Compact Disc-Read Only Memory is an optical storage medium which are physically the same as audio CDs, but their players are specially configured to access information faster than audio CD players, and are also able to read data non-sequentially, since hypermedia is essentially a non-sequential system. CD-ROMS store a greater amount of data than is suitable for a 3.5" floppy disk - about 650 Mb, which is equivalent to around 450 floppy disks at 1.44 Mb each. Combined with compression techniques, it is now possible to store a complete video in the same space which would have previously been taken by audio only. Technology has progressed so that DVDs (Digital Video Discs) can store entire feature films in crystal-clear visuals and CD-quality sound, along with interactive features such as menus, languages and instant chapter access. The DVD is a step beyond the Beatles" Hard Day's Night CD-ROM, since it can store 4.7 Gigabytes (thousands of Megabytes) of information - as much as six CD-ROMS or 2500 floppy disks!

CD-ROMS are faster at accessing data than the Internet. A double speed CD-ROM drive delivers data around 150 times faster than a modem, and around 20 times faster than ISDN. The fastest CD-ROM drives transmit data at least four times faster than T-3, currently the fastest connection to the Internet.

At the end of 1994 it was estimated that there were around 13 Terabytes (thousands of Gigabytes) of information on the WWW - around 20 000 times as much as a single CD-ROM, but for a project such as the Welsh Pop Music Resource Pages, a CD-ROM is an ideal medium of storage since it allows instant access to subsequent pages, leading to an efficient execution of information and a faster reading time for the user.

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