On Sun, Jul 30, 2000 at 05:55:09PM +0200, Claus-Justus Heine wrote:
[...]
> [EMAIL PROTECTED] writes:
[...]
> > I could account for bad sectors to locate it, but who knows whether
> > other implementations account for it?
>
> Nobody. You have to test it. Or ask Iomega, Seagate or whoever to
> enlight you.
Unfortunately, Iomega are hiding behind an NDA, and Tecmar have been
very willing to help, but they contract the software to Vertitas who
certainly won't be.
> > It would be nice if someone could point out that I'm just being
> > braindead :-)
>
> That's very tempting. But I think I'd better be not THAT nice to you
> :-)
IMHO this is a flaw in the specs, although it can be worked around.
I've been compiling a list of "features"; I'm going to suggest a
revision h, where the segment number of the directory section will eat
up another four bytes off the vendor extension field.
I'll wait, though, until I've finished my program; who knows what else
I'll come up with. :-)
On Sun, Jul 30, 2000 at 01:10:11PM -0500, Daniel J. Gardner wrote:
[...]
> A) No two vendors implement QIC-113 the same.
> B) Many times there are variations from the same vendor.
> C) Trying to write generalized code to handle all variations is a nightmare.
>
> I would be more than willing to help whenever I can.
You're absolutely right; the specifications themselves allow for many
variations; I've _finally_ come up with some almost-neat looking code
which handles segment-spanning, non-segment-spanning and uncompressed
volumes gracefully and transparantely, but it did take a lot of
head-scratching :-)
And only _then_ do I realize that compression frame sizes are limited
to 64K even on segment spanning volumes :-( Makes me wonder what the
point of non-segment spanning volumes is, anyway.
I'm beginning to think that doing the writing support first might have
been easier, as I only have to write it one way; what put me off was
the compression algae-rhythm :-)
Only now, when half the reading code's in place, does it occur to me
that I don't need to do compression :-(
Two items of help I can think of:
1. A name! I still haven't thought of a decent name for this program
:-)
2. I'll need _lots_ of testing, as multiple software writes it in
multiple ways. This, of course, will have to wait until the code
actually compiles and does something :-)
[...]
Also, can anyone give me a hint as to SCSI support? The specs allow
for SCSI, but I don't know how many programs there are "out there"
that actually use QIC-113. Also, what about IDE?
Are segment sizes limited to 29K on these as well? I'll need ioctls or
otherwise to be able to retrieve segments by number, and also know the
size of a segment given the number (which the bsm handling in libftvt
gives me currently).
Claus: If I support SCSI, libftvt will need it's tape I/O encapsulated
so that SCSI calls can be made as well. Thoughts?
Robie.
--
Robie Basak <[EMAIL PROTECTED]>
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