Re: looped root filesystem

jfm2@club-internet.fr
15 Aug 1997 09:04:45 -0000


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Date: Thu, 14 Aug 1997 14:47:41 -0400 (EDT)
From: "Daniel G. Linder" <dlinder@zeus.webcentric.net>
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"Richard Taylor" <rtaylor@perkins-engines.com> wrote:
> Miguel A.L. Paraz <map@iphil.net> wrote:
> >Is there any work being done, or is it practical at all, to
> >use a loopback device for root? I'm thinking of making it easier
> >to run Linux part-time on Windows machines; we create an ext2
> >filesystem on the FAT/VFAT system, even make it contiguous, then
> >use that as root.
>
> How about the using a UMSDOS filesystem for root? Would seem
> to cover your requirements, no? I remember mini distributions using
> this, i.e. unzip into your FAT fs and use loadlin to boot.
>
> Any use, or have I been working too hard today?
>
> cheers,
>
> Rich.

One of the reasons to use a looped filesystem as opposed to the UMSDOS
filesystem is space. Since UNIX/Linux use small files all over the place,
those files take up 32K on a large 1GB DOS partition. If you use the
looped filesystem (which is really a large, plain file to DOS), the Linux
ext2 filesystem handles these small files much better and DOS only sees
one large 200MB file.

The only downfall of this is that the root filesystem is a set file size
and I don't know of any Linux utilities that can change it's size as free
space requirements change. Anyone familiar with the looped FS able to
write up a shrink/grow program?

Dan

--
Daniel Linder W:(402) 393-3997 C:(402) 490-1673 P:(402) 579-1615
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Make an UMSDOS file system for / and loopbacks for /usr, /home and
/var. The only problem is /dev: it has 1300 files so it will probably
use 40 megs under DOS (perhaps not, for DOS they are empty files). If
you notice than special files use 32K on UMSDOS then you coould have a
stripped down /dev for booting on UMSDOS and you mount a loopback file
on /dev.

-- 
			Jean Francois Martinez

==================== The Linux. Use the Linux, Luke! =======================