Hi!
As a "newbie" to kernel building, I would like to suggest that it may be
helpful
to your readers to publish a how-to about adding 48-bit disk address
support - for example, to support the new Maxtor 160 GB ATA133 drives.
The online literature on this topic is pretty obscure.
In particular, I started with kernel 2.4.9 and discovered:
1) fdisk, cfdisk and sfdisk all think the drive has 16709 logical cylinders
(each of 16065*512) bytes. Should be 19929.
2) cfdisk lets your override the size (-c 19929), so I did so. mke2fs
also required
a command line argument to override the default disk size.
Everything looked fine
until I started getting filesystem errors and found that the
partitions on the
disk were trashed.. Bottom line - mainline linux ATA drivers
totally mess up
without warning! This appears to be due to a 28-bit disk address
limitation (137 GB).
3) Found a note that the Alan Cox 2.4.18-pre7-ac3 kernel patch supports
48-bit
addressing. However, I did not find anywhere an indication of what
kernel
this patch should be applied to. Through trial and error I
discovered that
the sequence:
2.4.17
2.4.18-pre7 (in the "testing"
directory at linux.org)
2.4.18-pre7-ac3 (in the people/alan
directory at linux.org)
works fine. Don't try to add any of the other 2.4.18-preXX
patches as they
will not work correctly to get to the goal.
4) RedHat has some other peculiarities:
A) Run /sbin/installkernel 2.4.18-pre7-ac3 bzImage
../../../System.map from the boot
directory under "arch" after you finish building the
kernel.
If you are using lilo, this should work fine. If you
are using
grub, installkernel will complain about the lilo
configuration - ignore the error.
The main thing is that this copies the kernel and the
System.map files to /boot,
renames them, and sets up links appropriately.
B) If you want the initrd file, go into /boot and type
mkinitrd initrd-2.4.18-pre7-ac3.img
2.4.18-pre7-ac3
C) Also copy the kernel.h file from include/linux to /boot,
rename it to
kernel.h-2.4.18-pre7-ac3
and create a soft link from kernel.h to this file.
C) If you are using grub, edit the /boot/grub/grub.conf
file. Follow the pattern of the
existing entries.
D) IF ANYONE CAN TELL ME HOW TO SET UP THE MODULE-INFO file
in RedHat's /boot directory, PLEASE DO SO! In fact,
there does not appear to
be any documentation on the RedHat website about what
these files are for.
4) With the patched Linux kernel, fdisk now shows the correct disk
size, mke2fs sees
the correct size without manually overrides, and Linux appears
to be happy with the disk!
A caution: cfdisk now DOES NOT WORK! (I am not sure who
maintains cfdisk
but it needs some attention.)
4) Moral: it really would be helpful if kernel patches documented
what version/
patch they are patching. Maybe a master table showing the
progression would be
helpful
5) Bottom line: go get a 160 GB drive and enjoy the space! Just be
sure to use the Alan Cox
kernel patch!!!
Jim Schatzman
--
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