Re: SCSI-2 CD-ROM drivers

[dempson@actrix.gen.nz (David Empson)]

"Joel" <joelbuckley54.nospam.@hotmail.com> wrote:

> I have Apple CD-150, CD-300 and CD-600 drives.
> They all work for data reading, but only the CD-150 works for CD-Remote
> audio play and the program controlled eject function.
> I get the impression from reading the FAQs that I need a SCSI-2 driver to
> support these functions.
> It refers to one by Sequential Systems.
> Their web site www.sequential.com doesn't seem to be up.
> Is it available anywhere?

No.  As far as I recall, Sequential Systems announced that they would be
releasing a driver for Apple SCSI cards to support the SCSI-2 audio CD
command set, but it was never released.

> What exactly does it do that the standard driver doesn't?

It was supposed to be a driver for the Media Control toolset, which
would have allowed the use of the Media Remote NDA to control playback
of an audio CD in a CD-ROM drive on an Apple High-Speed or rev C SCSI
card.

In Apple's early CD-ROM drives (CD-SC, CD-SC+ and CD-150), they used a
proprietary command set which was unique to Apple.  Support for this
command set is built into the firmware of the Apple SCSI cards, the
GS/OS SCSI CD-ROM driver and in the CD Remote NDA.  Apple used a
proprietary command set because the SCSI-1 standard didn't include
commands for controlling audio CDs.

The SCSI-2 standard introduced a standard set of commands for
controlling audio CD playback, which is incompatible with Apple's
proprietary command set.  For the CD-300 and later models, Apple
switched to the new standard command set, and no longer supported their
earlier proprietary command set.  They updated the Mac drivers to
support the new command set, but left the Apple II in limbo, only
supporting the older command set (and hence the older drives, if you
want software control of audio CD playback).

There is no problem dealing with data CDs in newer CD-ROM drives, since
that part of the SCSI command set is the same for older and newer
models.

-- 
David Empson
dempson@actrix.gen.nz