[78-L] Record playing speed ^

[Chris Zwarg]

At 16:22 03.12.2008, you wrote:
>Ok there were 80, 78, 33 1/3 then 45 and even 16 rpm (my aunt had one of these).
>
>But, is there a standard spining speed on a CD? (what does it mean 1X, 2X, 16X, etc. in the CD-ROMS?)

The rpm varies greatly from center (start) to edge (end) in such a fashion that the linear speed along the track is constant. "1x" is the speed used for audio CDs, i.e. circa 80 minutes for a well-filled CD. "2x" is double-speed, i.e. circa 40 minutes, etc. For practical purposes, the higher settings (above 16x) are not quite realistic, as there are other factors beyond the mere data-transfer involved (e.g. writing lead-in and lead-out data on the recording side, and accessing particular small files on a CD-ROM) which don't speed up as well, so the given speed is a rather theoretical value assuming you are writing/reading one continuous 700MB file to/from the disc.

Chris Zwarg