Re: UFS not 64-bit clean?
Re: UFS not 64-bit clean?
- Subject: Re: UFS not 64-bit clean?
- From: Louis Gerbarg <email@hidden>
- Date: Tue, 11 Dec 2001 13:17:23 -0800
On Tuesday, December 11, 2001, at 11:34 AM, Chris Bednar wrote:
Depends on what you mean. It works correctly for me, at least
somewhere
between 7 and 8 gigs. It does not, however, appear to support files
that
are >4 gigs in size, at least on 32 bit machines.
That's what I mean (files > 4G). FreeBSD's UFS gets past
the 4G limit on 32-bit platforms, for example, and of course
Linux works fine that way with several filesystems on at least
x86 and ppc these days.
HFS+ and NFSv3 work fine on OSX too, as far as I can tell.
I glanced through the kernel code, and I see that LFS
support is possibly there, although it may require a
`#define LFS 1' kinda thing somewhere (a kernel-config
option?)
I went through all this with Linux back when I had time
to fool with things like arch/ppc/kernel/misc.S, but I'm hoping
to keep myself kinda clueless about building xnu as long as
I can ;)
As with all of the widely available source code bases for kernels I have
seen, it is not that bad to build, but it requires specific steps (some
of which may or may not be well documented).
Just for grins, though, I tried concatenating to the end of a 4 gig
file.
The append fails -silently-. AIEEEEE! Filing a bug.
Well, yes, that's really cute, too; I did something
like `rsh zorak cat RedHat7.2.iso > RedHat7.2.iso` and
it ran without complaint, but the file looked to be truncated
at 4G.
This is not about 64bit cleanliness (that really involves in memory
structure and call alignment). The max file size on UFS is either 2 or 4
gigs.
1) local
2) case sensitive
3) LFS-ready
I don't think you'd get much disagreement anyway. Keep in mind, this
tends to be a UNIX-y crowd. :-) I'm unclear why 64 bit file offsets
are
a requirement for this, though... or were you just wondering about
disks
over 4 gigs?
The three are more or less unrelated, except that I'd like
to have them together in one FS on OSX. As to disagreement,
I suppose the kernel list may be safe, but darwinos-users
is full of a big linguistic argument at the moment...
Um, if you really want to try to build LFS you can be adding the line
"option LFS" to the conf files in xnu. You really do not want to though.
The LFS code is stale (and may not be complete any more). It is based on
the old 4.4Lite LFS, which was not really production quality anyway (the
NetBSD folks seem to have been working on it in recent years, but we
never had that stuff). LFS probably has not been updated to UBC, may
never have worked int he first place, and is missing hooks for things
like the cleaner, which is not included in the standard source. In other
words, how much pain do you feel like enduring....
Don't get me wrong. I love the concept of an LFS. I think it is very
cool, and I think that in the future someone may do one that works well.
But in the present they leave a lot to be desired, and what you see in
our code is vestigial stuff from days long past.
Louis