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SubjectRe: ATAPI Zip problems
Hi all.

>> Incidentally, when I put a Zip-100 disk in the drive,
>> the two values are approximately 250M and approximately
>> 100M resspectively, and when I put a Zip-250 in, they
>> are DIFFERENT numbers, but both approx 250M.

I've now got that system back online, so I've enclosed the
relevant extracts from /var/log/messages.

> People tell me they see "The drive reports both 250609664
> and 250640384 bytes as its capacity" But this just means
> that it has capacity 250640384.

> (If one computes a geometry from this, and takes sector
> size 512, and 64 heads and 32 sectors/track the number of
> cylinders will become 250640384/(512*64*32) = 239.

Let's see...

Q> # echo 3k 250640384 512/64/32/p | dc
Q> 239.029
Q> #

Slightly larger, but I follow your meaning...

> If one then again multiplies 512*64*32*239 the result is
> 250609664.

Nodz.

> In other words, the kernel message is a bug, there is
> usually some rounding when computer some fake number of
> cylinders, and the resulting CHS capacity will be a little
> bit smaller than the actual one.) So, in ide-floppy.c this
> message is entirely superfluous, and the code throws away
> 30 kB of floppy space.

Nodz.

> But I would like to see what you get in the 100M case.

See the enclosed.

It looks like the drive is always reporting the same capacity
independant of what disk has been inserted, which sounds like
a hardware bug that the kernel needs to be aware of...

Best wishes from Riley.

* Copyright (C) 2000, Memory Alpha Systems.
* All rights and wrongs reserved.

+----------------------------------------------------------------------+
| There is something frustrating about the quality and speed of Linux |
| development, ie., the quality is too high and the speed is too high, |
| in other words, I can implement this XXXX feature, but I bet someone |
| else has already done so and is just about to release their patch. |
+----------------------------------------------------------------------+
* http://www.memalpha.cx/Linux/Kernel/
Insert 100M ZipDisk into Zip-250 drive. On mount followed by umount, the
following messages appear:

kernel: hdb: 98304kB, 196608 blocks, 512 sector size
kernel: hdb: 244736kB, 239/64/32 CHS, 4096 kBps, 512 sector size, 2941 rpm
kernel: hdb: The drive reports both 250609664 and 100663296 bytes as its capacity
kernel: hdb: hdb4
kernel: hdb: 98304kB, 96/64/32 CHS, 4096 kBps, 512 sector size, 2941 rpm
kernel: hdb: hdb4
kernel: hdb: hdb4

Replace with 250M ZipDisk. On mount followed by umount, the following
messages appear:

kernel: hdb: 244766kB, 489532 blocks, 512 sector size
kernel: hdb: 244736kB, 239/64/32 CHS, 4096 kBps, 512 sector size, 2941 rpm
kernel: hdb: The drive reports both 250609664 and 250640384 bytes as its capacity
kernel: hdb: hdb4
kernel: hdb: The drive reports both 250609664 and 250640384 bytes as its capacity
kernel: hdb: hdb4
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