Ramdisk size

[linux-os \(Dick Johnson\)]

Hello,
On an embedded system, I use two ramdisks. They are both
16 megabytes in size. I can create them interactively in
the normal way with mke2fs. However, when the system is
booted using isolinux, the RAM disks become corrupted.
Apparently isolinux.cfg's ramdisk_size (not documented,
only referenced, BYW) is not in 1k increments. That value
seems to affect all ramdisks, not just the `initrd` one.
I can prevent corruption by setting the value to 200000
(way too much). However I won't have any RAM left for
applications! I need to know how much RAM a ramdisk of
16386 bytes takes, and how to set it in isolinux.cfg
(what the multiplier is).

The file-system mounts properly, but a write of one byte
causes the following error:

EXT-FS error (Device ram2);
ext2_new_block: Allocation block in system zone block = 129

e2fsck reports:
 	+(129--256) + (8321--8448)
 	block bitmap differences

It's difficult to find out what is being corrupted because
`mke2fs` never creates the same thing twice!! There is some
time-stuff in it, therefore I can't find out what actually
is getting trashed. Currently, it doesn't look like anything
at the ends of the raw disk get trashed. Instead, it looks
like the ramdisk size when booted using isolinux is simply
not the same size as when the ramdisk contents were created.

Cheers,
Dick Johnson
Penguin : Linux version 2.6.16.24 on an i686 machine (5592.65 BogoMips).
New book: http://www.AbominableFirebug.com/
_


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