From: James McMechan <james_mcmechan@ho...> - 2001-03-16 23:54:22
I was playing with uml-2.4.2-2um today and found some anomalies
first off I mounted hostfs in my uml readonly "mount -t hostfs /mnt /mnt"
It claimed it was read only but when I tried "touch /mnt/tmp/test1" I got
the expected read only error
But the file was created!. "rm /mnt/tmp/test1" removed it! once again with
the error about read only filesystem.
Is this expected behavior?
Why was I doing this, well I wanted to install some modules from my uml
PATH=$PATH:/mnt/sbin:/mnt/bin... went fine but when I did a "make
modules_install" from my uml kernel build
it put it in /lib/modules/2.4.2 and then depmod complained about missing
quickly fixed by a "ln -s /lib/modules/2.4.2 /lib/modules/2.4.2-2um ; make
Further I seem unable to get either serial console connected to a pty or the
virtual console xwindows to appear.
Possibily my RedHat 7.0 + 2.4.2 (with devfs turned on) is to blame? but I
did not see any obvious errors "error opening vc/0" or ttys/0 or cua/0 for
example. I copied the initfiles.tar over but still luck opening anything but
In other mucking about, the LFS stuff now commented out for hostfs worked
when I built it into the kernel and failed with modprobe errors about
missing lseek64 etc. I am assuming that this is another case of the uml side
module needing to link to the host libc, correct?
while dd does not have a conv=sparse option oddly enough cp does
"cp --sparse=always infile outfile" is supposed to remove all blocks of
zeros while copying creating a spare output file
for creating a new disk image "dd if=/dev/zero of=outfile bs=512 seek=$(( C
* H * S )) count=1" will create a nice huge file using only one data sector
on disk and the indirect blocks. This file can be then be "mkfs"ed like a
normal file, completely transparent. These optimization only work on smart
file systems, though, like ext2.