Firewire Target Disk Mode
FireWire Target Disk Mode is a commonly used feature in troubleshooting. In a nutshell, Open Firmware and the FireWire components of your Mac work together to turn the machine into an external FireWire drive, making it available to other computers and devices in the chain, just as if it were a mass storage device.
Usually, Target Disk Mode is used to pull data in a hurry from a crashed computer, install Tiger on a nonofficially supported machine (not that you would want to do that, of course), or as a powerful way to hack data from a password protected machine—but luckily FileVault has come to the rescue over the past few years.
There are, however, more productive usages of Target Disk Mode that are often overlooked. For example, if you have a desktop Mac and a portable, keeping the two in sync can be a pain. With a simple cloning tool such as Carbon Copy Cloner , you can transfer everything from one Mac to the other in a matter of minutes.
Of course, doing so requires that both hard drives be more or less the same size (you obviously can't clone an 80GB hard drive into a 20GB one) and you might run into the occasional glitch as your desktop Mac probably isn't configured to manage the hardware your laptop will include, such as a battery or maybe an AirPort card. Light configuration will be required and the resulting clone might not be the most stable of setups.
For example, don't expect all your serial numbers to work on the cloned machine, and don't try to edit the next blockbuster in FinalCut pro on your blueberry iBook. Nevertheless, as a quick and dirty panic-relief situation, it does work perfectly well, and I have used it many times in the past when attending conferences where I just wanted to take notes, chat a bit, and check my mail periodically, while still keeping my articles and mail archives at hand.
Recycle Older Drives
After reading articles lately on the importance of scrubbing hard drives before selling them, maybe you no longer feel like including a drive in the PC (if you're a switcher) or PowerMac that you're letting go of. What should you do? Stick the old hard drive into your new Mac? Hmm, maybe you don't have enough space (if you replaced your PowerMac G4 with an iMac G5, for example) or the drive doesn't conform to the new specifications.
In many cases, older drives can be repurposed in external FireWire enclosures. While the resulting device might not be the fastest of your peripherals, the extra drive may come in handy for backups and other housekeeping duties.
If you decide to investigate that option, though, please do invest in a high-quality case, as you want to entrust your data only to the best chipsets and firmwares. The Apple Discussions, notably the forums concerning older machines, can be a good starting point for such a project, as you will be able to interact with users who have faced similar questions.
Use FireWire to Talk to Your TV
Many TVs and set-top boxes now ship with FireWire interfaces to stream data, receive information, and talk to other pieces of equipment in your home theater system. Since these devices comply to the FireWire standard, you can plug them into your Mac and they will start talking to each other.
Now, how does your TV make sense of what your Mac does? Simply by using an application on your Mac that sends signals to the TV that it understands: the same that would be sent over the same link by a camcorder or an entertainment unit. Some commercial solutions have begun popping up that do just that, but the open source community is already at hard work creating such applications that can turn your Mac into a full-featured remote control for your TV, recording device, and media center. Of course, some antipiracy (i.e. vendor lock-in) technologies that are now commonly embedded in TVs can interfere with that process but, in many cases, there is plenty left to do.
A good introduction to this use of FireWire is Build Your Own PVR (for free) with HackTV by Erica Sadun.
Get Familiar with Developer Tools
Like with many great technologies full of potential, there are many tools that take advantage of its cool features but that cannot be officially supported, because they're not stable enough, for example. This is why I encourage you to go to the Apple Developer Site and download the latest version of the development tools. You will find a wealth of FireWire-related utilities and applications that can be compiled in Xcode, ready for you to play with. One important word of caution: don't start playing at a hardware level unless you know what you are doing or are ready to face the consequences of a glitch; some of these utilities can cause issues if used improperly.
I've just scratched the surface of what makes FireWire great and why it's a promising, fundamentally useful technology. I hope these few pointers will encourage you to play more with this excellent technology. There's a lot to do with FireWire and, as more developers jump on board (Remember, this is the year of HD!), we should see some very interesting devices and ideas appearing over the next months.
FJ de Kermadec is an author, stylist and entrepreneur in Paris, France.
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