Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!apple!ntg!dplatt
From: dplatt@ntg.uucp (Dave Platt)
Newsgroups: comp.sys.mac.hardware
Subject: Re: Reviews of Non-Apple CD-ROM drives (Summary)
Message-ID: <50@goblin.ntg.uucp>
Date: 9 Apr 91 18:05:18 GMT
References: <7188@mace.cc.purdue.edu> <1991Apr8.205628.28550@cs.ucla.edu>
Reply-To: dplatt@ntg.UUCP (Dave Platt)
Distribution: usa
Organization: New Technologies Group, Inc.  Palo Alto CA
Lines: 63

In article <1991Apr8.205628.28550@cs.ucla.edu> tj@kona.cs.ucla.edu (Tom Johnson) writes:

>If you are using it purely for data, it's works fine.  The drive is indeed
>faster than the Apple, and we have had no compatibility problems
>with it whatsoever.
>
>If you are using it for playing audio CDs, watch out.  The Toshiba driver,
>does not support all of Apple's music calls.  You have to use Apple's
>CD Remote desk accessory and INIT to play disks, but you can't scan
>thru the disk (no fast-forward or rewind). You can jump to different
>tracks, if you wish, you just can't fast-forward into the middle of 
>a track.

That's not the fault of the driver... not really.  The Toshiba XM-3201
mechanism doesn't support a fast-forward or scan-backwards command via
the SCSI interface.  It might be possible for the driver to emulate the
effect, in a crude fashion, by reading the current disc time, stopping
the play operation, and then restarting play at a slightly different
time.  This would probably cause a rather abrupt, jarring effect... not
really what you'd want to hear.

>         Other driver calls do not seem to be supported as well, the
>GetMusicStatus (or whatever it's called) control call consistently returns
>bad information about the actual status of audio play.

Once again, this isn't really the fault of the driver... the Toshiba
returns different information in the playback-status byte than the Apple
drive does (and it apparently doesn't return all of the possible
status codes that the Apple drive can support).  Perhaps the driver
could do a better job of mapping the Toshiba status codes to the ones
that users of Apple drives would expect.

The Toshiba's status codes are 0x00 for "PLAY in progress", 0x01 for
"STILL operation issued" (user PAUSE, I believe), 0x02 for "AUDIO TRACK
SEARCH with PLAY=0 issued" (locate a track and then pause), and 0x03 for
other statuses (e.g. "audio play complete")

>All in all, I would never buy another Toshiba drive.  I don't think that
>the overall hassle (and the lack of confidence I now have in the companies
>Macintosh products) would offset the small performance increases and the
>very slight monetary savings.

Well, I've come to a different conclusion... which perhaps reflects the
different use I make of the drive.  My XM-3201 has been completely
reliable in the 18 months I've owned it.  It's a _very_ effective CD-ROM
drive, and it works quite adequately on the occasions that I use it to
play audio discs.  It has been able to play, without the slightest
hiccough, a couple of off-spec discs that my primary CD audio player had
difficulty handling.

The underlying technical issue is, I think, that the Apple and Toshiba
drives have slightly different command sets and status responses.  This
is due, I think, to the fact that the SCSI-1 standard did not include a
command-set for CD-ROM drives, and so each vendor was forced to invent
one.   The newer SCSI-2 standard does define a common language for
CD-ROM drives, and the next generation of such drives will probably be
much more intercompatible.


-- 
Dave Platt                                                VOICE: (415) 813-8917
                    UUCP: ...apple!ntg!dplatt
 USNAIL: New Technologies Group Inc. 2468 Embarcardero Way, Palo Alto CA 94303