32 or 64 bit

[roland]

Hello,

Sorry for asking this question on this forum, but on the forum of K12ltsp  
nobody answers, and this is a general question.

I have a server with 2 x Xeon dual core processors.I installed Centos el5  
x86_64, then vmware server and now I like to install K12ltsp. On the  
download page from k12ltsp I have a choice of fedora 32 or 64 bit. What do  
I choose?

On the Fedora site I find x86_64 but not on K12ltsp. Do they mean by 64 =>  
X86_64?

Thanks and again sorry

[Jim Cornette]

roland wrote:
> Hello,
>
> Sorry for asking this question on this forum, but on the forum of 
> K12ltsp nobody answers, and this is a general question.
>
> I have a server with 2 x Xeon dual core processors.I installed Centos 
> el5 x86_64, then vmware server and now I like to install K12ltsp. On the 
> download page from k12ltsp I have a choice of fedora 32 or 64 bit. What 
> do I choose?
>
> On the Fedora site I find x86_64 but not on K12ltsp. Do they mean by 64 
> => X86_64?
>
> Thanks and again sorry

It is referencing the same thing. i386 is 32-bit and x86_64 i for 64-bit.

Jim

[Karl Larsen]

roland wrote:
> Hello,
>
> Sorry for asking this question on this forum, but on the forum of 
> K12ltsp nobody answers, and this is a general question.
>
> I have a server with 2 x Xeon dual core processors.I installed Centos 
> el5 x86_64, then vmware server and now I like to install K12ltsp. On the 
> download page from k12ltsp I have a choice of fedora 32 or 64 bit. What 
> do I choose?
>
> On the Fedora site I find x86_64 but not on K12ltsp. Do they mean by 64 
> => X86_64?
>
> Thanks and again sorry

On all the late Fedora versions you have a choice of 32 or 64 bit 
packages. If your CPU can work with 64 bit words your going to want to 
use the 64 bit Fedora for a server. This is because storing on a hard 
drive in 64 bit words is very much faster than doing it with 32 bit words.

[Chris Jones]

> On all the late Fedora versions you have a choice of 32 or 64 bit 
>
> packages. If your CPU can work with 64 bit words your going to want to 
> use the 64 bit Fedora for a server. This is because storing on a hard 
> drive in 64 bit words is very much faster than doing it with 32 bit words.

Erm, sorry Karl. Wrong again.

I've never heard any claims or evidence that 32/64 bit ODs have any 
impact on the harddisk access times. Someone please correct me if I'm 
wrong but this is not the reason people use 64 bit OSes.

As far as I am aware there are two reasons.

1. For technical reasons, a 64 bit build is normally a bit faster than a 
32 bit build, just due to compiler options. For normal desktop usages 
its unlikely you would notice a difference, but it can have one if you 
do heavy number crunching.

2. 64 bit OSes, have a larger memory address they can access. With 32bit 
OSes the largest amount of memory a single process can use is 4G I 
think. With 64bit this problem goes away. You may wonder why any single 
process may need that much ram... Its true not many will but some tasks, 
like large databases or image processing can get that high.

The downside to 64 bit is there are still a few bits and pieces missing. 
Some propriety drivers aren't yet available in 64 bit versions, or as 
most often comes up on this list, some common web plugins. This one can 
be worked around by running the 32 bit web browser (64 bit linux can run 
32 built binaries just fine, as long as you install enough 32 bit system 
libraries along side the 64 bit ones - often referred to as multilib'ing).

If it was me, and you can live without the few missing bits and bobs, I 
would go 64 bit if you hardware can do it.

Chris

[Alan Cox]

> I've never heard any claims or evidence that 32/64 bit ODs have any 
> impact on the harddisk access times. Someone please correct me if I'm 
> wrong but this is not the reason people use 64 bit OSes.

None at all on a typical system. Disk transfers are 16bit for ATA anyway
(32bit PIO as a special case we don't normally do but some day I should
add for the drives that do it), and DMA is used for all real disks today.
> As far as I am aware there are two reasons.
> For technical reasons, a 64 bit build is normally a bit faster than a
>
> 32 bit build, just due to compiler options. For normal desktop usages 
> its unlikely you would notice a difference, but it can have one if you 
> do heavy number crunching.

Its a bit more complicated. Generally speaking on systems user 64bit
binaries are slower than 32bit as they are bigger. PC (x86/x86-64) is a
bit different as x86-64 is very compact and also because it doubles the
number of usable registers in the instruction set which is a huge win. So
typically its about 10-20% faster. Desktop performance is usually bounded
by video performance (lots of opportunity for the X folks to improve
performance left) and most of the time the box is idle anyway so being
able to display an icon 20% faster isn't a big visible hit.
> 64 bit OSes, have a larger memory address they can access. With 32bit
>
> OSes the largest amount of memory a single process can use is 4G I 
> think. With 64bit this problem goes away. You may wonder why any single 
> process may need that much ram... Its true not many will but some tasks, 
> like large databases or image processing can get that high.

Even more importantly - the kernel can address more than 4GB at a time
without doing expensive memory management unit updates. That makes a very
big difference above 4GB and quite a big one above 1GB RAM (the kernel
normally has 1GB of RAM and 3GB available for the user application - more
requires switching between the user and physical memory view which is not
cheap)

[Rick Stevens]

On Fri, 2007-08-03 at 14:04 +0200, roland wrote:
> Hello,
>
> Sorry for asking this question on this forum, but on the forum of K12ltsp  
> nobody answers, and this is a general question.
>
> I have a server with 2 x Xeon dual core processors.I installed Centos el5  
> x86_64, then vmware server and now I like to install K12ltsp. On the  
> download page from k12ltsp I have a choice of fedora 32 or 64 bit. What do  
> I choose?
>
> On the Fedora site I find x86_64 but not on K12ltsp. Do they mean by 64 =>  
> X86_64?

i386, i486, i568 and i686 are all 32-bit systems.  x86_64 refers to
any 64-bit thing running on an Intel 64-bit processor (Xeon, Centrino
Duo-core, etc. or any that supports the E64T extensions) or AMD 64-bit
processors (Athlon X2, Opteron, etc.).  Note also that the 64-bit
machines above will happily run the 32-bit operating system as well.
The reverse is NOT true...the 32-bit machines can NOT run the 64-bit
operating system.

If you want maximum compatibility, run the 32-bit stuff regardless of
which processor you have.  There are still gaps in some third party
software support of 64-bit (e.g. there's no 64-bit Flash player).  You
really only see a big performance improvement using 64-bit stuff when
the task is compute-bound.
----------------------------------------------------------------------
- Rick Stevens, Principal Engineer             [e-mail] -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
-  BASIC is the Computer Science version of `Scientific Creationism' -
----------------------------------------------------------------------

32 or 64 bit *** THANKS TO EVERYBODY ***

[roland]

On Fri, 03 Aug 2007 19:26:38 +0200, Rick Stevens   
wrote:
> On Fri, 2007-08-03 at 14:04 +0200, roland wrote:
> > Hello,
> >
> > Sorry for asking this question on this forum, but on the forum of  
> > K12ltsp
> > nobody answers, and this is a general question.
> >
> > I have a server with 2 x Xeon dual core processors.I installed Centos  
> > el5
> > x86_64, then vmware server and now I like to install K12ltsp. On the
> > download page from k12ltsp I have a choice of fedora 32 or 64 bit. What  
> > do
> > I choose?
> >
> > On the Fedora site I find x86_64 but not on K12ltsp. Do they mean by 64  
> > =>
> > X86_64?
>
> i386, i486, i568 and i686 are all 32-bit systems.  x86_64 refers to
> any 64-bit thing running on an Intel 64-bit processor (Xeon, Centrino
> Duo-core, etc. or any that supports the E64T extensions) or AMD 64-bit
> processors (Athlon X2, Opteron, etc.).  Note also that the 64-bit
> machines above will happily run the 32-bit operating system as well.
> The reverse is NOT true...the 32-bit machines can NOT run the 64-bit
> operating system.
>
> If you want maximum compatibility, run the 32-bit stuff regardless of
> which processor you have.  There are still gaps in some third party
> software support of 64-bit (e.g. there's no 64-bit Flash player).  You
> really only see a big performance improvement using 64-bit stuff when
> the task is compute-bound.
> Rick Stevens, Principal Engineer             [e-mail] -
> VitalStream, Inc.                       http://www.vitalstream.com -
>                                                                -
> BASIC is the Computer Science version of `Scientific Creationism' -

Thank you, Rick, and off course the others also.

As always I admire you, Rick, for an answer only you can give,  
professional and extensiv compact. :-)

Is wish you all a nice and sunny sunday.

32 or 64 bit *** THANKS TO EVERYBODY ***

[Rick Stevens]

On Sun, 2007-08-05 at 09:43 +0200, roland wrote:
> On Fri, 03 Aug 2007 19:26:38 +0200, Rick Stevens   
> wrote:
> > On Fri, 2007-08-03 at 14:04 +0200, roland wrote:
> > > Hello,
> > >
> > > Sorry for asking this question on this forum, but on the forum of  
> > > K12ltsp
> > > nobody answers, and this is a general question.
> > >
> > > I have a server with 2 x Xeon dual core processors.I installed Centos  
> > > el5
> > > x86_64, then vmware server and now I like to install K12ltsp. On the
> > > download page from k12ltsp I have a choice of fedora 32 or 64 bit. What  
> > > do
> > > I choose?
> > >
> > > On the Fedora site I find x86_64 but not on K12ltsp. Do they mean by 64  
> > > =>
> > > X86_64?
> >
> > i386, i486, i568 and i686 are all 32-bit systems.  x86_64 refers to
> > any 64-bit thing running on an Intel 64-bit processor (Xeon, Centrino
> > Duo-core, etc. or any that supports the E64T extensions) or AMD 64-bit
> > processors (Athlon X2, Opteron, etc.).  Note also that the 64-bit
> > machines above will happily run the 32-bit operating system as well.
> > The reverse is NOT true...the 32-bit machines can NOT run the 64-bit
> > operating system.
> >
> > If you want maximum compatibility, run the 32-bit stuff regardless of
> > which processor you have.  There are still gaps in some third party
> > software support of 64-bit (e.g. there's no 64-bit Flash player).  You
> > really only see a big performance improvement using 64-bit stuff when
> > the task is compute-bound.
> > Rick Stevens, Principal Engineer             [e-mail] -
> > VitalStream, Inc.                       http://www.vitalstream.com -
> >                                                                -
> > BASIC is the Computer Science version of `Scientific Creationism' -
>
> Thank you, Rick, and off course the others also.
>
> As always I admire you, Rick, for an answer only you can give,  
> professional and extensiv compact. :-)

[blush!] Thank you, kind sir!  We all do our best. :-D
> Is wish you all a nice and sunny sunday.

Heheheh!  We've been moving a datacenter all night, so I've been here
chained to my desk for about 36 hours now.  Hey, the sun's coming up!
...again!

----------------------------------------------------------------------
- Rick Stevens, Principal Engineer             [e-mail] -
- CDN Systems, Internap, Inc.                http://www.internap.com -
-                                                                    -
-         "OK, so you're a Ph.D. Just don't TOUCH anything!"         -
----------------------------------------------------------------------