[RC5] RE: [plans] distributed.net .plan update

Peter Cordes peter at llama.nslug.ns.ca
Mon Jun 18 04:46:48 EDT 2001


On Thu, Jun 14, 2001 at 11:20:49PM -0400, EnoJon wrote:
> 
> On Tuesday, June 12, 2001, at 02:28 AM, Peter Cordes wrote:
> 
> > On Mon, Jun 11, 2001 at 09:06:11PM -0400, Enojon wrote:
> >> I think he's referring to Linux (and all Unix unless 64-bit, even them
> >> sometimes) have
> >> a built in limit of 2GB filesize-meaning that you can't lseek past 2GB -
> >> -
> >> even if sequential
> >> data.
> >
> >  Solaris (for example, because I happen to have used it) has had 
> > large-file
> > extensions for a really long time.  That makes off_t a 64 bits integer
> > quantity, allowing seeks and memory mapping and anything else that deals
> > with file offset to happen anywhere out to 2^63, which is a _really_ long
> > way.  (Of course, even the functions that don't require you to specify an
> > offset have to keep track of where you are, so you can't read out past 2GB
> > without using LFS.)  The new interface consists of functions like open64 
> > and
> > read64.
> >
> >  From open(3) on my school's Solaris machine:
> >
> > USAGE
> >      The open() function has an explicit 64-bit equivalent.   See
> >      interface64(5).
> > 	
> >      Note that using open64() is equivalent to using open()  with
> >      O_LARGEFILE set in oflag.
> >
> >  The same interface exists on Linux now.  There have been patches that
> > provided it for a long time, and now it's in the kernel by default with
> > 2.4.x kernels and newer glibc (I think).
> >
> >> Too bad Linux/Unix doesn't provide for multi-volume units with
> >> "infinite" filesize
> >> like other operating systems.
> >
> >  2^64 is probably big enough for a really really long time.  If you're
> > talking about concatenating devices, then Linux supports that too.  (It's
> > called LVM == Logical Volume Management.)
> >
> >  Next time, avoid criticizing the technical details you don't know the
> > details of.  I bitch about windoze, but only about the stuff I know about
> > from having used it.  Otherwise, I'd end up saying stuff that wasn't true,
> > and make myself look silly.
> 
> Have you used LVM in a production environment?

 No.  I've only seen a few people mention using it, but they said they
were happy with it.  My main point was about large files, though.  Linux
2.4 kernels support large files out of the box.

cordes]~$ perl -w -e 'open( F, ">foo.out" ); seek(F, 2**34, 0 ); print F "hello\n";'
cordes]~$ ll foo.out
-rw-r--r--    1 peter    peter    17179869190 Jun 18 03:41 foo.out
cordes]~$ ll -h foo.out
-rw-r--r--    1 peter    peter         16G Jun 18 03:41 foo.out

 BTW, sorry for being snarky in my last message.

-- 
#define X(x,y) x##y
Peter Cordes ;  e-mail: X(peter at llama.nslug. , ns.ca)

"The gods confound the man who first found out how to distinguish the hours!
 Confound him, too, who in this place set up a sundial, to cut and hack
 my day so wretchedly into small pieces!" -- Plautus, 200 BCE
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