Re: Identifying CD drives across reboots
Re: Identifying CD drives across reboots
- Subject: Re: Identifying CD drives across reboots
- From: Stephen Hoffman <email@hidden>
- Date: Mon, 24 Dec 2007 10:37:39 -0500
- Organization: HoffmanLabs LLC
Stephen F. Booth wrote:
I need to identify the drive in order to determine (and store) the
drive's read offset. To preempt your next question: I need to do this
to accurately access CDDA in a device-independent manner. :)
Consider spinning up the media in the drive and ask for the media ISRC,
or whatever media-level identification is present on the particular
flavor of CD you're working with. Compare this against the expected and
known values in your database, and jump to the right sector.
Remember that drives won't get insulted if the application chats using a
command subset, but the drives do throw a snit if they don't understand
what the application has asked, or don't offer the particular command or
feature. Worse, some drives can and do become catatonic when they get
confused, and some become solidly confused quite easily.
I'd not bother looking for a unique drive serial number or trying to
aggregate and synthesize such based on model and vendor. What happens
if you're dealing with a tower of identical drives, for instance? The
ISRC is probably your best bet here, based on your stated goal.
Do you have access to the Red, Yellow and Orange books? These and the
T10 and T13 documents are soon to be your friends. (And for anyone just
getting their tootsies wet in this area, find and start with the
INF-8020/SFF-8020 document. 8020 is long retired and long superseded,
but it's one of the few good classic introductions to CD operations
around.) Drives also tend to be creative about the parts of and the
revisions of T10 and T13 implemented.
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