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

Peter Cordes peter at llama.nslug.ns.ca
Tue Jun 12 04:28:03 EDT 2001


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.

-- 
#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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