The way LulzSec put their exploits out in the open is new, and it should serve as a wakeup call to the general populace that system security needs to be taken much more seriously. It isn’t a secret to I.T professionals that hacks occur on a frequent basis. Yet it tends to be in the best interest of the victims to keep break-ins under wraps. While some companies are slowly developing policies to alert their users, if a compromise doesn’t legally dictate that the company must disclose the event, it remains likely that they will not; there is little to be gained, and much to be lost, by letting the world know that your systems are not secure.

Indeed, what LulzSec has shown us that the systems of major corporations are not secure. We will never know how many of the affected companies would have confessed to the public that they were hacked. We do know that Sony was not eager to come clean (it is curious to wonder whether this dishonesty is what made Sony such a popular target for the hacker group). We will also never know how many similar breeches occur on a daily basis, committed by hacker groups less eager to be in the spotlight, or whether LulzSec divulged all their attacks. There may be compromised systems they haven’t told us about.

What we do know for certain is that for fifty days, a small group of hackers penetrated numerous corporate networks and denied service to many more, and remains almost completely unmolested by law enforcement. Even after they breached the FBI, Air Force, and CIA, the governments of the world seemed powerless to put a stop to it. The only ones able to counter attack, it seems, is other hacker groups.

This is a serious problem for everyone involved. If law enforcement is unable to put a stop to widely-publicized attacks, they surely won’t be able to fight hackers who keep their exploits under wraps. Logically, if a hacker targets a network for profit (say, a credit card processing system), he isn’t going to brag about it to all of twitter or post the contents on Bittorrent. We can’t know how often this occurs, but we can infer from the past few weeks that when it does, the perpetrators likely won’t face any repercussions from the police.

Additionally, the ease with which LulzSec exploited these networks is frightening, to say the least. Unfortunately, it is difficult for the general public to appreciate the meaning of compromises via SQL injection; but this type of vulnerability, especially in a network of a company such as Sony, is worrisome. If Sony cannot maintain a higher standard for coding practices, we have to ask what level of security auditing other companies are performing on their networks. The fact that one of the LulzSec releases is a list of routers on the Internet that are still using default usernames and passwords is just another example that people simply aren’t taking network security seriously enough.

Unfortunately, I fear that with LulzSec breaking up, its members won’t feel as free to publish their exploits on the Internet. The constant bombardment of compromises will continue, but they will cease to appear as headlines on the nightly news. This falling out of the public eye might just be the absolute worst thing that can happen at this point. We need to be pressuring our governments and our businesses to take security seriously – or none of us will be safe.

While the Sony Internet TV is pretty cool right now, we’re still only in the first generation of the device. It’s clear that there’s a lot of unlocked potential here, and that there are revenue streams down the road which Google and content providers are going to be quick to grab. Here are some things you should expect to see coming to internet-enabled televisions in the near future:

1. Extremely targeted advertizing

Let’s get the obvious out of the way first: there’s nothing stopping Google from knowing that you’re watching the fashion channel, and serving you up an advertisement for the exact dress or suit that’s being modeled on the screen at that moment. When you’re watching a sporting event, you should expect that you’ll start seeing ads for your favorite team’s merchandise. Or, if you’re watching the food network, you might get a adwords-style link saying “click here for more recipes.” This doesn’t exist yet, but I have to imagine it will soon.



Having an internet-connected, interactive television is one step toward doing away with the conventional shotgun approach of 15/30/60 second one-size-fits-all commercials, which has been the television advertising model for decades. There’s a reason that Google is entering this market place – it’s to serve you up extremely targeted ads, and to make money off those clicks and purchases.

2. Games via the marketplace

A Sony representitive I spoke to said that the Android Marketplace is scheduled to go live for the Sony Internet TV some time in 2011. When that happens, the TV will instantly become its own video game console. Since these televisions come with USB ports, it isn’t much of a stretch to get a video game controller working (right now it supports a regular keyboard and mouse).

While I don’t think this poses any threat to the existing high-end console market, it certainly presents a great opportunity for developers. Until now, the television has been a popular gaming platform, but the cost of entry was too high to develop for the Xbox or PlayStation. Now that the television runs Android, it’s an entirely different ballgame.

3. Rampant piracy from rooted devices

It’s just a matter of time before people start rooting these devices. Once that happens, it opens up the possibility of installing a bittorrent (or another p2p network) client directly on your television. Since the program is running on the TV itself, and because it can integrate with the Android operating system, it should be possible to make pirated media as easy to access as legally-obtained content.



One has to assume that this was considered by Sony, since they provide both the platform (the television) and the content. Perhaps it was decided that piracy is an inevitable factor that will have to be dealt with, and that they could not afford to delay their entry into the market. However, the cable companies and content providers, as the party with the most to lose, might not be so eager to take the jump (Indeed, this seems to be the case, as several major broadcast companies have blacklisted Google TV.)

4. Immersively Interactive Television

The past few years have seen a proliferation of mildly-interactive TV. Whether it’s a sports game asking you to go to a website to cast a vote for player of the game, or American Idol letting you text a vote for your favorite singer, television is aiming to captivate their audience through interactivity. An interactive audience is an engaged audience, and an engaged audience is a reliable consumer that will come back next week.

Having an internet-connected television means that you can cast a vote for favorite singer or baseball player, directly from the TV. But it also means much more. Imagine the possibilities for off track betting or other gambling services – you don’t have to go to the race track anymore, when you can enter your credit card information directly to your TV. Game shows could bring the audience directly into the hot seat, and a show like Fear Factor could have the viewers pick what kind of torture to force on contestants next. The real interesting things, of course, will be the content that is created specifically for this new interactive medium, not the current shows that will be modified to use the new technology.

There’s likely many more changes that internet-enabled television will bring about; these are only some of the obvious items I’d expect to see in the very near future. It’ll be interesting to see whether the media companies embrace this new technology, or follow their ways of the past of resisting the shift in consumer interest until it becomes obvious that there’s no choice but to accept it.

What do you think? How might an internet TV affect the way you watch and interact with media? Do you have any plans on buying an internet-enabled television, or are you going to wait until the technology is more developed? Leave your responses and opinions in the comment section below!

• A file that moved around on the hard disk

If a file that you want to securely delete now resides on a certain set of sectors on disk, but previously existed on another part of the disk, it’s possible that the old ‘ghost’ copy of the file could still be recovered assuming it hasn’t already been overwritten by other data. The safest way to avoid this is to use a tool to clean all free space on the filesystem (details are in my secure deletion article). If you’re concerned about multiple overwrites, then you’ll have to erase the entire disk — there’s no way of determining the previous location of the file.

• Backups and archives

If a piece of data is important enough that you want to thoroughly delete it, it’s likely that it was important enough to backup at some point. You’ll need to identify any backup or archived copies and make sure to destroy those, too. If they reside on tape or WORM storage, actually going forward with this task might be difficult. If you backup to the cloud, it might be impossible.

• Cache – Disk and Other

There are many layers of cache that have the potential to store data you wish to shred. Web browsers cache to the hard disk in order to improve performance, while word processors (and other office applications) often cache to the hard disk to prevent data loss in a crash or sudden power failure. Additionally, file systems typically have write cache that store data in memory before writing it out to disk, and disks themselves (as well as RAID controllers) are almost always equipped with cache as a method of improving performance. Every one of these cache locations is a potential storage spot for your private data, and if you want to make sure that your secure deletion is truly secure, you’ll have to take them into consideration.

The lesson is that, when you aim to make sure make sure you delete a file such that it can never be recovered, you need to take more into consideration than simply running ‘shred’ against that file. I hope these tips provide some insight into the other things you’ll need to do in order to keep your personal data safe.

Before continuing, it’s important to understand the question being asked. The issue at hand is filesystem journaling. Most commonly-used filesystems today (such as ext3, ext4, and NTFS) all use a journal to record changes to the filesystem before the actual changes are made to the system. This is done to prevent the system from becoming corrupt in the event of an unexpected shutdown (a power failure or a system crash, for example). By recording the planned modifications in a staging area before they are actually made, the filesystem can then play back the journal on the next bootup and maintain a consistent state, if the system goes down uncleanly.

This presents an obvious concern for secure-deletion tools. If data is written to the journal first, then deleting the primary file isn’t going to do the entire job; in theory, the data would still be recoverable from the journal.

The good news is that by default, most filesystems only record metadata to the journal, and don’t write the data until it actually gets pushed out to its final destination. The metadata includes things like the disk sectors, size, attributes, and so forth. This is the most important information for a filesystem to keep, since if the metadata becomes corrupt, there is a risk that the entire filesystem can become corrupt with it. Losing the data inside a file is an isolated data-loss event; losing an entire filesystem is catastrophic.

For performance reasons, most filesystems specifically do not journal actual file data. While journaling this data would almost completely prevent any corruption, it would come at the cost of having to commit every single write to disk twice (once to the journal, and once to its final location on disk). As such, neither ext3, ext4, or NTFS use journaling for actual file data — by default.

Checking the journaling level of your system is very easy. You’ll want to check both what the filesystem is set to use when it is mounted, as well as the currently-running level. To see the default mounting optins in Linux, you’ll want to take a look at the /etc/fstab file.

You’ll notice here that all the main filesystems are set to use the default filesystem settings, and as stated above, ext3 and ext4 do not journal file data by default (for details, see the ext4 documentation at Kernel.org). If someone had set the filesystem to journal file data, you’d see something similar to this:

Notice here how the setting data=journal has been appended to the default settings. When this filesystem is mounted, it will be set to record new data to the journal before writing it to its destination on the filesystem.

Now, take a look at the currently-mounted filesystems by running the mount command:

Notice that the options for each filesystem are displayed on-screen. Here, the text “data=journal” does not appear because none of the filesystems are mounted in this mode (in fact, they are all mounted with their defaults). With data journaling enabled, you’d see something like:

In this case, we see that /home/jdeprizi/funland/funPartition is mounted such that it will journal filesystem data.

Essentially, as long as you’re using the default settings, you’re not journaling the actual file data. Therefore, you don’t have to worry about the journal foiling your secure file deletion. But even if we don’t have to worry about the filesystem journal, are there other areas we have to fear? Come back later in the week for a follow-up on this topic, covering some of the other items that you need to take into consideration when you want to securely and completely delete a file. I invite you to subscribe to the RSS feed or newsletter to receive automatic updates when new articles come out, and to leave a comment below with any questions you have about this or any other topic.

First up is a pair of stories that your web browser is soon going to have hardware graphics acceleration. In yet another sign that the browser wars are getting hotter than ever before, both Chrome and Firefox are going to be sporting GPU support in near-future versions. I recently wrote that pure speed is one of the reasons for Chrome’s success, so it will be interesting to see how much ground Firefox can gain on the performance end by introducing this technology.

This week we saw two very important players leave Oracle after that company’s takeover of Sun. Both the founder of Sun’s ZFS and the creator of Java have left the company now that Oracle is in charge. One has to assume that along with these two very public exits, there are many more employees following suit, or preparing to find other work as soon as possible. It’s pure speculation, but I believe that there is likely a clash of culture between Larry Ellison’s own-everything Oracle corporation, and the Sun that has over the years brought us technology like OpenSolaris and Java.

I’m the first to admit that I have absolutely no skill at computer graphics (or hand-drawn graphics, for that matter). Yet I find the need to do something in The GIMP at least once or twice a month, and if it’s anything beyond the basics it usually becomes a struggle to get the job done well. So if you’re anything like me, and your GIMP skills are in severe need of some improvement, you should check out these ten GIMP tutorials that teach some basic skills by having you do some quick and fun tasks.

Your life is becoming less and less private; what else is new? Along with social media exploits becoming more common, we now have to worry about viruses, malware, and spyware on our phones. Ars Technica is running a story that a large number of Android apps are invading your privacy. There will be more on this next week when the full report comes out; if you’ve got an Android phone, or any smart phone at all, you’ll want to keep an eye on this topic. Additionally, come back to TechThrob on Monday (or subscribe to the RSS feed or newsletter!) to check out my answer to a very common, very misunderstood question I’ve been getting about the effectiveness of secure deletion tools: just how effective are they on modern computers?

That’s all for now, but come back next week for some fresh, exciting items with a focus on privacy and Linux security! Have a great and safe weekend.

Softlinks, also called symlinks, are the easiest to understand, especially because you’ve probably already used them. A softlink fills the same role as a Windows shortcut. Simply put, a softlink is a file that points to another file. When you create a softlink, you are creating a new file that exists only as a pointer to a file elsewhere on the system.

All links are created with the ln command, using the -s flag if you want a softlink (if you don’t use -s, you’ll get a hardlink, which I’ll talk about in a second). The syntax of the command is:

For example, the following command will create a softlink to /usr/bin/firefox called firefox (in my “Desktop” directory):

You can see the softlink’s target by using the ls -l command. You can also use this command to detect broken softlinks:

Now that we understand softlinks, let’s talk about hardlinks.

Whereas a softlink is a new file that points to an already-existing file, a hardlink is another instance of the original file. A diagram is the easiest way to explain what that means:

You can click on either of the images for a larger version. What it explains is that, when you create a hardlink, you are creating another pointer to the data location on disk, not a pointer to the existing file. That means that editing a hard link of a file is equivalent to editing the original instance of the file.

To drive the point home: a softlink is a shortcut to an existing file, whereas a hardlink is a reference to a location on disk (or, more accurately, a location in the filesystem). This means that the concept of a shortcut, a link pointing to another file, doesn’t make sense for hardlinks. But, what does make sense is asking how many references exist to a given location on disk (how many hardlinks exist for a file), which you can see by running the ‘stat’ command:

So for example, in this screenshot I’ve created a file and then built three hardlinks to it. When I run the ‘stat’ command on any of the files, it will show that there is a reference count of 4:

There are two major limitations of hardlinks. In these cases, you must use a softlink:

1. A link across filesystems

Because a hardlink is a direct reference to the underlying filesystem, you can’t hardlink across filesystems.

2. Linking to a directory

You can’t use a hardlink to link to a directory.

In the cases listed above, you must use a softlink because a hardlink simply won’t work. There are also cases where softlinks are preferable to hardlinks, even though either will work. For example, you’d probably want to pick a softlink when you want to create a shortcut especially when the destination of that shortcut might change in the future. For example, if you have a launcher to a beta version of an application, you may wish to use a softlink so you can easily change the target of the link between versions.

In most of the remaining cases (creating a link to a file on the same filesystem), hardlinks can be preferable for the following major reasons:

1. Performance

There is a slight performance boost to be gained from using hardlinks. This is because since a hardlink references a spot on disk, rather than referencing another another file (which then references the actual spot on disk you want), there is one less disk seek involved in hardlinking.

2. Storage space

Hardlinks don’t take up any additional space, since they are simply a reference to an already existing space of disk. Creating a softlink is creating a new file, and will consume a small amount (usually 4KB) of space on your filesystem.

Additionally, hardlinks are preferable because a softlink is vulnerable to losing the ‘master’ instance of a file (the file to which all the softlinks point). If the original file is deleted, then all softlinks to it become invalid. With a hardlink, you can delete any of the instances, including the original, and as long as at least one instance exists the file will remain on the system.

Was this helpful?

I hope this information was helpful and easy to understand. If you have any questions or comments, either about this topic or other topics you’d like to see explained on TechThrob, please comment below!




]]> http://techthrob.com/2010/09/26/softlinks-vs-hardlinks-a-quick-explanation/feed/ 28 http://techthrob.com/2010/09/20/why-google-will-dominate-the-browser-wars/ http://techthrob.com/2010/09/20/why-google-will-dominate-the-browser-wars/#comments Tue, 21 Sep 2010 02:27:16 +0000 Jonathan DePrizio http://techthrob.com/?p=644 The browser wars are heating up again, with Mozilla, Google, and Microsoft as the main competitors. Google has announced its intentions to release several new versions in rapid succession, and Microsoft is pushing Internet Explorer 9. All the players realize that the stakes are higher than ever before, with more advertising dollars being poured onto the web, and with the boom of software as a cloud-based service. But ultimately, there is no question that Google is the strong favorite to win and for Chrome to become the dominant browser. Here’s why:
1. Chrome was built for Web 2.0

Google Chrome stands apart from all other browsers because of its speed – specifically its speed with JavaScript. From the start, Chrome was built as a minimal browser that featured a dedicated JavaScript engine which compiles JavaScript into machine code, which gave (and continues to give) it a huge performance advantage for web applications. Mozilla, on the other hand, was developed during the Web 1.0 era, and it shows; even though Firefox 3.0 features greatly improved JavaScript performance, it still can’t match Google Chrome’s snappyness. Google has a huge head-start on web application performance, and everyone else is playing catch-up.

2. Google knows how people use the web

Google has more information about people’s browsing habits than any other company, and therefore they have a huge advantage over the competition. Just where do they get all this information? Google Adsense and Google Analytics. Google analytics runs on a huge chunk of the top-500 websites, and all that information provides an invaluable insight into user’s behavior. It’s not far-fetched to imagine that Google Adsense can be used to gather the same data. (Adsense would be even more useful, since Google could track user’s behavior across websites.)

Google knows more about the average user’s screen resolution, color depth, machine performance, and usage patterns than anyone It’s impossible to overstate this advantage, and it’s one that must drive Microsoft mad with frustration. This knowledge provides Google with a direction of focusing its engineering resources, and allows them to pick up on new trends before anyone else.

3. Google provides a complete web package

When the desktop was king, Microsoft was without an equal; they made the operating system, the office suite, and the entertainment (remember Microsoft Flight Simulator, and all those other Microsoft games?). But as the pipe got wider and cloud-based applications grew in popularity, Microsoft was left in the dust and Google gained significant ground. Now, with Gmail, iGoogle, Google Apps, and YouTube, Google is positioned to provide a near-complete computing environment, all of it in the browser (hence the feasability of a Chrome OS, a direct threat to Microsoft on small formfactor devices).

Since it provides the services, Google has a unique opportunity for feature integration and interoperability when they provide the browser itself as well. If people use Google services already, and those services work even better in a Google browser, that’s a strong incentive to switch to Chrome; and since the user is already on a Google site, it’s free for Google to push an advertisement for their browser.

4. Users are getting smarter

There will always be Internet Explorer users, even after Microsoft stops making Internet Explorer. Some people simply don’t know, or care, about so-called ‘alternative browsers.’ These are primarily the moms & dads and the computer illiterate. But on the whole, users are getting smarter about these things; that’s simply something that is going to happen as technology invades more aspects of our lives and kids grow up with iPads and smartphones. People are also spending more time online, which means that their choice of web browser actually becomes increasingly important. When you combine these two points, you realize that the once insurmountable advantage of Internet Explorer — that it is installed on all Windows-based machines by default — is rapidly losing its importance.

The proof is in the numbers. If you have a look at the latest browser trends you’ll see that Chrome’s adoption is actually speeding up, whereas Microsoft is losing ground and Firefox has leveled out. I predict that by 2012, we’ll see a higher number of Chrome than Firefox users.

What do you think?

Which browser do you use? Which browser do you think is the best? Do you use Chrome, or do you think it’s garbage? Leave your opinions in the comment section below!




]]> http://techthrob.com/2010/09/20/why-google-will-dominate-the-browser-wars/feed/ 7 http://techthrob.com/2010/08/17/3-types-of-backup-you-need-for-complete-data-protection/ http://techthrob.com/2010/08/17/3-types-of-backup-you-need-for-complete-data-protection/#comments Tue, 17 Aug 2010 12:00:58 +0000 Jonathan DePrizio http://techthrob.com/?p=624 Note: This is a guest post contributed by StoragePipe.com.


When we think of data protection, most people just imagine themselves copying their computer over to another device on a regular basis… so that it can be copied back in an emergency. Of course, it’s not that simple.

There are many different challenges that make data protection difficult, and many different recovery scenarios need to be accounted-for:

• How would you react if you accidentally backed up a virus?
• What do you do if an employee accidentally deletes a file or saves over an important document?
• How fast can you get back up if your system goes down during business hours?
• What do you do if you have more data than you can reasonably back up?

These are just a few of the many data protection scenarios that you need to prepare for. In order properly defend yourself, you need a solution that is simple, modular and capable of handling a wide range of challenges.

The methodology I prefer involves 3 different backup processes which complement each other very well.



Disk Image

When you first set up your computer, you’ll want to install all of the applications you need and create a recovery image for this machine. This will come in handy if you ever need to perform a bare metal restore.

Restoring your system from a disk image, with all of your favourite applications pre-installed, can save you many hours when re-building your machine from scratch.

You’ll want to keep 2 copies of this system image. One copy should be kept on-site, and the other should be taken to a remote location for safety.

Regular Backups

Of course, when it comes time to recover, this disk image will already be several months old. Also, it will only contain applications…. not data.

What you truly care about the most is your irreplaceable data. All of those pictures, Word documents, and Photoshop files are very important and valuable to you. At the very least, you’ll want to back these up on a daily basis.

Also, you’ll want to maintain several historically versioned copies of all your data backups. This way, you can still recover your files if you accidentally back up a corrupted version. I recommend keeping about 30 days of historical backups… just to be safe.

And just like your system image, you should keep 2 copies of each backup… one off-site, and one close-at-hand.

Data Archiving

As you keep using your machine, you will accumulate a lot of junk that can quickly fill up your hard drive. Although you may not need any of this data right now, you might require access at a later date. This type of clutter can cause your backups to take much longer, and greatly extend recovery times.

In order to optimize your backup process and improve the performance of your machine, you’ll want to periodically clean up your hard drive and send inactive files off to an archival storage device. For this kind of long-term storage, I’d recommend a stable & crash-resistant media such as online storage or backup tape. (External hard drives have too many unstable moving parts)

A good policy is to archive any files that have not been accessed within the past 6 months. This should be enough to clear 60-80% of the space on your hard drive, and also improve backup & recovery times by 60-80%.

If you ever need these files again later on, retrieving them from the archives should be a simple matter.

3 Steps To Emergency Recovery

If your computer were ever to suddenly crash, you would first load up your system image to restore your machine and applications to their previous state, then you would load up your most recent backups. If you need any additional data that wasn’t included in the backups, you
can selectively grab only the files you need from the archives without having to load the rest.

Now you see how much easier backup and recovery can be when you’re organized. And with this approach, you’ll also be prepared for a number of other unexpected data loss scenarios.

About The Author: Storagepipe offers online backup services that are designed to simplify backups, and speed up recovery.




]]> http://techthrob.com/2010/08/17/3-types-of-backup-you-need-for-complete-data-protection/feed/ 0 http://techthrob.com/2010/08/10/public-service-announcement-verify-your-backups/ http://techthrob.com/2010/08/10/public-service-announcement-verify-your-backups/#comments Tue, 10 Aug 2010 12:21:53 +0000 Jonathan DePrizio http://techthrob.com/?p=599

There’s only one thing worse than having no backup at all: thinking you have a backup, and finding out it doesn’t work when you go to restore.

It seems like common sense, but unfortunately backup validation is often overlooked. After establishing a backup system, it’s vital that you periodically check to make sure that it is working and that you are able to restore in the case of a disaster. A system administrator that has configured a nightly backup but has never performed a test restore hasn’t done his job; he can’t say with any degree of certainty that he’ll be able to recover lost data in the event of a disaster, because he’s never tried.

There are many reasons why a backup might turn out to be a dud, even if you thought it was functional. Here’s a quick list, including things that I’ve either seen personally, or that I’ve heard about second-hand:

1. Your backup restores, but you don’t have a few vital files or directories it turns out you really need.
2. The backup used to work, but at some point the media became full, and backups haven’t been working for some time.
3. The backup used to work, but at some point the media became corrupted, and you can’t restore.
4. The backup target is a remote network host, and the SSH key changed. The backup script has been failing to login since then, and you don’t have any recent backups.
5. Your backups are working, but you aren’t backing up often enough to save everything you need in the event of a disaster.
6. The backup target is an NFS share, which at some point became unmounted, and you’ve just been making second copies of everything on the local hard disk — not very useful.

Notice that in all of these cases, the very first backup was completely successful, but over time something fell apart. Therefore, it’s not enough just to check your backup once; it’s vital that you periodically check to make sure everything is working and complete. While many of these cases can be handled by proper backup software (corrupt media, unmounted NFS share, etc…), others are things that require human intervention (such as making sure you’ve got all the files you need, and that you back them up on a proper schedule).

Additionally, when you periodically perform a restore test, you gain:

1. Confidence that the backups are good, and that they are dependable in the event that you should need them.

Peace of mind is priceless.

2. A tested backup procedure.

Having a data-loss event on your hands and having to restore without a procedure to follow is nerve-racking. If you’re in charge of restoring data for a company, you should have a written procedure to follow. This way, not only will you know exactly what needs to be done, but it will be possible for others to restore in the event of an emergency. The procedure should be written in such a way that someone familiar with the backup system can follow it to restore the vital data if necessary.

So if you haven’t already, go now and make sure that your backups can be restored, and that you have everything you need.

What’s your backup system? Do you periodically make sure that your backups are functional, and you’re backing up everything you need to have in the event of a disaster? Are you sure that your are safe in the event of system loss? Share your backup and restore method in the comments below.

Absolutely brilliant photo credit goes to Matalyn.




]]> http://techthrob.com/2010/08/10/public-service-announcement-verify-your-backups/feed/ 0 http://techthrob.com/2010/08/04/get-a-dynamic-interplanetary-background-with-xplanet/ http://techthrob.com/2010/08/04/get-a-dynamic-interplanetary-background-with-xplanet/#comments Thu, 05 Aug 2010 03:00:30 +0000 Jonathan DePrizio http://techthrob.com/?p=518 This tutorial will show you how to setup a cool, dynamic wallpaper for your computer based upon XPlanet. The image to left is the final result of this how-to; notice the cloud map and the daylight, which are both periodically updated to match real-time cloud data and sunlight. You can chose to do the same thing with your background, or to customize the settings to your individual taste. This article will show you how to configure xplanet to be your desktop background in Gnome, so it will work in either Ubuntu or Fedora. With a little tweaking to this desktop modification, you should be able to get it to work under most environments and distributions.
1. Installing xplanet

The first thing you’ll need to do is install xplanet. This can be done quickly and easily from the command line:

Ubuntu: sudo apt-get install xplanet
Fedora: sudo yum install xplanet

2. Running from the command line

Xplanet has lots of options, which you can see in its man page if you run ‘man xplanet’. I did find that the manual isn’t entirely up to date, however – it doesn’t list all the map types that xplanet actually supports with the -projections flag. Nevertheless, the manual is still a good place to start if you’re looking to explore xplanet’s featureset.

You can run xplanet from the command line to get an idea of what kind of map you want to generate, how large it should be, and what options you want to use. For example, you’ll probably want to generate an image that fits your screen resolution. Use the -geometry option to specify the size you want, in pixels. You can use the -window option while you experiment, until you get the map exactly how you want it:

xplanet -projection rectangular -geometry 1360×768 -window

The above are the options that I use, but of course you should play with it until you find something you like. One thing you’ll probably want to tweak is the -projection option, which determines what kind of map you want to generate. Also check out the -latitude and -longitude options to tell xplanet where to center the map; you can set it so your location is at the center of the image, if you want. Check out the man page for all the details (there are many!). To help get you started, here are a couple of fun projections and the commands to generate them:

A zoomed-out globe with New York at its center:



xplanet -radius 30 -num_times 1 -latitude 40 -longitude -73 -projection orthographic

You can view more than just the Earth; here’s a spectacular view of Saturn!


xplanet -body saturn -latitude 25
3. Setting the background

Once you’ve picked out the options you want to use for your background, you need to tell xplanet to save it to a file so you can select it as your wallpaper. Simply use the -output and the -num_times 1 options on the command line and xplanet will run, save the generated image to the file specified by -output, and exit. Be sure to set the -num_times 1 option, or xplanet won’t close after generating the image.

Next, you’ll want to set your wallpaper to be the saved image. Do this just like you would normally set your wallpaper; you can go to the System menu in either Ubuntu or Fedora, and under Preferences select Appearance.



Or, you can right-click on the desktop and select Change Desktop Background. Either way, click the “Add” button and add the image you saved with Xplanet. Now that will be your background.

But, there’s more to do!

4. Getting the clouds

One of the coolest features of xplanet is that it has the ability to overlay a “cloud map” showing the current cloud coverage on Earth. If you’ll notice in the screenshot at the beginning of this article, my desktop includes a cloud map overlay. There are two choices for setting up the cloud map:

• Download a static cloud map

If you don’t care about having the cloud coverage update itself periodically, you can download a single image and use it whenever xplanet renders the Earth. Simply save this file somewhere, and proceed to the next section about “Creating the configuration.” Or, for more fun…

• Periodically download an updated cloud map automatically

The other option is to setup a script to periodically download an updated cloud map, so that your wallpaper matches the current cloud coverage of the planet. It’s a little tweak, but it’s definitely fun. If you decide it’s worth the effort, here’s what you need to do:

1. Setup the script to download the cloudmap automatically

Download this script and decompress it. This script was written by Michal Pasternak and is in the public domain. It is useful because it checks if a new cloud map is available before actually downloading it, which saves a lot of bandwidth.

2. Run the script once to generate the cloudmap

Once you’ve downloaded the script, make it executable by running the following command in its directory:

chmod +x download_clouds.py

Next, run the script so it will download the initial cloud map:

./download_clouds.py

By default, the script saves the map with a filename of clouds_2048.jpg.

Now continue to the next section, which will show you how to setup the configuration file in order to use the cloud map. Keep reading to the “putting it all together” section to create an automated cron job so the cloud map will update itself periodically.

5. Creating the configuration

If you’re satisfied with the image you generated previously, that’s fine; you can skip this step. But if you want to add clouds or lights, you’ll need to modify the xplanet configuration file to let it know where to find these added goodies. It’s done in a text editor, but it’s pretty simple.

The easiest way to proceed is to modify the default configuration file, by opening it in either vim or your favorite graphical text editor. On both Ubuntu and Fedora, the default configuration file is located at /usr/share/xplanet/config/default. You’ll need to be root to edit it (optionally, you can copy it to your home directory and then edit it, if you don’t want to make system-wide changes).

Inside /usr/share/xplanet/config/default, search for the line [earth], which specifies the options to use when drawing a picture of Earth. Here’s my [earth] section of the configuration file:

[earth]
“Earth”
color={28, 82, 110}
cloud_map=/home/jdeprizi/bin/xplanet/clouds.jpg
night_map=/home/jdeprizi/bin/xplanet/night_xplanet1.jpg
#marker_file=earth
min_radius_for_label=0
#satellite_file=iss

While you should certainly check out what happens if you uncomment satellite_file or marker_file, the two things I want to mention are cloud_map and night_map. The cloud_map option should be set to the image you specified in the section above, “Getting the clouds.” This tells xplanet to overlay the cloud map onto the generated image, and yields a result similar to the screenshot at the beginning of this page.

When you specify the night_map option, xplanet will draw city lights in the part of the Earth where there is no sunlight, like so:



Your night map should be located in /usr/share/xplanet/images with a file name night.jpg. In the above example, I copied it into my home directory.

6. Putting it all together – cronjob and login trigger

Now that you have your background looking just the way you want, you’ll need to configure a scheduled job to make sure that it updates the daylight and the cloudmap automatically. The easiest way to do this is by scheduling a job using cron and gnome-schedule. Use the command you came up with above, and schedule a job to run as often as you want — I generate a new image every 30 minutes. I also download the cloud map every 12 hours:



You’ll also need to have the map generate when you login, especially if your computer is off for long periods of time. If you don’t do this, the map won’t regenerate until the next cronjob kicks off, and you could be looking at a very outdated image for up to an hour. To have the wallpaper refresh when you first login, simply go to the Startup Applications item under System and then Preferences. Add a new item with the same command as you used above, to generate your background:



Now your wallpaper will automatically refresh whenever you login.

7. Now let everyone see!

If you’ve followed through to this point, you should have a fully-functional xplanet wallpaper that will automatically refresh itself, following the interval you specified. Awesome! Show off your work by posting a screenshot to the TechThrob Facebook gallery. Also, leave a comment with the options you use to generate your background, so others can see what kind of cool tweaks you’re using!




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