As storage requirements continue to grow, external storage is becoming increasingly popular.  While the simplest way to deal with this growing demand is to attach an external hard drive via USB, many users demand more power and flexibility; for example, the ability to provide storage over a network, or divide storage for various uses. For this, SAN, or Storage Area Network, is the most powerful tool available, and iSCSI is a free and common way to create a SAN.

This article will discuss how to create a simple Storage Area Network with a file server presenting storage to another machine.

Some SCSI Terminology

If you are already familiar with SCSI, you can skip this section. Otherwise, give it a read before you continue. I will be using these terms extensively throughout the rest of the article.

Target -  Your iSCSI Target server is the server that physically has the storage, and is presenting it over the network to the initiator.  Essentially, your fileserver is your target.

Initiator -  The initiator is the machine on which the target’s storage will be mounted and used, over the network.  This is your HTPC, your workstation, laptop, etc..

LUN – I will be calling any unit of storage shared over iSCSI a LUN. LUN actually stands for Logical Unit Number, or the number assigned to this unit of storage. It is a logical unit (as opposed to a physical unit), so an entire RAID array, a single partition, even a file, can become a LUN and used for storage.

Setting up the Target

The first step is to setup your storage server with the necessary software.  You’ll have to install the iscsitarget daemon, which can be installed on Ubuntu/Debian systems with the command:

Once that’s installed, it’s necessary to do some configuration in the /etc/ietd.conf file to specify what you want to share over the network.  You can share a block device (e.g, a hard disk, a partition), a RAID array, an LVM device, or even a file (this file  can be an ISO of a DVD, or just some empty file you’ve created to act as an independant storage device.  I’ll talk more about this later).  Here, I will be sharing a Linux MD device (a software RAID device) as well as a 50GB file.

Configuring /etc/ietd.conf

The ietd.conf file usually comes with some examples, but they’re confusing and not all that helpful.  It’s easier to just write your iSCSI target lines at the bottom, by hand.  The /etc/ietd.conf file is only readable and editable by root, so open it with your favorite text editor, for example “gedit”, like so:

For my setup, sharing a single MD device and a single file, I added the following lines to my configuration file:

Target iqn.2009-01.voyager:storage.homeShare
Lun 0 Path=/dev/md0,Type=blockio
Lun 1 Path=/root/fiftyGBFile,Type=fileio

That’s all that I needed to configure in this file.  Obviously yours will be different; here is what the lines mean:

Target iqn.2009-01.voyager:storage.homeShare

This defines an iSCSI target, as discussed above in the terminology section.  The “iqn…” part is the target’s name, which must be unique.  The name takes the format:

iqn.YYYY-MM.[domainname]:[unique identifier]

YYYY-MM is the year and month that the target becomes valid, so it is the current year and month.

The domain name is the name of the machine on the network; if you are sharing over the internet, you will want to use your actual domain name (in reverse order, so com.example instead of example.com).  If you are just sharing over your home network, you only need to specify your hostname.

Finally, specify a unique identifier for this target.  I used “storage.homeShare”, because this is the share for my home.  You may chose something more descriptive, such as “mediaTarget” or “remote.backupServer”.

The next two lines specify which LUNs are shared through this target, starting with 0.  You must define a path and a type.

Lun 0 Path=/dev/md0,Type=blockio

In this example I am specifying /dev/md0 which is a 2TB software RAID volume, and /root/fifty50GBFile, which is a blank file I created using the command:

Of course, for files you could have chosen (for example) an ISO or IMG file, to be mounted by the iSCSI initiator as-is. In this case, I created a blank file because I plan to write a filesystem to it and use it as a backup device. Then, this file will contain an ext3 filesystem which can be mounted by any computer to access my backups, as opposed to having a physical disk for backup.

The Type= line determines how iSCSI will treat writing to the device.  In my case, I want to treat my RAID device using blockio, but the file I created using fileio.  If in doubt, use fileio, or read more about these two options in the manual for iscsi.

Once you have finished editing your ietd.conf file, save it and restart the iscsitarget daemon, for the changes to load:

Now you are ready to move on to the initiator, who will receive the storage from the target.

Setting up the Initiator

The first thing to do is install the initiator software, which is the open-iscsi package.  In Debian/Ubuntu Linux, this can be done with the command:

Next, you will need to make sure it is started:

Now, you need the initiator software to “discover” any iSCSI devices being shared by your storage server.  To do this, simply run:

If everything is setup correctly, the iscsi_discovery tool will report back that it has found a target.  For example:

jdeprizi@enterprise:~$ sudo iscsi_discovery -d 192.168.0.6
Set target iqn.2009-01.voyager:storage.homeShare to automatic login over iser to portal 192.168.0.6:3260
discovered 1 targets at 192.168.0.6, connected to 1


To verify that it worked correctly, you can run the command:

If all has gone as planned, you will see one “VIRTUAL DISK” for each LUN you created. To see where these devices have shown up on your system, use the command:

In my case, I have created two LUNs; so I see two “VIRTUAL DISKS” of LUN 0 and LUN 1:

Host: scsi3 Channel: 00 Id: 00 Lun: 00
  Vendor: IET      Model: VIRTUAL-DISK     Rev: 0
  Type:   Direct-Access                    ANSI  SCSI revision: 04
Host: scsi3 Channel: 00 Id: 00 Lun: 01
  Vendor: IET      Model: VIRTUAL-DISK     Rev: 0
  Type:   Direct-Access                    ANSI  SCSI revision: 04

And when I view /proc/partitions, I see my devices at sdc and sdd:
8 32 1953524992 sdc
8 48 52428800 sdd

Controlling the devices

Finally, you are ready to use your iSCSI shared devices.  You can treat them like you would a normal disk attached to your system, which is the real power of this technology.  You can create a filesystem on them, even partition them into smaller pieces, as you would a physical hard drive.

This is mostly outside the scope of this article, but for a quick demonstration, if I were to format the 50GB LUN (sdd on my initiator) as ext3 and mount it, I could do:

Conclusion

Using iSCSI technology to create a simple Storage Area Network isn’t the easiest task imaginable, but it really isn’t too hard, especially for a basic home setup. Sharing the devices over gigabit ethernet means file transfers are fast enough that you can use your network shares as if they are local, and, with iSCSI/SAN, you can treat them that way, too: creating partitions, writing individual file systems, and mounting them as their own devices.

References

The most useful documents, and also the most immediately available, are of course the man pages:

man ietd.conf
man isciadm

BTGuard is a paid proxy service intended for bittorrent users. For $6.95 a month you can use BTGuard to hide your IP address from other downloaders and bypass any traffic shaping your ISP performs to limit your bittorrent usage. I’ve given this service a try, with mixed results. Read on for more.

BTGuard provides a Socks5 proxy, through which you pass your bittorrent (or other data) traffic before it goes out to other members of a bittorrent swarm. As a result, the tracker, as well as anyone else on that torrent, will see the BTGuard IP address rather than your own; your identity effectively stays hidden from the public.

When you register for a BTGuard account, you set a username and password, which you use to identify yourself to the proxy. This is called Socks5/A, or Socks5 with Authentication. Consequently, the service will only work with programs that support this proxy scheme; most bittorrent clients do, with the notable exception of Transmission (now the default client for Ubuntu Linux).

It is possible to use the proxy for more than just bittorrent traffic; but as of yet I have been unable to find a web browser with Socks5/A support. This includes Firefox, Opera, Konqueror, and Internet Explorer. However, any program that has support for this protocol should work, and the primary intention of the BTGuard service is for bittorrent anonymization.

In my tests, I used various clients, including Deluge, Azureus, and uTorrent (running via Wine).

Setup
Setting up your client to use BTGuard (after you have procured an account) is simple, and instructions are provided on the BTGuard website for the most popular clients. The only information you have to fill in the proxy address and port number, as well as your username and password. Once you configure your client to use the proxy, you’re good to go.

Speed and reliability
Unfortunately, the speed of the BTGuard service isn’t quite up to par. While my download cap from my ISP is quite high (I’ve often hit 2MB/s, sustained), when routed through BTGuard this falls to approximately 100KBps on average, with peaks around 300KBps and lows of 50KBps. These speeds are sure to disappoint serious downloaders with fast connections, but for someone who only occasionally grabs a file or two it may be acceptable.

Another problem with BTGuard is reliability; more than once I noticed my connection dropping entirely for short periods (about 30 seconds) before it would start up again. I ran all tests with several Linux ISO files downloading at once, so I can say with certainty that the strength of the bittorrent swarm was not the issue; this is also a problem I only encounter when using the BTGuard proxy service.

Overall, using BTGuard will most likely mean a slower, less reliable connection (at least for now, or until they upgrade their systems to meet with demand), and it’s something to consider before spending $7/month on the service.

One of the largest questions about BTGuard is simple: Can you trust them? When you use a proxy, you’re sending all your data through someone else’s servers; as a result, they can view and log everything you do. Unfortunately, there isn’t any readily-available information on exactly who is behind BTGuard. On their website they explicitly state that they do not keep any logs, but you have to take them at their word.

Using BTGuard to become anonymous changes your bittorrent security paradigm from “security through obscurity,” or becoming lost in the crowd, to “security through trust” of BTGuard’s systems. It’s up to the individual to decide whether or not they want to trust BTGuard.

Speed

The number one thing BTGuard needs to do to improve their service is make it faster; 100KBps on average is simply too slow for bittorrent traffic. As more users sign up for the service, their “tubes” will become increasingly full, and individuals will see their download speed decrease; hopefully BTGuard will vigorously combat these growing pains and provide a faster service.

Security
BTGuard needs to make it clearer that you can trust their service. More legal information, more information about who exactly is running the service, and a better privacy policy are must-haves before many people will consider them trustworthy.

Pricing
Currently, the BTGuard service costs $6,95 a month, which I think is fair for what they provide (although speed remains an issue, and some people will likely be turned away from paying for a service as slow as it is now). However, there is no long-term pricing; you can sign up for one month, or a recurring monthly payment, but there is no price difference. A 12-month discount price, for example, would be a nice addition; perhaps $75 instead of the current $83.50.

BTGuard fills an important niche, and many bittorrent users will likely be willing to pay for such a service, but it’s currently plagued by some significant problems that will turn many potential users. If the company is able to increase available bandwidth, deal with its growing pains, and make themselves more trustworthy, it’s likely that BTGuard will become a powerful tool in the fight for privacy on the internet.

Know the laws in your country and locality. I do not suggest, condone, or practice the violation of national or international copyright law. The BTGuard service explicitly forbids using the proxy to commit illegal activities, including copyright infringement. No laws were broken or copyrights infringed during the writing of this article or review of this service.

Preload is an “adaptive readahead daemon” that runs in the background of your system, and observes what programs you use most often, caching them in order to speed up application load time. By using Preload, you can put unused RAM to good work, and improve the overall performance of your desktop system.

Installing Preload on Ubuntu is easily done with the command:

Preload is in the package repositories of many different managers, so users of other distributions should check their appropriate package managers to see if it’s available. If not, you can always install Preload via its page on SourceForge.net



Once installed, Preload will start, and no further action is necessary, but read on for configuration options, to learn how to monitor Preload’s activities, and see what kind of improvements Preload will bring to your system.

The configuration file for Preload is kept in /etc/preload.conf and the default values should be fine for most people. But if you want to tweak the operation of Preload, an explanation of the options is available in the configuration file as well as in the paper written by its developer, Behdad Esfahbod.
Some common options available are:

As I noted previously, the default values should be fine for most people, and you really shouldn’t change these values unless you have a specific purpose in mind.

I’ve heard concerns about Preload’s RAM usage, so I want to make it clear that Preload will not drain your system memory! On my system with 1GB of RAM, preload has given itself 83670kb as it’s maximum available memory size; and of that, it’s only using 35% of that at the moment!

If you want to check up on what resources Preload is using, you can monitor its logfile by running:

By default (you can manually set the verbosity of Preload with the “-V” flag; for more information, check Preload’s man page) this won’t tell you much information about Preload except for the amount of memory it has allocated and how many files it’s watching. If you want more information about the specific files that Preload is caching for you, look at this file:

The beautiful thing about Preload, however, is that you can ignore these files completely; you might want to check up on the log every once and a while, just to make sure that it’s running, but Preload will happily sit in the background and stay out of your way.

It’ll take a little while before Preload starts to understand your usage patterns, so don’t expect to see a drastic change in performance right away. Also, if you’re just opening/closing applications repetitively, your computer will store those files in cache anyway (this is called a “warm” load), so you won’t see any difference in speed there. You will, however, see a speed improvement if, for example, you use a program intermittently; these programs will startup faster than without Preload.

The author of Preload, Behdad Esfahbod, has written a paper in which he provides some sample figures for the speed effects of Preload:

Or, for those that prefer graphs to tables:

Keep in mind these numbers are not representitive of current hardware. Modern machines will probably beat the raw timing of these numbers in even cold-start times, but obviously will still see an improvement in speed with Preload (I wasn’t able to find any modern benchmarks to compare, but I imagine they will be similar in terms of percent of speed improvement). For more information, read the developer’s thesis paper.

As you can see, larger applications benefit more from Preload, although all applications do benefit at least a little bit. Since Preload is configured to start during bootup, even the amount of time it takes to login to a complete desktop is enhanced by Preload. Keep in mind these numbers were generated several years ago! Modern machines will probably beat these numbers in even cold-start times, but obviously will still see an improvement in speed with Preload! For more information, read the developer’s thesis paper.

Preload can provide a great improvement in application startup time; since most modern machines have a good deal of memory to spare, Preload puts this RAM to good use. I highly recommend installing Preload on your desktop machine, and although it may take a little while for the daemon to learn your habits before your see any real performance improvement, it’s a great tool that increases the speed of your system while staying in the background, out of your way.

There has been a lot of debate recently over whether or not it’s a good idea to run an anti-virus program if you’re using Linux. Reading the forums, I see a lot of misunderstandings, particularly around what exactly it is that these anti-virus programs do and whether or not they’re necessary. I hope to clear up some of the confusion regarding the anti-virus situation on Linux.

When you think of an anti-virus program, especially if you’re coming from a Windows world, you think of a program that runs in the background and scans files as they are accessed (or, perhaps you have your entire system scanned on a regular basis) to see if anything is infected with a virus. This is an effective way of detecting and removing viruses on a desktop computer; and for a Windows machine, it’s all but a necessity given the vast amount of threats circulating on the Internet.

Linux anti-virus programs don’t work this way, because Linux anti-virus programs aren’t meant to protect the desktop machine from Linux viruses. An anti-virus program running on Linux is designed to detect Windows viruses, so that they aren’t spread, unknowingly, by the Linux user.

If you’re running Linux, you are, in a practicality, immune from a Windows virus. So why would you want to bother scanning your files – files that won’t work on your computer, anyway (except, for example, through Wine) – for viruses that have no effect on you? Well, the simple answer is, you wouldn’t. But it is more complex than that. I’ll explain.

Mail servers
The vast majority of Linux anti-virus programs run on mail servers. These are the computers that your mail client connects to when you want to send or receive an email. Since email is one of the main way viruses and trojan horses spread, these servers are the “front-line” in the battle to stop computer viruses. And, since so many of these servers run Linux, it’s clear to see the need for a Linux program to detect Windows viruses. If you’re running a mail server, whether it be for your home or office, you should definitely be using an anti-virus program to intercept any naughty files that might be trying to move in or out of your network via email.

File servers
Another place where you’d want to run an anti-virus program is on a file server shared my multiple users, even if you trust all of these users. File servers are basically repositories for data; some of that data might come to exist on your server through legitimate sources, but there’s no way for you to know where each and every file originated. Running an anti-virus ensures that if someone uploads an infected file, say, downloaded from a Peer-to-Peer network, your file server will detect the threat and stop any other users from becoming infected.

Now that you understand what exactly these anti-virus programs for Linux do, it’s up to you to decide whether or not you want to implement them if you’re just running a standard Linux desktop machine. If you have Windows computers on your network, and you’re sharing files, it’s probably a good idea to run something like ClamAV, to keep those other machines safe.

Let me explain how I use my Linux Anti-Virus program on my desktop. I use ClamAV, but I don’t keep it running in the background (this uses up resources, and since I’m not running a mail server or transferring lots of files, it really isn’t necessary). I only use it from the command line when there is a specific file of questionable legitimacy I want to test; this is a great service I can provide to Windows-using friends. Since I’m immune to these viruses, I can check out files before they download them.

I hope I’ve cleared up some of the confusing around Linux anti-virus programs, and that I’ve answered the oft-repeated question, “Do I need to run an Anti-Virus on Linux?” In reality, the type of setup you have, and the quantity of your paranoia dictate the answer to this question; but for most people, it simply isn’t necessary to run an anti-virus in Linux.

Griffith is an application for the Gnome desktop that organizes your movie collection, much in the same way Alexandria is used to organize your book library. Simply by entering the name of a movie, Griffith will query various databases on the internet and download cover art, plot details, and cast information.

Griffith is probably included in your package management repositories; for Ubuntu, you can install it by running:

But you can find more information about installation, including a Windows version, at the Griffith download page.

The nicest part about using Griffith to organize your movie collection is that it does all the work for you. By clicking on the “add movie” button, you’ll see a window for a new entry:

You can see here that I’ve entered the title of a movie, and on the right side there is an option to select the database which Griffith will query for the movie’s information. Griffith supports over 25(!) different databases on the Internet, but the International Movie Database seems to do a great job at providing all the information needed for a movie.

Once you click “Get from Web,” Griffith will go out and find the details for your movie. Most likely, it will return a list of movie titles that are similar to the one you entered, and ask you to select the correct movie. Normally this will be the first movie listed, but if, for example, there were several remakes of a title (“Hamlet” would be a good example), it also lists the year in which the movie was produced, letting you select the appropriate item. Once you tell Griffith which movie you want, it will fill in all the information for you, automatically:

You can repeat this process for part or all of your movie collection; when you’re finished, you’ll have a Griffith window filled with your movies. You can select the movie you want to view, and tab between all the information downloaded by the program. Griffith will even let you grab a larger version of the cover image from Amazon.com, and then help you print it out.

Adding personalized information
Now that you’ve gone through the hassle of adding your movie collection to Griffith, and you’ve had all the information about your titles entered automatically by the program, you can start manipulating your collection to suit your needs. For example, you might choose to rate movies, which Griffith allows you to do on a scale of 1 to 10. The little thermometer icon will indicate how well you’ve rated a movie. You can also tell Griffith about the media on which a movie is stored; is it a DVD? What region encoding does it use, and what quality is the disk in?

Search
Searching through your movies is easy, and you can filter by pretty much any type of information Griffith stores: from title, to genre, to director, to year. You can also indicate whether you’ve loaned out a particular movie, and to whom; so you’ll never wind up arguing with a friend again over whether or not she still has your copy of Back to the Future.

Exporting your database
What fun is cataloging all your movies, if you can’t show off your massive collection to your friends? Griffith’s export function is simply amazing. Not only does it let you export to PDF, HTML, XML, CSV, or iPod formats, but it lets you fine-tune exactly what data you want to include. Personally, I would want to use the HTML export function the most, and when I selected this option I was amazed at the control Griffith gives you over the output:

Not only can you select various themes for your HTML movie list, but you can choose which information to include, and what you want to leave out. You can also set how you want Griffith to split the entries, how titles should be sorted, and which movies you want to leave out altogether.

Movie buffs as well as casual collectors will love Griffith’s ability to generate an entire, well-documented database simply from knowing the title of a movie, and the single push of a button.

Google’s Picasa software is a powerful tool for managing your photo collection. It provides a simple interface for organizing your pictures, as well as some easy-to-use, yet powerful image manipulation tools. However, until recently the Windows version of Picasa has had some features that put it above the Linux version; some of these features, like Picasa Web Album integration, are at the core of the program, without which Picasa isn’t very useful. With its newest release, the Linux version is being brought up to par with its Windows counterpart.

Picasa 2.7 is still in beta, so it isn’t included in many repositories just yet. However, Google provides easy-to-install packages in RPM and DEB formats on their download site.

The major new feature in Picasa 2.7 is integration with Picasa Web Albums, but we’ll get to that later; there are a plethora of other upgrades that make this new version worth getting excited about.



Save/revert edits
Picasa has some great image manipulation features. You can apply basic filters, as well as fine-tune an image based on fill lighting, highlights, shadows, and color temperature. There are also several effects you can use, such as sharpening, tinting, saturation, and others.

Picasa now allows you to save these edits either to the original file, or to create a new image with the modifications. More importantly, however, is the “revert” option, if you decide the original was better than the modified version.

View images by folders
One of my favorite features is the ability to find and sort files by their location in the filesystem, rather than sorting by albums in a library. This allows you to use your existing filing method to sort your pictures, rather than forcing you to create an entirely new system to use Picasa. A small change, but a very useful one nonetheless.

Better camera importing
Along with the ability to use your existing folder structure for picture imports, Picasa now allows you to import images from your digital camera using this filesystem structure. Google has also added better RAW support; you can read more about these features on Google’s website.

And now the feature we’ve all been waiting for – web album integration – is finally here! And I have to say that the implementation is as straight-forward and simple as it could possibly be.

Once you’ve logged into your Picasa Web Albums account, you’ll see your account information in the upper right corner of the screen:

Now, you’ll be able to create web albums, upload images, and manage existing albums via the Picasa desktop interface. Right-clicking on an image gives a contextual menu that will allow you to upload the image to your web gallery:

Clicking this item will open the Web Album manager, which lets you choose the option of adding the image to an existing album, or to create a new album.

All in all, the new interface for managing, uploading, and modifying Picasa Web Albums is a great improvement, and one that has been sorely lacking in the Linux version of Picasa for some time. With this new feature, Picasa for Linux becomes, in my opinion, the easiest to use photo management and web gallery software available for linux.

There are quite a few imaging programs for Linux. FSpot and Gphoto are two that come immediately to mind; and while they’re good programs, I have to say that Picasa has really began to mature, and is starting to impress me as a possible complete replacement for these other image cataloging programs. Of course, unlike its alternatives, Picasa is a closed-source application (not to mention, it runs via Wine on Linux), so there are several licensing as well as philosophical issues to be dealt with before Picasa becomes the default image manager for any Linux distribution.

If you’re thinking about trying out this new version of Picasa on your production machine, it’s not a decision you should take lightly. There are quite a few known bugs listed on the Google Picasa for Linux page, and even though most of them fall into the “vaguely annoying” catagory, it’s probably best to wait until the official release until you upgrade. If you just have to have the latest version – and you’re especially excited about the web album integration – I don’t think it’d be too harmful to try out this beta. Just remember that there will be bugs!

While it may not let you go where no man has gone before, Celestia is an amazing desktop application that lets you travel anywhere in the known Universe.

You can view any object in the Solar System, travel to distant stars, and even leave the Galaxy to view planets only recently discovered by NASA and global space agencies.

Celestia is cross-platform, which means you can run it on Windows, Mac OS X, or Linux. It’s also open source, so if you’re using a different operating system, or if it’s not available as a binary package for your distribution, you can compile it yourself.

Windows and Macintosh users should head to the Celestia download page, while Linux users should check and see if it’s available through their package manager. In Ubuntu, you can download Celestia using the following command:

By default, Celestia uses a QT interface, which will work great in a KDE setup (such as Kubuntu). Gnome users will probably want to install the Gnome front-end, using the command:

There are also loads of add-on packages available for Celestia, which increases the size of the database of objects Celestia is able to view. These include various spacecraft and satellites, deep space objects, and even fictional objects such as space bases in Star Trek and Babylon 5. For a complete list of add-ons, check out the Celestia Motherlode site.

Once installed, you’re ready to start navigating your way around space in Celestia. The first thing you’ll probably want to do is check out Earth, or maybe some of the other planets in our Solar System. By default, Celestia comes with the graphics for objects in the Milky Way, such as each planet’s moons, various asteroids, stars, and comets. The Gnome front-end has a really handy tour guide feature, which will let you select some of the more popular attractions in space:

Selecting “Go To” will take you on a journey through the millions of miles to whichever object you have selected. I traveled to the comet Borrelly, and was able to view this beautiful image taken by the Deep Space 1 spacecraft:

Next, I was curious about how things looked from the most distant parts of our Solar System, so I traveled over to the ex-planet Pluto, to check out how things looked from that icy rock way out in space. Celestia gave me a beautiful view of Pluto’s moon, Charon, which you can see in the upper-left corner here, and you can see all the inner planets labeled in the distance:

To travel back, I simply right-clicked on Saturn and selected “Go-To”; stars in the background whizzed by as Jupiter and one of its moons, Titan, approached, giving me this wonderful view:

I could have spent hours traveling around the planets and asteroids in our Solar System, but I wanted to get into Outer Space and see what else Celestia could do.

Celestia comes with a very handy Star System Browser, which will show you a list of known stars, and you can sort by distance, known planetary systems, or brightness. Personally, I find stars with planets to be the most interesting, since they’re the ones that will likely have life, so I selected the Wolf 562 system. Once Celestia traveled to this distant star, I was able to see its planetary companion (romantically named “b”), and plot its orbit around its mother star.

Obviously, there are hundreds, if not thousands, of other stars objects to explore. That’s the fun of Celestia! You’ll never run out of objects to view, or new things to find. And for more cool pictures, check out the Celestia Screenshot Gallery!

I heard on the news that there will be a lunar eclipse today (Feburary 21, 2008). Unfortunately, I’m not in a position to see it; but with Celestia, I can get a 3D simulation of any eclipse (Solar or Lunar) and of any planet, at any point in history – or even the future! Celestia’s eclipse finder lets you enter a date range, and select which eclipse you’d like to view:

Even though I won’t be able to see the Lunar eclipse today, I can still check out the view of the Earth, Sun, and the Moon lined up, using Celestia:

I haven’t really discussed the details about what type of information Celestia shows you. Obviously, you can set it to label stars, orbits, planets, and other bodies; it will tell you the surface temperature and luminosity of any object, its distance from any other object, and what class planet or star something is. This is all really great information for astronomers, and I have no doubt that this software will serve as a useful tool for anyone in that profession or field of study. But Celestia is great even for those who are just interested in space and the Universe. Celestia lets travel millions of light years without ever leaving home!

One of the great things about using open source software is the frequency with which bugs are fixed, security holes are patched, and new features are added. Ubuntu includes a very convenient update manager, which checks the software repositories for updates, and alerts you to install any new versions found. However, its default behavior of checking for updates every day annoys some people. Sometimes updates will be released multiple days in a row, and constantly upgrading your system. can start to be a burden. This guide will explain howto control how often the update manager runs, or howto set the update manager in Ubuntu to automatically install updates.

The update manager is controlled through the Software Sources control panel. Under your “System” menu, select “Administration”, and select “Software Sources.” You will be prompted for your root password; once the window opens, select the “Updates” tab:

The section we’re concerned with is the bottom half, “Automatic Updates.” You should, however, probably make sure that all the update sources are checked.

First, you can disable automatic updates entirely by unclicking “Check for updates.” I don’t recommend this, as updates are important to keep your stable and secure; so unless you’re planning on updating your system manually, leave automatic updates turned on. You can select how often you’d like the update manager to check for updates via the drop-down menu; you can select “Daily,” “Every two days,” “Weekly,” or “Every two weeks.” This setting is really just a personal preference.

The options below the update frequency menu are pretty self explanatory. You can have the manager install updates automatically, without asking you; if you set it to do this, it will still prompt you before your computer reboots in the event that the machine has to restart for an update to take affect (unlike Windows, which requires restarts for lots of updates, Linux typically only requires a restart if the kernel is updated).

The other options are to download updates in the background, which will prompt you to install them at a later date, or to just tell you when there are updates available, in which case the update manager will download packages when you manually update your system.

Updates are an important part of keeping your system stable and secure. But sometimes they can be annoying, when updates are released almost every single day. Thankfully, the update manager allows you to configure often you want Ubuntu to update itself, or it allows you to make the process entirely transparent (by automatically installing updates).

With Linux becoming more popular and easier to use, more and more people are adopting it as their primary operating system. But the transformation from Windows user to Linux user can be a tough road to take. Most new users become long-term users because they have friends that introduce Linux to them, and help them through the first few weeks of rough-patches. Here are ten steps to help you introduce Linux to a would-be convert.

Let’s face it – Linux isn’t for everyone. Your grandmas, your uber-gamers, your technophobes; all of these are bad candidates for Linux conversion. You want someone that’s interested in computing, and someone that is decently tech-literate. The ideal candidate is one that has heard of Linux, but for whatever reason believes it would be too complex for him or her to use. Another important quality in a mark is someone who’s willing to take some time and work through the initial phase of changing to a new operating system. If a candidate doesn’t have these qualities, it might be best to look somewhere else.

Once you’ve selected your potential convert, introduce him or her to free software on the Windows platform. It’s likely that he or she is already using Firefox (if it’s an IE user, you might want to pick someone else to convert), but there’s a chance that he or she doesn’t realize that it’s free software. Drop a hint about how Firefox was written the same way Linux is written; by a community of developers, rather than by a giant corporation. Explain why you think this is better: more eyeballs equals fewer bugs, more features, and more developers. For a full list of free software that runs on Windows, check out this page.

One of the reasons that people get the “gotta have it” syndrome over Linux is the eye-candy of the Compiz-enabled desktop. Sure, it’s superficial, and we all know that there’s more to Linux than just a rotating cube and windows that minimize in a ball of fire, but it’s a great way to quickly grab someone’s attention and get them asking questions. “What is that?” “How did you do that?” “How can I get that?” Your answers for all of these questions will be points towards Linux.

You don’t want your to-be-convert to rush into things and get frustrated. This is a quick and easy way for them to go running back to Windows. Instead, give them a LiveCD; it’s a great way for them to become familiar with the Linux desktop, the interface, and the features included in the installation. Think of it as a toy that they can play with in their spare time. Don’t push it on them, just say “if you want to check it out, you can boot off this CD without making any modifications to your hard drive.” It’s a great way for the mark to get their feet wet.

Hopefully, your mark has been impressed with what he’s seen on the LiveCD, and is ready to take the initial plunge. Great for him! Encourage him that it’s really no big deal. Walk him through the installation, and explain that he can keep his Windows partition and duel-boot with Linux, picking whichever he prefers to use at the moment. This is a great way for people to slowly become accustomed a new operating system. It’s imperative that you be around to help out the new user. The most important thing about Linux is that it has great community support – by sticking around and being a helpful hand, you’re encouraging your mark to use community channels to find solutions to problems.

Again, you must, must, must remain helpful even after the operating system is installed, but let the new-convert try to figure things out on her own. Let her find her way around the desktop, check out the included programs, browse the web, and do the things she wants to do with her computer. Your job now is to sit back and just remain available when she has questions. Show her how to add and remove software; recommend programs when she asks, “what program do I use to do [insert task here]?” But throughout all of this, let the new user do her own thing.

If all goes well, the newly-converted user will be enjoying her first Linux experience. But of course, there will be problems. Remain available to help work her through the tough times and the initial shock of a completely new desktop experience, but don’t force your advice when you aren’t asked.

This is a good time to start explaining other ways of getting help with Linux. The idea here is to make the user self-sufficient in trouble-shooting and problem solving, but still try to be the most valuable resource you can possibly be.

If your convert is still using her new Linux desktop at this point, it’s probably safe to declare success! Congratulations! You’ve turned someone on to a free-software operating system. By this time, her desktop should probably be well-configured, and all the programs she needs should be installed and working properly. By this time, you’ll probably be starting to get more advanced questions than before; things like, “How do I customize function [x]?” or “What does it mean when the update manager does [something]?” If you’re lucky, you’ll know all the answers; otherwise, use these valuable resources to find out some solutions! It’s always important to learn more yourself, so that you can proceed to step 10:

If you’ve been lucky enough to successfully convert a Windows user to Linux, you should definitely try it again with someone else! Use what you’ve learned with your previous experience and adapt it to fit your style and your mark. If all goes well, you should have your own personal army of Linux converts in no time at all!

Web 2.0 was marked by the development of web-based applications. Things really took off when “mashups” began to appear; the ability to take information from multiple sites and create a unique service, based on the web, that provided a sum greater than the whole of its parts. But the major limitation to all these services is that they existed solely in the realm of the Internet, and data was stored on somebody else’s servers.

The introduction of Ajax Runtime Environments is poised to change all that. Adobe’s Air platform and Mozilla’s XULRunner allow coders to write applications using the technology of Web 2.0 – XML, Ajax, and Javascript – and transfer what was once a web-only platform to the user’s desktop.

Traditionally, Web 2.0 applications were limited to content already in existence on the web. They relied largely upon user-uploaded content to various sites (Flickr being a great example), as well as the large databases maintained by corporations (Amazon.com’s API, which allows you to query their products, being a good example of this).

These desktop-based applications will still have access to this web-based content, but it is also able to utilize what’s most important to the user – the files located on his or her desktop and local network. Combining this data with the information stored can bring about limitless possibilities.

A quick example: imagine an application that can sort and browse through the photos you took on a recent trip to Spain. The application then queries Flickr for other people’s photos of the same locations; together, you now have not only your own photos, but access to pictures taken by the entire web community. Another example: you have an application to manage your personal book collection. This web-enhanced app, running on your desktop, is now able to lookup what books you might like to read, based on recommendations from Amazon.com and other sites. The possibilities are endless.

We’ve already seen the beginning of such programs. Miro, an application for downloading and watching internet-based TV, uses the Mozilla XULRunner Runtime Environment. Songbird, an iTunes-like music player, also utilizes the XULRunner environment. Joost, an application similar to Miro, was created by the founders of Skype and Kazaa, and uses p2p technology to distribute vidcasts over the internet. All of these applications have a few key things in common: they run on the desktop, they are cross-platform, easy to develop, and can easily leverage the full power of the Internet to deliver content and an experience not limited by the traditional methods of desktop-based programs.

Like the emergence of Web 2.0, it’s impossible to tell where things will end up going. But the possibilities of combining the desktop with the collective resources of the Internet-at-large are seemingly endless. My prediction is that we’ll see applications that become as integral a part of our computing experience as services like Gmail and Flickr have become in the past few years.