Hi,
On Thu, Jan 17, Oleg Drokin wrote:
> > > initrd, and thus at the bottom of the list. Strange enough SuSE compile
> > > MSDOS which hardly anyone needs at boot time into the kernel, but not
> > > reiserfs (admittedly, reiserfs takes up some memory, but then, it's a
> > FAT is needed in order to access some modules floppy disk at installation
> > time. Due to space reasons, our initrd also is using FAT format now.
> Why not use cramfs? It would generate smaller initrd, because it compresses files.
Yes, but the initrd is compressed anyway. Also, I need some filesystem for
accessing the floppy itself.
> > You need _some_ filesystem in the kernel. We chose the one that needs
> > least space and allows people to easily put additional modules onto some
> vfat 9872 0 (unused)
> fat 32000 0 [vfat]
> cramfs 37424 0 (unused)
> So it is 41k for vfat, or 37k for cramfs.
> crams if more space-efficient.
This is only the code. And the difference will be smaller after the kernel
has been compressed. We are using a special script for creating the FAT
floppy that allows for creating only one FAT which will save even more
space on the media. Look at those examples:
Mandelbrot:/tmp # df -T
Filesystem Type 1k-blocks Used Available Use% Mounted on
[...]
/tmp/fat vfat 1436 0 1436 0% /mnt2
/tmp/minix minix 1421 1 1420 1% /mnt
Mandelbrot:/tmp # l fat minix
-rw-r--r-- 1 root root 1474560 Jan 17 10:00 fat
-rw-r--r-- 1 root root 1474560 Jan 17 10:01 minix
> > floppy (some people have problems mounting an ext2/minix floppy under
> > Windows or DOS).
> There is no problems in loading vfat from e.g. initrd. And then to ask people to
>insert
If I have vfat in the initrd, I can as well have it in the kernel itself.
And then I can use fat even for the initrd itself. Why the need to have
some additional filesystem which will cost additional space?
> "additional driver disk" which would hold FAT fs on it.
And which filesystem to use for the "additional driver disk"?
> RedHat use minix for initrd, AFAIK. And minix fs support contains less code, too:
> minix 21616 0 (unused)
>
> > > Had they left MSDOS as a module, things would have worked out: 1. ext2
> > > in the kernel 2. initrd loads reiserfs 3. actual root (reiserfs) is
> > > mounted 4. only now, msdos.o becomes available.
> > And which format should we use for the modules disk and for the initrd? We
> I believe cramfs is much better than vfat for you.
Maybe, but we would need it in addition to some other filesystem then,
cause we need to access some floppy.
There are also additional historical reasons for using vfat: In the past,
we allowed for installation from some DOS disk (for people with
unsupported CD-ROM drives), so again we needed vfat support in the kernel
anyway.
> > used to have ext2 in the past. It caused problems for other people.
> Which problems?
No technical ones ;)
We are shipping floppies and quite some people called support and
complained that the disks are corrupt since they couldn't read them for
testing under DOS/Windows. This might sound funny to you, but if you are
shipping a huge number of boxes, this can become quite some problem.
Also, we can easily send them a replacement kernel/module and the users
easily can put them onto the disks without the need to already have a
second computer with linux running.
> Bye,
> Oleg
-o)
Hubert Mantel Goodbye, dots... /\\
_\_v
