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SubjectRe: [PATCH] zip drives
On Wed, 15 Mar 2000, Manfred Spraul wrote:

> From: "James Sutherland" <jas88@cam.ac.uk>
> > > Gadi Oxman writes:
> > >
> > > > Another point to add is that some (newer?) ZIP drives have a jumper
> > > > on them which enables some cheat mode for MSDOS which actually hides
> > > > some sectors from the device driver.
>
> Both WinNT and Windows 95 need the cheat mode: IIRC they don't analyze the
> partition table if the device reports itself as ATAPI FLOPPY.

Oh dear.
#include <broken-code-rant.h>

OTOH, why would/could a floppy contain a partition table?

> > > > That is, block 0 on the drive
> > > > actually moves along with the partition table, and perhaps also the
> > > > reported capacity.
> Fixed 32 blocks, they don't analyze the partition table.
>
> > [...]
> > Load first sector. Is it an MBR/partition table, or a boot sector?
> > If the former, add an offset of 32 sectors to all subsequent accesses.
> > This way, we get consistent behaviour from both types of drive.
> > You then always mount /dev/sda (or whatever).
>
> What if you have a partition table with != 32 sectors? Just try to mount an
> hfs formatted disk, the lenght of the partition table depends on the version
> of the formatter :-(

Oh dear...
#define EXTREMELY_BROKEN
#include <broken-code-rant.h>

Fortunately, the 32 sector bit may not matter now - if we can implement
the following...

> But it possible to disable this mode with some special ATAPI commands, IIRC
> my brother told me that he send them to a linux developer a few months ago.

Provided we can do this *RELIABLY* (i.e. on ALL Zip drives), this could be
the best solution. Simply ensure that we always see the entire disk, and
so it will always be mounted as /dev/hda4 (assuming it is partitioned that
way).


James.


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