Hi Robie,
[EMAIL PROTECTED] writes:
> To anyone familiar with QIC-113g (possibly just Claus):
>
> I just got to writing the code which locates the directory section of
> the volume, and I think I've come across a problem. Could someone just
> check a bit of the specification for me, and check if I'm right?
>
> From QIC-113g, section 7.1.1 (bottom of page 14):
> When the bit [directory last] is set the File Set Directory shall
> be segment aligned and located by subtracting the Directory
> Section Size (offsets 92-95) rounded up to an integral number
> of segments from the Ending Segment Number (offsets 6-7). This
> is to accomodate finding the start of the Directory Section.
>
> "rounded up to an integral number of segments" is very confusing. Do I
> assume a segment size of 32K, 29K, or work it out for each individual
> segment (the Directory Section Size is specified in bytes)?
Surely they mean 29k - #bads (where #bads is the number of bad sectors).
> Question: algorithm for locating the directory section segment starting
> number?
> Problem: segment sizes vary. If there are too many bad sectors there,
> then I'll get the wrong segment.
> I could account for bad sectors to locate it, but who knows whether
Right. Take the directory section size. Then take the data size of the
last segment of the volume and subtract it from the directory segment
size.
Continue with the pre-last segment (and so on) until the result
becomes <= 0.
> 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.
> 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
:-)
Claus
--
Claus-Justus Heine
[EMAIL PROTECTED]
http://www.instmath.rwth-aachen.de/~heine/
Ftape - the Linux Floppy Tape Project
Home Page : http://www.instmath.rwth-aachen.de/~heine/ftape/
Mailing-list: [EMAIL PROTECTED]
