Okay, I’ll bite.
What I need is a simple way to decide if a ROM drive supports
MMC-2 or only MMC-1 commands and if the drive is a CD-ROM or
a DVD-ROM drive.
I’ll answer the second question first: Look at the CD Capabilities Mode
page (2A), byte 2, bit 3 (the DVD-ROM Read bit). If it’s set, the drive
can read DVD-ROM. Keep in mind that some drives can read both DVD and
CD, so don’t assume that if bit 3 is set, the drive can’t read CDs.
The answer to the first question is nastier: There is no simple way to
tell if a drive supports MMC-1, -2, or -3 (or any of the above). You
can’t send a specific MMC-2 command hoping for a 5/20/00 (Invalid
Operation Code) to be returned because some early drive firmware writers
were lazy and simply ignored commands they didn’t support - no Sense
code, no nothin’. Nice way to hang the machine, that. Luckily, recent
drives don’t do that. In general, the only way to really know is to
have a list of drive inquiry strings and what level of MMC (if any) they
support. It sucks, but there it is.
Well, I suppose that if the drive supports DVD, you can make the
assumption it supports at least MMC-2. With CD drives, though it is
just not that simple.
If someone else knows a better answer to the MMC question, I’d love to
hear it.
Uh, and be sure to go get copies of the MMC-1, -2, and -3 specs –
you’re going to need them.
Stu Bell
Senior Software Engineer and Driver Wrangler
Roxio, Inc.
xxxxx@roxio.com
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