[syslinux] Possible memdisk issue
Alexander Perlis
aperlis at math.lsu.edu
Wed Jul 9 13:54:42 PDT 2014
On Tue, 08 Jul 2014 15:54, H. Peter Anvin wrote:
>
>On 07/08/2014 11:26 AM, Ady wrote:
>>
>> It's interesting that you ask this, because every document related to
>> newmkfloppyimg.sh specifically recommends adding:
>> floppy c=$CYLINDERS s=$SECTORS h=$HEADS
>> to the MEMDISK arguments.
>>
>
>It would be important for floppies to know if the geometry that MEMDISK
>guesses is the one that you actually intended. This will be in the
>information that was snipped out.
Ah, this might explain things although I don't know what is meant by
"intended". First, to clarify, newmkfloppyimg calls mkdosfs 3.0.12, and
grabs H/S from the output and then computes C. For all the sizes I've
tried, newmkfloppyimg always tells me H=64 S=32 and then C is the
approximately the number of MB. And MEMDISK auto-determines those exact
same numbers. But if I manually call mkdosfs there's a lot more output,
most of it ignored by newmkfloppyimg. In particular, the output for
8203K and 8204K is different:
mkdosfs -I -v -C test8203 8203
mkdosfs 3.0.12 (29 Oct 2011)
test8203 has 64 heads and 32 sectors per track,
logical sector size is 512,
using 0xf8 media descriptor, with 16406 sectors;
file system has 2 12-bit FATs and 8 sectors per cluster.
FAT size is 8 sectors, and provides 2043 clusters.
There are 8 reserved sectors.
mkdosfs -I -v -C test8204 8204
mkdosfs 3.0.12 (29 Oct 2011)
test8204 has 64 heads and 32 sectors per track,
logical sector size is 512,
using 0xf8 media descriptor, with 16408 sectors;
file system has 2 16-bit FATs and 4 sectors per cluster.
FAT size is 16 sectors, and provides 4085 clusters.
There are 4 reserved sectors.
In both cases, newmkfloppyimg says to use "C/H/S=8/64/32", and that's
what MEMDISK is using. So I believe I'm "intending" those values. Or are
they not correct?
Alex
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