Re: why umsdos?

Matthew Wilcox (Matthew.Wilcox@genedata.com)
Sun, 8 Nov 1998 17:52:43 +0100


On Sun, Nov 08, 1998 at 04:17:40PM +0100, Horvath Akos wrote:
> On Sun, 8 Nov 1998, Matthew Wilcox wrote:
> > I don't like umsdos personally. Have you considered using a file on the
> > msdos filesystem with an ext2 filesystem on it instead? I have a machine
> > with its root filesystem mounted on /dev/loop0. A little playing with
> > initrd makes this quite easy. This means you have no need for a untfs
> > (and in my case, no need for a uadfs).
>
> Five reasons to not to use this:
> - You can not resize an ext2fs image - repartitioning is better, because
> FIPS, presizer or Partition Magic can resize msdos partitions

PartitionMagic can now resize ext2 partitions. The code to do this was
written by tytso under contract. There will (after a certain amount of
time) be a standalone ext2resizer. You cannot resize files containing
ext2 partitions now, I understand that. However you don't necessarily
need to. If someone's `just trying it out', they will almost certainly
not need to resize their partition. If they really do, they can be
introduced to the joys of multiple partitions and a single filesystem
hierarchy.

> - You can not read az ext2fs image from dos

There are several tools that do this. There's even a VxD for Windows 95.

> - It will be slow (ok, umsdos is slow too)

Then this is not an argument.

> - A newbie will never be able to set up a looproot distribution

I don't understand what point you're trying to make there. There should
not be any user-visible difference between setting up a looproot and an
umsdosroot distribution.

> - Looproot is problematic and untested (for example it does not work in
> vfat but works on an msdos partition)

Why does it not work on vfat? All it does is use the filesystem bmap()
method. Since vfat's bmap method is in fact the fat bmap method,
I don't think this is possible. Have you tried it?

> I think, a general ums-like pseudo-ext2-fs over not only umsdos, but all
> non unix-compatible fs were very good and useful for the linux community.

I disagree. It would be a lot of work for very little gain. Different
filesystems differ so much that it would be almost impossible, and
even if you did, it would always be a kludge of limited usefulness.
Compared to the loop device which we already have with its multiple uses,
I really don't see the point.

-- 
Matthew Wilcox <willy@bofh.ai>
"I decry the current tendency to seek patents on algorithms.  There are
better ways to earn a living than to prevent other people from making use of
one's contributions to computer science."  -- Donald E. Knuth, TAoCP vol 3

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