Where did lib64 directories come from

[Shams]

Hi,

I noticed that Fedora has both /usr/lib and /usr/lib64

Is this only on Fedora or standard across many Linux distros?
Why is this needed, I mean why not just have /usr/lib?

Thanks
Shams

[Steve Siegfried]

Shams wrote:
> Hi,
>
> I noticed that Fedora has both /usr/lib and /usr/lib64
>
> Is this only on Fedora or standard across many Linux distros?
> Why is this needed, I mean why not just have /usr/lib?
>
> Thanks
> Shams

Umm... because you've got a 64-bit CPU that supports both ia32 and
either ia64 or x86-64?

This is pretty standard across most 64-bit capable distributions.

[Shams]

Hi,

Thanks for the info.

Yes I have a 64-bit cpu but  technically why is this needed, can it be just 
solved
with having all the 64-bit libs in /usr/lib?

Does this mean that if I have a 64-bit cpu that is not capable of supporting 
ia32
then only /usr/lib will exist?

Thanks
Shams

[Shams]

Also I've installed Fedora 7 x86-64 if relevant.

Thanks
Shams

[Steve Siegfried]

Shams wrote:
> Also I've installed Fedora 7 x86-64 if relevant.
>
> Thanks
> Shams

Yeah, it is relevant.  So I assume that running "cat /proc/cpuinfo"
says you've got some sort of X86-64 chip, right?

-S

[Shams]

Hi,

The chip is an Intel Pentium D Dual Core 64-bit.

Thanks
Shams

[Steve Siegfried]

Shams wrote:
> Hi,
>
> Thanks for the info.
>
> Yes I have a 64-bit cpu but  technically why is this needed, can it be just 
> solved
> with having all the 64-bit libs in /usr/lib?
>
> Does this mean that if I have a 64-bit cpu that is not capable of supporting 
> ia32
> then only /usr/lib will exist?
>
> Thanks
> Shams
>
> --
>
> "Steve Siegfried"  wrote in message 
> news:[e-mail]...
> > Shams wrote:
> > > Hi,
> > >
> > > I noticed that Fedora has both /usr/lib and /usr/lib64
> > >
> > > Is this only on Fedora or standard across many Linux distros?
> > > Why is this needed, I mean why not just have /usr/lib?
> > >
> > > Thanks
> > > Shams
> >
> > Umm... because you've got a 64-bit CPU that supports both ia32 and
> > either ia64 or x86-64?
> >
> > This is pretty standard across most 64-bit capable distributions.

With the /usr/lib64 stuff, you can build/install 64 bit binaries and expect
them to run.

With the /usr/lib stuff, you can build/install 32 bit binaries and expect
them to run, too.

So basically, you have a CPU that can run either flavor of binary; thus
the two flavors of libraries to support that.

Is there any real advantage to using either 32 bit or 64 bit binaries
on a 64 bit CPU?   For most programs, not really, mostly since very few
folks have anywhere near 32 bits worth (let alone more)  of real memory.
Yeah... you can write larger programs with 64 bit binaries, but without
the real memory to run 'em in, most large programs (even 32 bit ones)
grow right up to the point were they exceed available memory, start
swapping and then sloooow waaaaaaaaaaay dowwwwwwwwnnnnnnnnnnnnnnnnnn.

And yes, if you had a 64 bit CPU that didn't support a 32 bit mode, then
you'd probably only have /usr/lib.  However, there aren't that many pure
64 bit chips out there (leastways that most folks can afford).

-S

[Langdon Stevenson]

<snip>
> Is there any real advantage to using either 32 bit or 64 bit binaries
> on a 64 bit CPU?   For most programs, not really, mostly since very few
> folks have anywhere near 32 bits worth (let alone more)  of real memory.
> Yeah... you can write larger programs with 64 bit binaries, but without
> the real memory to run 'em in, most large programs (even 32 bit ones)
> grow right up to the point were they exceed available memory, start
> swapping and then sloooow waaaaaaaaaaay dowwwwwwwwnnnnnnnnnnnnnnnnnn.

Having just switched from a 32 bit kernel and apps to a 64 bit kernel 
and apps on the same hardware (Core 2 Duo E6600) that the machine seemed 
a bit more responsive than previously.  I wasn't looking for an 
improvement, just noticed that it was all a bit "snappier" than before. 
  Apps load a little faster, machine seems a little more responsive.

This was totally unexpected, but a nice surprise.

Regards,
Langdon

[Shams]

Hi,

I also experiance a dramatic speed improvement in bootup and general
usage in Fedora 7 compared to Fedora 6.

Thanks
Shams

[Ingemar Nilsson]

[e-mail] (Steve Siegfried) writes:
> Is there any real advantage to using either 32 bit or 64 bit binaries
> on a 64 bit CPU?   For most programs, not really, mostly since very few
> folks have anywhere near 32 bits worth (let alone more)  of real memory.

More memory isn't the only advantage of using x86-64-compiled binaries over
using i386-compiled binaries. x86-64 also has twice as many registers, both
general-purpose and XMM (SSE), as i386. This means that the program can
keep more variables in registers at once, without having to swap them in
and out of memory.

Regards
Ingemar

In article , Shams  wrote:
> Yes I have a 64-bit cpu but technically why is this needed, can
> it be just solved with having all the 64-bit libs in /usr/lib?

Not if you want to be able to run 32 bit programs that use
those libraries. There's quite a bit of software that does
not have 64 bit versions.

--
http://www.spinics.net/lists/

[Steven Ringwald]

On 6/7/07, Shams  wrote:
> Hi,
>
> I noticed that Fedora has both /usr/lib and /usr/lib64
>
> Is this only on Fedora or standard across many Linux distros?
> Why is this needed, I mean why not just have /usr/lib?

Sounds like you installed the 64 bit version of Fedora. This is standard, as
64 and 32 bit binaries need their own versions of the shared libraries.
Windows XP 64 does something similar. There is a "Program Files" and
"Program Files (x68)" directories.

Steve