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SubjectRe: SONY or CD-ROM lying about speed?
Thierry Danis wrote:
>
> On Sat, Feb 06, 1999 at 04:37:34PM +0100, Jon K Hellan wrote:
> > I have a SONY 32x CD-ROM CDU771. However, Linux reports it as 14
> > speed. Apparently, FreeBSD does the same.

The PIDENTIFY_DEVICE command is sent to the drive,
and one of the data fields returned is "drive maxspeed"
which in this case the drive sets to "14 x 176KB/sec"
(176KB/sec = 1X or "original" CD speed).

Linux just displays what the drive told it.

> I've seen the same. Running a 'dd' over a complete CDROM
> gives me a transfer rate around 2100 KB/s, which is x14.
> I have a CD-ROM CDU701.

Note that the "maxspeed" only applies to a small zone on the outer
tracks,
which is why cdroms are now advertised as "up to 32x" rather than "32x".
The *average* over the whole drive will be much lower than the maxspeed.
--
mlord@pobox.com

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