How can I use the iPod as a hard disk?

To use the iPod as a hard drive, you will need to "enable disk use" in iTunes and connect the iPod to your computer (please note that the iPod touch models officially do not support disk mode, although third-party software is available). When disk use is enabled, the iPod appears as any other disk on the Mac desktop or within My Computer on Windows, and you can drag-and-drop files from the hard drive to the iPod or vice versa. For additional information, please refer to "Using Your iPod as a Storage Drive" from the Apple Support Site.

Can I start up my Mac or Windows computer using the iPod?

You can use the iPod to start up a Mac, although the official information provided by Apple is a bit contradictory as to whether or not it is a good idea.

The official Apple iPod FAQ states:

iPod can be loaded with system software and used as a startup disk for your Mac or to install system software on your Mac. Using iPod to start up your Mac with system software is an unsupported feature. iPod cannot be used to start up a PC.

However, "unsupported feature" links to another document titled "Don't Use iPod as a Startup Disk" that simply states "though your computer might recognize iPod as a possible startup disk, Apple does not support using it as a startup disk. You can store all kinds of files on iPod, even system software, but you shouldn't use iPod as a startup disk."

The official Apple iPod FAQ is referring to Firewire-based iPods. USB-based iPods, which include all currently shipping models, are not intended for use as a MacOS X startup disk even as an "unsupported feature". For additional information, please refer to "Don't Start Up from an External USB Device" from the Apple Support Site.

However, Rentzsch, an author for the respected TidBits publication, has reported that you also can boot a computer running MacOS X from an external USB drive as well.

Ultimately, many iPod models will function as a MacOS X startup disk, which is extremely useful for troubleshooting, but Apple most likely recommends against it as the iPod could overheat.

Also see: Which iPods can sync and charge via USB? Which iPods can sync and charge via Firewire?

What operating system does the iPod use? Does it run MacOS X?

According to San Francisco Chronicle article "Little-known startup was behind iPod's easy-to-use interface", all versions of the iPod -- except for the iPod shuffle -- released prior to September 5, 2007 use an operating system derived from Pixo OS 2.1, originally designed for use with cell phones and other handheld devices.

The iPod models introduced on September 5, 2007 -- the iPod classic (6G/Original), iPod nano (3G/Fat), and iPod touch (Original) -- as well as subsequent models use an operating system that derived from the version of MacOS X used on the iPhone.

Can I run Linux on my iPod?

Obviously, Apple provides no support for running other operating systems on your iPod, and attempting to do so likely will invalidate your warranty. Consequently, EveryiPod.com does not recommend or endorse using other operating systems on the iPod.

However, for the truly adventurous, please refer to the iPodLinux Project for instructions on how to install Linux on the iPod. The wiki provides the current level of compatibility for each iPod model.

One reader reported that he "has a friend who runs Linux on his iPod and it prevents it from sleeping and wears down the battery even while charging." This likely is due to the lack of power management as acknowledged on the iPodLinux Project website.

Should you decide to experiment with an older iPod and install Linux, please be careful, follow instructions carefully, and back up all data before attempting this hack.