2010年8月2日 星期一

iPod Classic History

iPod Classic
is a portable media player marketed by Apple Inc. To date, there have been six generations of the iPod Classic, as well as a spin-off (the iPod Photo) that was later re-integrated into the main Classic line. All generations use a 1.8-inch hard drive for storage.


The "Classic" retronym was introduced with the introduction of the sixth-generation iPod Classic on 5 September 2007; prior to this, an iPod Classic was simply referred to as an iPod.
 
 
 
 
FIRST GENERATION                                             
 
 
 










                                                                                                                                  October 23, 2001













Second generation


 
 
 
 
 
 
 
 
 
 
 
                                                                                                                                   In JULY 17, 2002
 
 
 
 
Third generation
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                                                                                                                         April 28, 2003
 
 
 
 
 
 
 
Fourth generation
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                                                                                                   July 19, 2004
 
 
 
 
 
 
 
Fifth generation
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                                                                                                         October 12, 2005,
 
 
Sixth generation                                                                                                     
 
 
                                                                                                                      September 5, 2007
 



 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Operating system and firmware


The iPod's operating system is stored on its dedicated storage medium. An additional NOR flash ROM chip (either 1 MB or 512 KB) contains a bootloader program that tells the device to load its OS from the storage medium. Each iPod also has 32 MB of RAM, although the 60 and 80 GB fifth generation, and the sixth generation models have 64 MB. A portion of the RAM is used to hold the iPod OS loaded from firmware, but the majority of it serves to cache songs from the storage medium. For example, an iPod could spin its hard disk up once and copy approximately 30 MB of upcoming songs into RAM, thus saving power by not requiring the drive to spin up for each song. Rockbox and iPodLinux offer open-source alternatives to the standard firmware and operating system, respectively. However, at the current time these are both unavailable for use with the 6th generation iPod Classic due to encryption used on the official firmware.

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