From an Apple press release for the 1st generation iPod:
"Ipod puts 1000 songs in your pocket
October 23, 2001—Apple today introduced iPod, a breakthrough MP3 music player that packs up to 1,000 CD-quality songs into an ultra-portable, 6.5 ounce design that fits in your pocket. iPod combines a major advance in portable music device design with Apple’s Auto-Sync, which automatically downloads all your iTunes songs and playlists into your iPod, and keeps them up to date whenever you plug your iPod into your Mac. iPod represents the next generation of portable music players that store music on an internal hard drive, yet are only 20 percent of the volume of today’s hard drive-based players. iPod stores up to 1,000 CD-quality songs on its super-thin 5 GB hard drive, and features up to 20 minutes of shock protection for nonstop playback when running, biking or other activities...."