Re: Msdos name alias patch for 2.1.48

Richard B. Johnson (root@analogic.com)
Fri, 8 Aug 1997 09:03:42 -0400 (EDT)


On Fri, 8 Aug 1997, Marcin Dalecki wrote:

> On Thu, 7 Aug 1997, Linus Torvalds wrote:
>
> > What sort of case-insensitivity do various filesystems currently support?
> > Are we talking A-Z only, Latin1, or what? I guess we don't really need to
> > worry about what could theoretically be the worst case, but what MS-DOS,
> > NT, OS/2 etc actually do right now..
> >
> > Linus
> >
> Sorry. MS-DOS ** IS NOT ** case insensitive. It is ONLY
> command.com.... So Linus: plase don't worry at all. If somebody using an
> MS-DOS filesystem went into trouble by writing wrong case filenames onto it
> NOTHING bad would happen to DOS. The other way around it's anyway an non
> issue.
>
You can create, read, write, delete file names that have any characters
except 0x00 and 0xe5 under MS-DOS. If 0xe5 isn't the first character, you
can use that too. The command interpreter will not like strange file names
which is the reason why some programs use them (user's can't delete them
without writting a program to delete them). Note that there is really
no '.' in a MS-DOS file-name. It is not in the directory entry. Therefore,
the logic to use a '.' is simple. If the real file-name contains anything
other than spaces as its last three characters, you add a '.' before
outputting those characters. Leading and trailing spaces are cut.

Name Entry DOS Display Unix Display

'CONTIGUOUS' -> CONTIGU.OUS contigu.ous
' S' -> .S .s
'CONTIGU ' -> CONTIGU contigu
' OUS' -> .OUS .ous

BYW, one can create a "*.*" file-name under MS-DOS, just like unix. It's
directory entry would be:
'* * '

Cheers,
DJ
Richard B. Johnson
Analogic Corporation
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