Software
iPod Capabilities include playing:
1. MP3 audio file formats.
2. WAV audio file formats.
3.M4A / AAC LC audio file formats.
4. Protected AAC audio file formats.
5. AIFF audio file formats.
6. Audible audiobook audio file formats and
7. Apple Lossless audio file formats.
iPod capabilities of the 5th generation version plays .m4v and .mp4 MPEG-4 video file formats.
Microsoft Windows version of iTunes can transcode regular non copy-protected WMA files to an iPod supported format. WMA files with copy protection cannot be played in iTunes or be copied to an iPod.
What I do not like about the iPod is the inability to play some other formats, in particular the Ogg Vorbis and FLAC formats. MIDI files cannot be played on iPods as well, but can be converted into a compatible audio file format by choosing the "advanced" menu on iTunes.
Apple has designed the iPod to work with the iTunes media library software, which lets you manage your music libraries on your computer and on your iPod. iTunes can automatically synchronize your iPod with specific playlists or with the entire contents of a music library each time you connect your iPod to a host computer.
You can also set a rating (out of 5 stars) on any song, and can synchronize that information to an iTunes music library. iTunes lacks the ability to transfer songs from iPod to computer because of legality issues.
However, several third-party programs exist that provide music synchronization facilities similar to iTunes, but also offer the ability to copy music from iPod back to your host computer. Notable examples include vPod and the Ml iPod plugin for Winamp.
iTunes Music Store
The iTunes Music Store (iTMS) is an online music store run by Apple and accessed via iTunes. It was introduced on 28 April, 2003 and sells individual songs relatively easily and cheaply (e.g. 0.99 USD, 0.99 Euro, 0.79 GBP).
iPod's are the only portable music player that can play the purchased music, and this exclusiveness has
helped the store become the dominant online music service.
The purchased audio files use the AAC format with added encryption. The encryption is based on FairPlay Digital Rights Management (DRM) system. Up to five authorized computers and an unlimited amount of iPods can play the files.
Burning the files onto an audio CD removes the Digital Rights Management (DRM), at a cost of reduced quality when re-compressed from one lossy format to another.
iPods cannot play music files encrypted with other rival Digital Rights Management (DRM) technologies,
such as Microsoft's protected WMA or RealNetworks' Helix-DRM.
Hardware
iPod capabilities was to connect it to a user's computer to update songs and recharge its battery solely through FireWire originally. It could also be charged by connecting it to a small power adapter which are shipped for free with several of the first generation iPod’s.
The now standard dock connector was not added until the 3rd generation in April 2003, allowing users
the option of using FireWire or USB to make data transfers, although the device could still not be charged by USB and the USB cable was not included.
Most PC's don't have FireWire ports so this move effectively opened the Windows market to iPod, although USB only Windows users had to keep their FireWire cables to plug into the wall adapter.
The dock connector also made it possible to transfer data, sound, and power back and forth to iPod accesories, which created an explosive market of devices that has been extremely profitable for third parties such as Belkin and Griffin. The resulting myriad of connecting devices is still one of iPod's greatest strengths over its competititors.
iPod capabilities of the 4th generation version could be charged with USB, and eventually Apple started shipping iPods with USB cables instead of one's with FireWire. Many Macs shipped before 2004 had only USB 1.1, which has a transfer speed of 11 Mbit/s, as opposed to FireWire's 400 and USB 2.0's 480.
Although none of these actually transfers at these exact rates, USB 1.1 is much slower than the other two, and for some USB 1.1 may simply be unusable for transferring music collections to fill a 40 GB iPod. Later introductions has continued to lessen iPod's reliance on FireWire.
iPod Shuffle, released in January 2005, plugs directly into a USB port, without a dock connector and has no Firewire support. The iPod Nano, released in September 2005, uses a dock connector that allows a FireWire cable to be plugged in to charge the device, but not to transfer data. With the 5th generation iPod, Apple dropped all support for data transfer over Firewire to any model iPod.
Like the Nano, the 5th generation iPod's dock connector will accept a FireWire cable and can draw power from it, but only the USB connection, not the one with FireWire, will support data transfer - a message stating this appears on the iPod screen.
This has drawn some criticism from the Mac community, since FireWire has been a standard feature on Apple Macs for many years, while USB 2.0 support was only added in October 2003.
The first three generations of iPod used two ARM 7TDMI-derived CPUs running at 90 MHz, while later models have variable speed chips which run at a peak of 80 MHz to save battery life.
The iPod use 1.8 inch (46 mm) ATA hard drives (with a proprietary connector) made by Toshiba and the iPod Mini uses one-inch Compact Flash microdrive hard drives made by Hitachi. It has a 32 MiB flash ROM chip which contains a bootloader, a program that tells the device to load the operating system from another medium (in this case, the hard drive).
All iPods, except for the 60 GB 5th generation version, has 32 MiB of RAM, a portion of which holds the OS loaded from the firmware and the vast majority of which serves to cache songs loaded from the hard drive.
For example, an iPod could spin the hard disk up once and copy about 30 MiB of upcoming songs on a playlist into RAM, thus saving power by not having the drive spin up for each song. (The 60 GB fifth-generation iPod holds 64 MiB of RAM, to further extend battery life.)
iPod was originally introduced with a black and white display but no current model uses one. iPod Photo (an addition to the functionality of the 4th generation iPod released in late 2004) introduced a color screen, while iPod shuffle (released January 2005) has no screen at all.
When iPod Mini was replaced with iPod Nano it received a colour screen (and photo capabilty) and starting with the 5th generation all full size iPods have color screens and photo capability.
http://www.content.onlypunjab.com/Article/iPod-Capabilities/4200320092003250259
