#Multi-speed
3 messages in this thread
He probably means when the head is reading from the inside track
(sector zero), that the disc spins at 530 rpms and 200 rpms when the
head is at the outer most track.
In any case. All CD-ROM drives read data off the disc while the bits
pass under the head at a constant speed. This requires the drive to
decrease the disc's rotational speen as the head moves from the
inside tracks to the outside tracks.
Double speed and quad-speed drives are those which spin the discs at
double or quadruple the speed of normal drives. This leads to an
increased data transfer rate as far as we're concerned.
Roger…
Thanks… I was just teasing him, as some users might get confused if they
didn't know about the drive changing the disc speed… (only fun intended…
<g>)
Yours,
Bryan
And to think that someone could consider one disc spinning at
different rates at the same time. AT the beginning of the disc the
rate is fixed until the servo locks in. When the pickup is tracking
the outside tracks near the end the RPM is slower. At stadard speed
the data sectors are coming off the disc at 75 per second. The magic
buffer size is one that contains a full disc revolution at the outer
edge of the disc. Bigger doesn't seem to buy much. Double speed can
reduce the time to read sectors at the outer edge as well as improve
transfer rate.