill your battery. A good rule of thumb is to store your laptop in temperatures ranging between 40–95 degrees Fahrenheit.
Don’t Forget the Basics
Your laptop is an important piece of equipment, and it is crucial for you to be mindful of all your actions around this computing device. Avoid eating or drinking when you use the computer. It is easy to spill or drop food on it, and accidents do happen. Don’t place anything heavy on top of the laptop, and make sure you don’t force your laptop into a bag filled with heavy books, which can crush the device. Remember also to avoid using your computer near pools or other large bodies of water. One slip or other mishap and you can say goodbye to your laptop computer and all the files on your hard drive, unless you have backups.

Cabling your home for computer network - still a requirement?

2011-09-14T00:41:00.000-07:00

With proliferation of wireless networking and communication equipment it is oh-so-tempting to cut the cord and save a significant sum of money in the process. But is everything that a regular computer networking user needs can be done using just wireless network? Let's take a look at some pros and contras:1. One important advantage of having a cabled network is the available bandwidth or simply speed. At the present point in time the speed of connection via a simple and inexpensive CAT5E cable can be 1000Mbit/sec, whereas the best that IEEE802.11g (one of the many flavors of Wi-Fi) can offer is only 54Mbit/sec. It may not seem so significant if you think you are only browsing Internet, and the DSL speed available to you is 1.5Mbit/sec. However, if you need to print via your network connection on a remote printer, you should realize that the print jobs, depending on the amount of graphic data in them, can easily reach dozens and even hundreds megabytes. Since 1Byte=8bit one 100MByte print job will take 15 seconds (and in reality this time can be much longer) to transmit via a Wi-Fi wireless connection, and this time shrinks to mere 1 sec or less on wired 1000MBit/s Ethernet connection. Same principal applies to transferring files, backing up files on other computers in the network etc.2. It is not possible today and with all probability will not be possible in the future to transmit power needed for your networking device via the wireless link. Unless, of course, you would be willing to be subjected to very high levels of microwave radiation. Thus a device that was marketed to you as "un-tethered" will in fact be very much tethered via the power cord or will have to be re-charged every so often. The power requirements are increasingly important for devices that are expected to be always online, such as phone sets. Therefore it is best to have it connected via a cable that can deliver both power and the communication signal at the same time.3. Wireless communications are very much proprietary and require whole gamut of conversion equipment to transmit multi-media signals. The same CAT5E cable can without any modification support phone, computer network, balanced line level audio signal, baseband video signal as well as host of other, more specialized, control applications' signals. With inexpensive adapters called "baluns" the same cable can carry significant number of channels of broadband television or carry a baseband video, such as security camera output, through great distances. All of those applications, except the computer network of course, will require specialized expensive conversion equipment if they needed to be transmitted via a Wi-Fi link.

4. The cost benefit of not running wires around the house is not as simple as issue as it seems. Having installed a wireless network at home you have only eliminated the need to wire for a single application – computer network. A modern home, however, requires all kinds of wiring to run even without regard to computers. The power and phones are obvious examples, as well as thermostats and security systems. Pre-wired speakers are common and most homes today have intercom systems as a desirable option, and those also require extensive wiring. It is very likely that the same contractor running the intercom or security cables is qualified to run computer cables – CAT5E or better. If you are building a home, you should definitely check if computer cabling option is available in your new home, and our advice is to go ahead and purchase it before the walls close. It is going to be a pretty involved and expensive procedure to install the cables later. As an added cost benefit of a wired computer network you will find that all modern computers ship with wired Ethernet network interface card included, and the latest models ship with 1000MBit/sec cards that are essentially free for the computer's owner.

There are multiple sources of information available on proper planning and design of a residential cabling for voice, data, audio, video and other applications. One of the best sources is the TIA/EIA-570B standard, most resent release of which has been published in 2004. The standard outlines recommended types of the cables, principals of cable distribution in a single- and multi-dwelling units as well as recommended amount of cables to be installed based on the size of the house.In conclusion, cutting the wire seems like a step forward, some sort of liberation of computer from the bonds of the infrastructure. I would caution the reader, however, to take a more balanced and informed approach before joining the wireless revolution. There are still (and will remain in foreseen future) sound reasons to include properly designed cabling system into the list of your dream home options.

iPods- which rock the world

2011-09-11T23:56:00.001-07:00

Wondering why people are becoming crazy about this miniature audio device? iPods offer excellent quality of digital music. The success of iPod is due to its features like:

•iPod is able to deliver extremely rich quality of digital music.
•It comes in attractive small sizes and thus tends to be very handy and compact.
•They come with in-built media library software, called as the iTunes media library software. This feature enables the user to manage the music files efficiently.
•The most attractive feature which made iPod the best seller is the attribute which allows the device to be connected to the user's computer.
•Thus by enabling connection with the user's computer, the iPod prove to serve as efficient storage devices.
•iPods sport a display, which makes the gadget more user friendly.
•Improvised iPods also had PDA's( Personal Digital Assitants).
•Apple, the creators of iPod kept on improvising it, and thus many models of iPod have rocked the market.

The models of iPod categorized according to the chronological order.

First Generation iPods:

Initially the iPods were released with 5GB hard drive, but then later Apple increased their hard drive capacity to 10GB. These iPods have a scroll wheel with a select button in the middle. This device was a huge hit in the commercial market, but now they rarely exist due to the release of new models.

Second generation iPods:

These devices had a thicker body and they supported 20 GB hard drive. They were the first gadgets, which were compatible with the windows. They also sported cases and wired remotes.

Third generation iPods:

These iPods were thinner than the original versions, the 30 pin dock connector was introduced with this series. They also had touch sensitive buttons this attracted the masses to a great extent. And it did not have buttons surrounding the wheels and hanging parts.<

Fourth generation iPods:

The only difference, the fourth generation iPods had over the others is the introduction of click wheels. They also sported the same monochrome screen. But it enabled the battery to be charged through the USB connection.

Color iPods:

As the name suggests these devices had a color screen and the ability to store and display JPEG, BMP, GIF, TIFF, and PNG images. They supported 65,536 colors. They possessed the photo library and released accessories like iPod camera connector.

Fifth generation iPods:

They were developed to reduce minor audio effects so that the head phone does not deliver hard drive noise. They came in a wide variety of sizes, colors and hard drive capacities. They also supported features like the World Clock, Stopwatch, and Screen Lock applications. In addition, the earphones plug were smaller.

iPod mini:

The mini had a smaller structure and it resembled the earlier versions in its features. but it did not support third party accessories. They introduced micro-drive hard drive as the storage medium. The minis were futher improvised as the first generation and second generation devices. It had rich case colors and was a big hit in the market.

iPod shuffle:

Flash memory was introduced through these gadgets, but they did not have a screen so navigation of music files were a little difficult. But it has been reviewed as the best sounding audio device in comparison with the other models.

iPod nano:

iPod nano also had the flash memory but it came with a color display. It also included a number of features like world clock, stop watch and screen lock options.

Keeping Your Computer Clean

2011-09-09T02:43:00.000-07:00

If your computer is used a lot and keep it on for hours at a time it's a good idea to clean it every now and again, one of the main problems is dust. Cleaning out this dust can extend your computers life and make keep it running faster and quieter.

If you have a desktop computer then the main place dust accumulates is around the CPU unit and fan areas. To prevent your processor from over heating there is a fan connected to a heat sink which sits on top of the processor to disperse the heat. This fan blows air down on to the heat sink to cool it down as the heat is passed up from the CPU. Because the fan is constantly blowing air it also blows the dust particles in the air in to the heat sink, over time this can clog up the computers heat sink reducing its effectiveness. Because of the dust your fan may have to blow faster making it louder and more costly to run. Normally you can see if the fan is clogged up simply by opening your computer up and looking at it. If your fans heat sink is really clogged up with dust and dirty looking it is a good idea to give it a clean. When dealing with the inside of your computer or anything electrical ensure the power is turned off and it is unplugged first.

The best way to clean out the insides of your computer is by using a can of compressed air and special nozzle, you can buy these from any good computer store. The spray nozzle is useful for getting in to those tricky places. When spraying the compressed air on to your computer, make sure you don't spray it for to long as condensation may form some drops of water. After blowing away any dust from your computers heat sinks give it a gentle wipe over with an anti-static cloth. You can also use the compressed air to clean your power unit and keyboard.

Cleaning the inside of your computer doesn't take long providing you have the correct equipment, and once done you notice an immediate improvement in your computers performance. The fan wont need to blow as hard so it will be quieter and thanks to the processor running at a cooler temperature your whole computer should generally run faster. I try to clean my computer every 4 or 5 months to keep it running efficiently.

Most often used carbonless paper roll for multiple part forms.

2011-09-07T23:00:00.000-07:00

Manufacturer and exporter of Paper rolls as Carbonless Paper roll, course recorder Paper, atm roll, thermal Paper roll, credit card machine roll and metallized Paper.

We are a trusted manufacturer, exporter and supplier of coated paper like carbonless copy papers, thermal papers and carbonless printer papers. These papers give clear and crisp images all through out. These papers are highly suitable for computer stationery, bank pay-in-slips, credit card charge slips, airway bills and a host of commercial business documents. The Carbonless Paper is offered in the form of reels and sheets. Reels are available in different sizes from 8"to 38" as per the requirements of the customers. Sheets are available in different sizes from 18"x 23", 18"x 24" or any other size as required. Our papers are available in white, pink, green, blue and yellow colour. Carbonless paper uses a chemical reaction between two different contacting coatings to transfer an image when pressure is applied. A paper that is most often used for multiple part forms, it contains a chemical coating on the front side (designated as CF) or on the back side (designated as CB), or on both sides (designated as CFB). When a handwritten or machine impression occurs on the first sheet of multiple parts, the impression transfers from one page or ply to the next due to the bursting of tiny microcapsules in the chemical coating used to release a darkened copy of the impression occurring on the first sheet. A method and apparatus are provided for producing a foam wrapped package for protecting a roll of pressure-sensitive carbonless copy paper. Interleaved foam and film are wrapped under tension around the outer periphery of the roll of carbonless paper by selectively rotating the roll and separately feeding packaging foam and stretch film toward the rotating roll. The present invention relates to a process for producing a foam wrap package, and, more particularly, to a process for wrapping and protecting a roll of pressure-sensitive carbonless copy paper by simultaneously wrapping interleaved layers of stretch film and packaging foam onto the roll of carbonless paper.

Passing The CCNA And CCNP: Cisco Home Lab FAQ

2011-08-15T17:29:00.000-07:00

There is a real revolution today among CCNA and CCNP candidates. More and more of you are turning your back on "router simulators" and putting your own CCNA and/or CCNP Home Lab together, which is the best way to totally prepare to pass these tough Cisco exams.

I get hundreds of emails every month from CCNA and CCNP candidate who are putting together their first lab or adding to their existing one. I'm always glad to help with suggestions, and I thought I'd list five common questions regarding home labs here.

Do I have to spend thousands of dollars?

No! There are vendors all over the web, as well as on ebay, who sell used Cisco routers and switches to Cisco exam candidates like you every single day. They sell kits that consist of multiple routers and switches, as well as single routers and switches. You can add one piece at a time, or make a larger investment. You can spend just a few hundred dollars and put together a very nice lab.

What's an "access server"?

It's not what it sounds like. When I first heard the term, I thought of a typical server like we see in LANs every single day. An access server is actually a Cisco router that allows you to connect to multiple other routers and switches without continually moving the rolled cable around.

You don't have to have an access server right away, but once you add a few more routers and switches to your lab, you'll get tired of moving the rollover cable from console port to console port. (The console port is used to directly connect your PC to the router.) You'll find an access server is easy to set up and configure, and will save you quite a bit of time.

What's a "frame relay switch"?

Again, it's not quite what it sounds like. A frame relay switch is not a switch; it's a Cisco router that has been configured to serve as a frame relay provider in your home lab.

This is very close to being a "must" for your home lab. You don't need it right away if your budget allows for only one or two routers to get started. To truly practice frame relay map statements and see the effect of different frame relay statements, you'll need a Cisco router to serve as a frame switch. Again, the configuration is easy, and having a frame relay switch in your home lab will give you practice that will be invaluable on exam day.

Do I need a switch? What switch should I buy?

I recommend you get at least one switch in your lab; two if your budget allows. Make sure that at least one of your switches has an IOS; 1900 switches do not have an IOS and while they're better than not having a switch, they're not going to give you the practice you need to pass the CCNA and CCNP. Look to the 2500 family of switches.

I want to build my CCNP lab and then use it for the CCIE. What should I buy?

It's impossible to tell what technologies and devices will be on the CCIE lab, even if you zip through the CCNP and then take the IE within six months. Cisco refreshing the CCIE lab blueprint every six months, and different technologies can be taken off the lab. While Cisco gives plenty of notice that these changes are going to take effect, it can be a big pain in your wallet if Cisco takes something off of the exam after you spend a bundle to add it to your lab.

As an example, Cisco is in the process of removing ISDN and ATM from the CCIE Routing & Switching lab. If you bought an ATM switch for your lab, you've got an expensive paperweight right now. While you may be able to practice your core protocols on a CCIE home lab, it's going to be difficult and expensive to keep your home lab totally current with the Cisco lab blueprint.

The decision to put together your own CCNA or CCNP home lab is the best decision you can ever make - and I speak from experience. With home labs becoming less expensive every day, it's becoming more affordable as well. Start looking into used Cisco router vendors today (ebay is a great place to find some vendors, as is Google), and you can be practicing on REAL Cisco routers and switches soon - and be totally prepared for CCNA and CCNP exam success.

Protect Your Computer With Zone Labs

2011-08-14T09:09:00.000-07:00

Zone Labs is the most trusted name in Internet security, and with good reason. The Zone Labs products are effective at keeping computers protected from spyware, hackers and other Internet bad guys without clogging up your system.

They're also easy to install and configure to meet your needs. Zone Labs' products offer a range of services depending on what you need and want from an Internet protection program.

ZoneAlarm, the most basic firewall program offered by Zone Labs, can be downloaded for free and used for personal, non-business use.

ZoneAlarm Antivirus adds the Zone Labs triple-defense firewall, antivirus protection, e-mail security and protection for your wireless network.

Zone Labs' ZoneAlarm Anti-Spyware offers the same features as the antivirus program except with anti-spyware protection instead of antivirus.

The added power of ZoneAlarm Pro includes Zone Labs' identity theft and privacy protection programs, e-mail security and anti-spyware.

The all-in-one solution from Zone Labs is ZoneAlarm Internet Security Suite, which includes the basic and triple defense firewalls, anti-spyware, antivirus, identity theft and privacy protection, anti-phishing and spam blocker, e-mail security, instant messenger security, parental controls and protection for wireless PCs.

You can also buy the instant messenger security and parental controls separately from Zone Labs in the product IMsecure Pro.

These products from Zone Labs can give you peace of mind as they protect your computer from a variety of problems you don't want to have. Zone Labs can protect you from hackers, spam, viruses, identity theft and more. Stop these menaces before they get to your computer and your information, with a little help from Zone Labs

Zone Labs is the trusted leader in Internet protection and personal firewall systems. More than 30 million computers worldwide are trusted to Zone Labs products. And it couldn't be easier to protect your computer from all of the various threats that are out there when one Zone Labs product can do it all for you.

The Zone Labs products are easy to install and use but still very powerful. They allow customers to protect themselves without a lot of effort or thought on their part. Zone Labs also allows more knowledgeable users to fine-tune the settings on their products to give them exactly what they need from the firewall and Internet protection package.

If you need technical help when working with any product from Zone Labs, you can find support online, via e-mail and through the ZoneAlarm Support Center. Zone Labs is there with you to help make your Internet systems work for you and protect your computer in the best way possible.

There's no better feeling than being able to get online and know that your computer is safe from viruses, hackers and identity thieves. Zone Labs can give you that kind of security.

Television Tuners, Making Television on your Computer Possible

2011-08-13T19:19:00.003-07:00

Television tuners allow a user to watch television on their computer monitor. There are several different types of television tuners which we will discuss in this article.

The most common type of television tuner for a computer is the USB television tuner. USB ports are common on all computer so this type of connectivity make it possible to connect the tuner to pretty much any computer.

The television tuner acts just like a normal television would but with the need for a bulky antenna. USB television tuners can receive standard definition, or high definition signals depending of the type of tuner you have.

Most television tuners are bundled with some sort of software. This software allows the user to record the streaming television onto their computer so they can watch programs at a later date. In most cases this software is easy to use and easily setup.

Television tuners are constantly evolving. The newest wave of television tuners allow the user to use two streams from the one tuner. Meaning, you can record one television show while watching another. This is very convenient but at present, only one stream can be recorded and the recorded stream cannot be viewed in conjunction with the non-recorded stream.

Television tuners are a great way to watch television on notebook computers. With the portability of notebook computers, watching television anywhere your notebook can go is possible.

Television tuners can be bought for different prices depending on the quality of the product and the features/software they provide. A simple tuner can be bought for around 50 dollars whereas a more expensive alternative with more comprehensive software will cost upwards of 100 dollars.

With portability becoming more and more of an issue with today's consumers, a USB television tuner is a great solution to watching television from your computer.

Digital Projector Guide- Some tips for Digital Projectors

2011-08-13T17:24:00.001-07:00

Digital projectors are equipments of modern technology. These are used to convert image data directly from the computer onto a screen via lens system. Digital projectors provide visualization of data that is actually stored in a computer for presentation. These projectors enable the viewers to watch moving images from a DVD, digital versatile disc player. Advertisers or sellers also use these projectors to give demonstration of products to a large number of customers. It can easily convert written documents onto an interactive whiteboard.

Digital projectors play an important role in the formation of home theater systems. These projectors use resolution of SVGA standard i.e. 800×600 pixels in expensive devices. Cost of digital projector is determined by its resolution as well as its brightness. If you're going to use it in large rooms or big conference halls its brightness should be from 1,000 to 4,000 ANSI lumens.

First digital projectors, Eidophor projectors were introduced in 1950. Eidopher projectors used an oily surface in a rotating disk with light shining through it and employed an electron beam to disrupt oil in a specific manner. Eidophor projectors were not able to produce colors. Nowadays there are several high quality models of digital projectors are available in market so Eidopher projectors are less common.

Following four technologies are used in digital projectors:

High intensity CRT

LCD projectors using LCD light gates

Texas Instruments' DLP technology

Eidophor oil-film projectors (obsolete)

At present LCD projectors use Texas Instruments' DLP technology whereas the high intensity CRT devices are suitable for enduring installations. Entire working of cathode ray tube digital projectors is like CRT television set. These projectors may be configured with one RGB color tube that has three colors red, green and blue with a single lens, one black & white tube with a rotating color wheel or three RGB color tubes with three lenses.

Projectors having cathode ray tubes are usually bulky thats why these are the best projectors for fixed installations.

LCD digital projectors are portable and lighter enough in comparison to CRT and can be easily shifted from one place to another. These are very much popular and available in various shapes and sizes. CRT and LCD digital projectors come under the category of transitive projectors.

Reflective projectors are the superior digital projectors that provide high quality images. These are affordable and offer next level of entertainment. Everyone can enjoy home theater applications with the help of digital projectors.

What is Computer Virus?

2011-08-12T09:30:00.000-07:00

A computer virus is an executable program. Depend on the nature of a virus, it may cause damage of your hard disk contents, and/or interfere normal operation of your computer.

By definition, a virus program is able to replicate itself. This means that the virus multiplies on a computer by making copies of itself. This replication is intentional; it is part of the virus program. In most cases, if a file that contains virus is executed or copied onto another computer, then that computer will also be "infected" by the same virus.

A virus can be introduced to a computer system along with any software program. For Internet users, this threat can come from downloading files through FTP (file transfer protocol), or referencing email attachments. (Please refer to our web page on Handling Email's File Attachments for details.)

When a virus is introduced to a computer system, it can attach itself to, or sometimes even replace, an existing program. Thus, when the user runs the program in question, the virus is also executed. This usually happens without the user being aware of it.

A virus program contains instructions to initiate some sort of "event" that affects the infected computer. Each virus has an unique event associated with it. These events and their effects can range from harmless to devastating. For examples:

· An annoying message appearing on the computer screen.

· Reduced memory or disk space.

· Modification of data.

· Files overwritten or damaged.

· Hard drive erased.

Finding Your MAC Address On Wired And Wireless Network Cards

2011-08-11T09:56:00.000-07:00

Over the past few weeks I have received quite a few e-mails about Ethernet cards, both wired and wireless, and more specifically, about Media Access Control (MAC) addresses. I think the main reason I've received so many questions about Ethernet cards and MAC addresses is people trying to secure their home wireless networks and their desire to use MAC address filtering. This type of filtering in wireless networks can be configured to allow or deny specific computers to use or attach to the wireless network, based on the MAC address.

My first thought was to write an article just about MAC addresses and wireless Ethernet. After thinking about it I decided to expand on this and go over some specific information about Ethernet cards and communication.

Different Ways Of Finding Your MAC Address And More
--------------------------------------------------
There are several ways of finding your Ethernet and communications protocol information. Many Ethernet card manufacturer's have proprietary software that can reveal this information but they work differently depending on the manufacturer. So we will use the Windows 2000 and XP "ipconfig" utility since this is available in the majority of Windows Operating Systems.

First, go to "start" -> "run" and type "cmd" without the quotes. Then hit the enter key. At the command line type "ipconfig /all", again without the quotes. Actually, just typing ipconfig without the /all will work but will only provide you with abbreviated information regarding your network cards. An example of what you might see by typing the "ipconfig /all" command is below with each item commented in green lettering:

Fault Tolerant And Highly Availability Computer Systems
----------------------------
There are several ways of finding your Ethernet and communications protocol information. Many Ethernet card manufacturer's have proprietary software that can reveal this information but they work differently depending on the manufacturer. So we will use the Windows 2000 and XP "ipconfig" utility since this is available in the majority of Windows Operating Systems.

First, go to "start" -> "run" and type "cmd" without the quotes. Then hit the enter key. At the command line type "ipconfig /all", again without the quotes. Actually, just typing ipconfig without the /all will work but will only provide you with abbreviated information regarding your network cards. An example of what you might see by typing the "ipconfig /all" command is below:

OutPut Of The "Ipconfig /All" Command
----------------------------------------------------------
Windows IP Configuration

Host Name . . . . . . . . . . . . : Home Computer
This is the name of your computer, typically defined during the windows installation. However, it can be changed after installation.

Primary Dns Suffix . . . . . . . : domain.com
If your computer participates in a network such as a Microsoft Windows domain this item may contain the name of the domain.

Node Type . . . . . . . . . . . . : Unknown
The Node Type may say Unknown, or peer-to-peer, or in some cases "hybrid". It is a setting that has to do with the Windows Internet Naming Services used in certain types of Windows domain networks.

IP Routing Enabled. . . . . . . . : No
This setting determines if Windows XP or 2000 will function as an IP router. If you have two or more network cards you can setup your system to act as a router, forwarding communications requests from one network to another. Windows 2000 can be configured to do this in a pretty straight forward fashion; Windows XP will need a registry modification.

WINS Proxy Enabled. . . . . . . . : No
WINS Proxy is another setting that is related to the "Node Type" we discussed earlier. It is normally not a required setting in a home or small office network, or newer types of Microsoft Windows domains.

Ethernet adapter Wireless Network Connection 2:
If you have multiple Ethernet (network) cards in your systems, as I do in this laptop, you will have multiple listings. This one happens to be the second Ethernet card, an internal wireless Ethernet card.

Description . . . . . . . . . . . : Broadcom 802.11b/g WLAN
This is the description of the Ethernet card, usually the Name / Manufacturer and type of Ethernet card. In this case, it is a Broadcom wireless Ethernet card built into my laptop.

Physical Address. . . . . . . . . : 00-90-4B-F1-6E-4A
And here we have the MAC address. The MAC address is a 48 bit hexadecimal code and is suppose to be a totally unique address. It is 48 bits because each number or letter in hexadecimal represents 8 bits. Hexadecimal numbers range from 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E, F. There are 6 alpha-numeric codes hence 6*8=48(bits). The first 3 codes identify the manufacturer of the card and the remaining codes are used to create a unique number. Theoretically there should never be a card with same MAC address on a local network. However, there are a few exceptions. There are software tools that allow you to change this code. In fact, this is a step some hackers take to attack other systems on a local network. I say local network because MAC addresses are not routable between network segments. By spoofing this address, you can impersonate another machine on the local network. Traffic that was bound for the intended target can be redirected to the hacker's machine. This is the address you would also use to populate a MAC address, or physical address table when setting up your wireless access point to support MAC address filtering.

DHCP Enabled. . . . . . . . . . . : Yes
DHCP, or the Dynamic Host Control Protocol, if enabled means your computers IP address is being provided by a DHCP server on you network. The DHCP server could be your wireless access point, cable/dsl router, cable modem, or a server on your network. Also, if a DHCP server is not enabled on your network, your computers Operating System will auto generate a random IP address within a certain predefined range. This means you could network a group of systems together without having to manually assign the IP settings.

IP Address. . . . . . . . . . . . : 192.168.0.117
This parameter provides you with your current IP address. The address listed above is what is called a "private" address. There are certain classes of IP addresses that have been set aside for private use. This means for your internal, local, or private network at home or office. These addresses are not, or should not, be routable on the Internet. The Internet routes what are called "valid" IP addresses. Your cable/dsl router or cable modem has a valid IP address assigned to its "external" network interface. The external interface may be your phone line or cable TV cable.

Subnet Mask . . . . . . . . . . . : 255.255.255.0
The Subnet Mask is a special number, or in some sense, filter, that breaks down your IP address, in this case private IP address, into certain groups. IP addresses and Subnet Masks can be a complicated matter and would take an entire article to go over.

Default Gateway . . . . . . . . . : 192.168.0.254
The default gateway, the IP addresses listed above, is the IP address of the device that will route your request, such as when you try to browse a website, to the Internet. It is a bit more complicated than that though as gateways or routers can route traffic to various different networks, even other private networks. At your home or small office, this gateway most likely is your cable/dsl modem or router.

DHCP Server . . . . . . . . . . . : 192.168.0.49
The DHCP server, remember we talked a little about this above, is the device that assigns your computer an IP address and other information. DHCP servers can assign all kinds of information such as; Default Gateway, Domain Name Servers (DNS), IP address, Subnet Mask, Time Server, and much more.

DNS Servers . . . . . . . . . . . : 192.168.0.49, 64.105.197.58
DNS Servers are internal or external servers that resolve Fully Qualified Domain Names (FQDN), such as www.defendingthenet.com , to IP addresses. This is done because computers don't actually transmit your requests using the domain name, they use the IP address assigned to the FQDN. For most home or small office users, the primary DNS server is the IP address of your cable/dsl router. Your cable/dsl router than queries an external DNS server on the Internet to perform the actual resolution of the FQDN to IP address. The address 192.168.0.49 is an internal private device on my network whereas the 64.105.197.58 is an external public Internet DNS server and is present just in case my router has trouble performing the DNS resolution tasks.

Lease Obtained. . . . . . . . . . : Sunday, March 19, 2006 6:38:16 PM
This information tells you when your computer received its IP address and other information from a DHCP server. You will notice it says "Lease Obtained", that is because most DHCP servers only lease the IP address to you from a pool of available address. For instance, your pool may be 192.168.1.1 through 192.168.1.50. So your DHCP server has 50 IP addresses to choose from when assigning your computer its IP address.

Lease Expires . . . . . . . . . . : Wednesday, March 29, 2006 9:38:16 PM
When the IP address, assigned by the DHCP server, lease expires it will attempt to lease you the same or another IP address. This function can typically be changed on the DHCP server. For instance, on some fully functional DHCP servers, you can configure the Lease to never expire, or to expire within 1 day and so on.

Why Are MAC Addresses So Important And How Do They Work
------------------------------------------------------
To jump back to MAC address for just a bit. You may think that IP addresses are the most important thing when it comes to network communication. The reality is, MAC addresses are very important because without them computers would not be able to communicate over Ethernet networks. When a computer wants to speak with another computer on a local network, it will make a broadcast request, or ask a question, of who owns a particular IP address. For instance, your computer may say "Who is 192.168.0.254". Using the information above, my default gateway is 192.168.0.254 and will answer "I am "00-90-4B-F1-6E-4A" 192.168.0.254". It sends back its MAC address. That MAC address then goes into what is called a Address Resolution Protocol (ARP) table on your computer. You can see this information by going to the command prompt like you did above and typing "arp –a". You will get information like the following:

Internet Address Physical Address Type
192.168.0.49 00-12-17-5c-a2-27 dynamic
192.168.0.109 00-12-17-5c-a2-27 dynamic
192.168.0.112 00-0c-76-93-94-b2 dynamic
192.168.0.254 00-0e-2e-2e-15-61 dynamic

How A Hacker Can Use MAC Addresses In An Attack
----------------------------------------------
You will notice the IP addresses and to the right of them the MAC addresses. Without this information, without the MAC address, you would not be reading this article right now. MAC addresses are not routable like IP addresses. They work on your local or private network. However, devices on the Internet perform the same tasks. Routers and switches maintain a list of their peer devices MAC address just like your computers and devices on your home or office network. I mentioned above that MAC addresses can be changed in order to redirect requests. For instance, if I were on your office network and you had an internal web server that took personal information as input, I could tell your computer to go to my laptop for the web site by broadcasting my MAC address tied to the real web servers IP address. I would do this when you computer asked "Who is the "Real Web Server"". I could setup a fake web server that looks just like the real thing, and start collecting information the real web server would normally collect. You can see how dangerous this can be.

Conclusion
-----------
There are several other easy ways you can find your MAC address but they can be a little confusing if you have more than one internal network card. Most external USB, or PCMCIA wired and wireless Ethernet cards have their MAC address printed on them. In cases where the wired or wireless network card are inside your computer, such as in laptops, the MAC address is sometimes printed on the bottom of the laptop. Even Desktop systems cards that are inserted in PCI slots have the MAC address printed on the Ethernet card.

You may reprint or publish this article free of charge as long as the bylines are included.

Original URL (The Web version of the article)
------------
http://www.defendingthenet.com/NewsLetters/FindingYourMACAddressOnWiredAndWirelessNetworkCards.htm

About The Author
----------------
Darren Miller is an Information Security Consultant with over seventeen years experience. He has written many technology & security articles, some of which have been published in nationally circulated magazines & periodicals. If you would like to contact Darren you can e-mail him at Darren.Miller@defendingthenet.com. If you would like to know more about computer security please visit us at http://www.defendingthenet.com.

How to recover lost photos

2011-08-10T18:28:00.000-07:00

t happens all too often. You're downloading your latest snaps from your digital camera, and the computer freezes. After you restart and try again, there appear to be no pictures in the camera. Or perhaps the photos were on your hard drive and you deleted them accidentally, or you didn't have a backup and your hard drive failed.

Whatever the cause, there is no reason to panic. The computer may no longer be able to find your pictures, but it's unusual for a fault to completely wipe them from the storage card or disk. With the aid of some inexpensive data recovery software, you're almost certain to be able to get your photos back.

There are many data recovery programs on the market, but for photo recovery I strongly advise using software specifically designed to recover digital images. This kind of software has several benefits, not least the ability to show a preview of every recovered image. Often, data recovery tools find files that look like they might have been a digital image, but aren't. The preview feature saves you wasting time recovering files that turn out to be junk.

Another advantage of specialised photo recovery software is that it looks only for photo image file types. It knows what JPEG and other image files look like on disk. This improves the chances of a successful recovery, and reduces the number of junk files that are found.

Modern data recovery software is easy enough to use that anyone can do it. You just start the software and tell the program where the drive containing the missing images is. The software scans the drive looking for the patterns that it recognizes as photo image files. When it has finished, it will display a list of files, with thumbnail images showing the content. All you have to do is select the photos you want to recover, and safe them to a safe place on your hard disk.

Router - Transmitting Packets

2011-08-09T19:41:00.000-07:00

In a previous article we discussed the basics of what a router did. We're now going to get into a more detailed, and yes technical, explanation of how packets are transmitted as well as a few other tech specs of how routers work. So put on your learning caps because you're in for a real mind bender.

Internet data, whether it be in the form of a web page, a downloaded file or an email message, travels over what is called a packet switching network. Basically what happens is that the data is broken up into individual packets because there is only so much data that can be transmitted at one time. Each packet is about 1500 bytes long. Each packet contains quite a bit of information including the sender's address, the receiver's address and of course the information being sent which includes the order of each packet how it should be put back together so that the end user can make sense of the data. The packet is sent off to its destination based on what the router believes to be the best route to follow, which is usually the route with the least amount of traffic and if possible, the shortest route. Each packet may actually given a different route depending on conditions at the time, which in a high traffic network can change every second. By doing this, the router can balance the load across the network so that no one segment gets overloaded. Also, if there is a problem with one piece of equipment in the network, the router can bypass this piece of equipment and send the packet along another route. This way if there is a problem, the entire message will still arrive intact.

In conducting this process, routers have to speak to each other. They tell each other about any problems on the network and make recommendations on routes to take. This way, paths can be reconfigured if they have to be. However, not all routers do all jobs as routers come in different sizes and have different functions.

There are what we call simple routers. A simple router is usually used in a simple small network. Simple routers simply look to see where the data packet needs to go and sends it there. It doesn't do much else. Slightly larger routers, which are used for slightly larger networks, do a little bit more. These routers will also enforce security for the network, protecting the network from outside attacks. They are able to do a good enough job of this that additional security software is not needed. The largest routers are used to handle data at major points on the Internet. These routers handle millions of packets of information per second. They work very hard to configure the network as efficiently as possible. These are stand alone systems and actually have more in common with supercomputers than with a simple server one might have in a small office. In our next instalment we'll look at how to actually trace the path that a message has taken and some examples of transmitting packets.

How To Recover Lost Data

2011-08-09T10:20:00.001-07:00

Computer files are a lot more important to some people than their lives because it represents their whole life's work and achievement. There are people who rely on their computers for almost everything, from their daily schedules, business and personal files and what have you. The possibility of losing their computer data is thus a horrifying thought for them.

Even a student who uses his computer to store assignments, research papers and other school data will be dismayed at the though of losing such files. What more for a computer dependent entrepreneur who relies on his computer for the day to day existence of his business. Losing computer data for both types of computer users would mean a catastrophe because once lost, computer data can no longer be recovered.

However, technological advancements have made data recovery possible depending on a lot of factors. For one, computer users are advised to make back ups of their computer data to make sure they would not be caught red handed when computer data is destroyed. For some who hold very important computer data, the back up itself should even be further backed up to make sure there is a way of recover lost data.

Fortunately, there are companies who offer data recovery services in case of an unforeseen disaster like corruption of files or crashing of a computer hard drive. People who store very important data in their computers need to have back ups but in any case, they should be acquainted with a computer company that can offer them fast and efficient services for the recovery of their lost computer data

It is thus pertinent that computer users have a way of knowing where to contact computer companies who can recover lost data for them no matter how such data was lost. There are various ways of losing precious data and one of those is carelessness. People take for granted that computers are very fast and efficient machines they can accidentally command their computers to lose or delete data in a flash.

The widespread use of internet has also been responsible for thousands of computer crashes all over the world because of viruses that attack computer hard drives. There are plenty of technical reasons why data is lost. Added to that are unforeseen disasters like fire or other calamity.

Computer users who have backed up their lost data but who discover that their back ups do not work still have a recourse. Rest assured that there are companies and software that can recover your computer files efficiently and quickly to minimize your potential losses.

Companies providing data recovery are equipped with technical people who around the globe and are more than capable of bringing back lost data. You just have to be able to know them beforehand so that when your computer data gets lost or destroyed then you have immediate access to their services.

Wireless Networks: How Do They Work?

2011-08-09T10:18:00.001-07:00

Wireless networks use radio waves instead of wires to transmit data between computers. Here's how:

The Binary Code: 1s and 0s

It's well known that computers transmit information digitally, using binary code: ones and zeros. This translates well to radio waves, since those 1s and 0s can be represented by different kinds of beeps. These beeps are so fast that they're outside the hearing range of humans.

Morse Code: Dots And Dashes

It works like Morse code, which is a way to transmit the alphabet over radio waves using dots (short beeps) and dashes (long beeps). Morse code was used manually for years via telegraph to get information from 1 place to another very quickly. More importantly for this example, though, it is a binary system, just as a computer system is.

Wireless networking, then, can be thought of as a Morse code for computers. You plug in a combined radio receiver and transmitter, and the computer is able to send out its equivalent of dots and dashes (bits, in computer-speak) to get your data from here to there.

Wavelengths And Frequencies

You might wonder how the computer can send and receive data at high speed without becoming garbled nonsense. The key to wireless networking is how it gets around this problem.

First, wireless transmissions are sent at very high frequencies, which allows more data to be sent per second. Most wireless connections use a frequency of 2.4 gigahertz (2.4 billion cycles per second) -- a frequency similar to mobile phones and microwave ovens. However, this high frequency produces a wavelength that is very short, which is why wireless networking is effective only over short distances.<

Wireless networks also use a technique called "frequency hopping." They use dozens of frequencies, and constantly switch among them. This makes wireless networks more immune to interference from other radio signals than if they transmitted on a single frequency.

Internet Access Points

The final step for a wireless network is to provide internet access for every computer on the network. This is done by a special piece of wireless equipment called an access point. An access point is more expensive than a wireless card for 1 computer, because it contains radios capable of communicating with around 100 computers, sharing internet access among them. Dedicated access points are necessary only for larger networks. With only a few computers, it is possible to use 1 of them as the access point, or to use a wireless router.

Industry Standards

Wireless equipment from different manufacturers can work together to handle these complex communications because there are standards which guide the production of all wireless devices. These standards are technically called the 802.11. Because of industry compliance with these standards, wireless networking is both easy to use and affordable today.

Wireless Is Simple To Use

If all this talk of frequencies has you worried -- relax. Wireless networking hardware and software handle all of this automatically, without need for user intervention. Wireless networking, for all its complicated ability, is far simpler to use than you might expect.

High Definition Tuners

2011-08-09T10:16:00.000-07:00

High definition TV tuners or HDTV tuners are designed to receive high definition programs by connecting to an external antenna. HDTV tuners will not only show movies and DVD's at high definition, but will improve the viewing of normal TV. It is because of the improved definition or color and picture quality of DVD's and programs that make HDTV tuners very popular with viewers.

Television sets often come with HDTV tuners already built into them, these are called integrated HDTV's. If you are considering buying an external high definition TV tuner for your television, make sure that your TV set is HDTV compatible. A separate tuner may also be needed. This can be either a cable or satellite box for watching high definition programs.Most people have heard that there is a mandate on televisions to make integrated HDTVs. This is not entirely correct. Certain televisions that are for sale after a certain date will be required to have built in tuners. The tuners required won't be HDTV. The mandate is actually referring to ATSC tuners. It is not even necessary that TV's be able to display HDTV resolutions without either an internal or external tuner. This new mandate will not apply to plasma and front projectors. The mandate will not take effect for some time. Until then there will be no change in television manufacture or tuners.

It is important to ask about features of high definition TV tuners before making a choice. If you are not sure what some of the features are, ask for clarification. Make sure that your television is compatible, HDTV tuners may not work with older televisions. Ask your cable or satellite company weather they support high definition TV, as many people find out later down the road that they cannot receive HDTV programs through cable or satellite.

Ask about what kind of warranties are available and what parts they actually cover before buying. External high definition TV tuners are quite reasonably priced. Prices start at around $150. If you are on a budget, make sure not to buy cheaply made appliances. Always wait for specials or price reductions on reliable brands.One of the most popular brands available is the Samsung SIR-T451. This one is ideal for high definition programming on any high definition TV compatible television. There are many more HDTV tuners available on the market. By doing a quick search on your favorite search engine, you will be able to find a HDTV tuner that will fit both your budget and your TV's requirements.