[aclug-L] Re: CD-ROM drive speeds

["Dale W Hodge" <dwh@xxxxxxxxxxxxxxxx>]

> Oddly enough, my 12x CD drive (w/ 4x write capability) seems to be about 3
> times faster than my 24x CD drive at reading audio CDs (w/ cdparanoia).
>
> However... it seems that the 24x drive is faster than the 12x drive with
> data CDs (although I have not benchmarked this yet--I suppose I should).
>
> Both drives are SCSI.  The 24x is made by Sony, the 12x is made by Teac.
>
> Is it normal/possible that a CD drive's audio reading speed is entirely
> different than it's data reading speed?

Yes, entirely.  Some CD drives (mostly older 1x & 2x) do not even support
digital audio extraction (DAE). Remember, the specification for CDROM drives
allows for the playback of digital audio in hardware, without support from
the host computer.  DAE is a means of side stepping this feature and reading
the audio data directly off the digital bus. The CD Data spec provides for
some error checking that the CD audio spec does not. The faster the disc
spins, the more likely it is to produce errors in DAE. Past a certain point,
faster is not better.

--dwh

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Dale W Hodge * dwh@xxxxxxxxxxxxxxxx * dwh@xxxxxxxx * dwh@xxxxxxxxxxxxxxxxxx
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