Re: why umsdos?

Matthew Wilcox (Matthew.Wilcox@genedata.com)
Sun, 8 Nov 1998 22:38:20 +0100


On Sun, Nov 08, 1998 at 03:31:21PM -0500, Anthony Barbachan 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).

> Ok let me see if I understand you correctly you want to replace UMSDOS,
> which works rather transparently and well, with an ext2 filesystem image on
> a FAT system?

Modulo the spin you just put on it, yes.

> Quicky reasons against this:
>
> 1. Increases risk to wipeing out the Linux system exponentially as by
> deletely one file accidently (the image file) on the DOS system would wipe
> out the Linux system.

Use ATTRIB under DOS to deal with this problem. And of course, your system
wouldn't be recoverable to the average newbie user (which is what his system
is designed for) if one were to delete (eg) C:\LINUX\LIB\LIBC.SO.

> 2. No speed improvement, most likely there would be a speed decrease.
> file system request -> UMSDOS -> FATFS -> drive
> vs.
> file system request -> EXT2 -> loop device driver -> FATFS -> drive

Show me the numbers, I'm not convinced.

> 3. No gain in feature except perhaps the cluster space problem on large
> drives (Not applicable if UMSDOS now works on FAT32 as I have hear)

you then don't need UMSDOS. And you don't need to write UNTFS.

> 4. Much wasted space as the image would be a set size (and probably not at
> 100% usage) while UMSDOS stores the files as files on the FAT filesystem
> resulting in the free space on the drive being share amoung both systems.

I don't think this is a problem if someone's evaluating Linux. If they
want to do more than evaluate Linux then they should partition anyway.

-- 
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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