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From: guy%gorodish@Sun.COM (Guy Harris)
Newsgroups: comp.unix.questions
Subject: Re: (Probably dumb) SysVR3 questions
Message-ID: <25420@sun.uucp>
Date: Wed, 12-Aug-87 03:37:41 EDT
Article-I.D.: sun.25420
Posted: Wed Aug 12 03:37:41 1987
Date-Received: Fri, 14-Aug-87 04:20:57 EDT
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> > The 14-character file-name limit is killing us; is it extendable
> > (redefine something, somewhere?) by remaking the kernel?
> 
> No, you would also have to remake many of the standard commands.
> (ls, etc...)
> 
> You would then run into problems with anything else that thinks
> there is a 14 character size (SGS, uucp, cpio, etc....)

"cpio" thinks there is a 14 character size?  Gee, that's news to me.  Sun has
supplied "cpio" with its systems for quite a while, and has had file systems
without a 14-character file size limit for at least as long.  The only changes
made to "cpio" (until a lot of real grot was cleaned up recently) had nothing
to do with the directory format; "cpio" doesn't even know what directories look
like!

As for "uucp", well, err, umm, there's this #define constant in the Honey
Danber source to S5R3 called "BSD4_2"; presumably it wasn't just stuck in there
for decoration.  It may not *use* more than 14 characters of the file name, but
it uses the directory library so it should be capable of surviving changes to
directory names.

COFF, unfortunately, thinks file names are limited to 14 characters (I presume
this is the source of SGS's problem), but that's just a botch.  You could stick
longer file names in the string table, and just have first 4 bytes of the
filename auxiliary entry be zero and the next 4 be a string table index.

You missed the *real* killer, though; if he just redefined DIRSIZE to something
other than 14, and recompiled the kernel, every single one of the file systems
on his disks would be totally unusable by that kernel!

DIRSIZE is in the "fundamental constants of the implementation-- cannot be
changed easily" section of <sys/param.h>, with good reason.  (Other items in
that section, such as CLKTICK ("microseconds in a clock tick") and CDLIMIT
("default max write address", i.e. default "ulimit"), don't belong there at
all, of course.  The latter should, of course, be changed to 0x7fffffff or some
other flavor of MAXLONG.)
	Guy Harris
	{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
	guy@sun.com