[K12OSN] AMD64 K12LTSP

[Angus Carr]

David Trask wrote:

>"Support list for opensource software in schools." <k12osn at redhat.com> on
>Tuesday, January 4, 2005 at 11:35 AM +0000 wrote:
>  
>
>>Over vacation my laptop died. I bought a shiny new HP Pavilion zv5000
>>with an amd64 cpu in it. I should have some sort of K12LTSP/64 support
>>in the near future...
>>
>>-Eric
>>    
>>
>
>Eric...pardon my ignorance, but what are the primary benefits of running
>64 bit as opposed to 32 bit in a K12LTSP environment?  Really curious as I
>might budget for a new server....
>
>David N. Trask
>Technology Teacher/Coordinator
>Vassalboro Community School
>dtrask at vcs.u52.k12.me.us
>(207)923-3100
>
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>
>  
>
Pardon me tossing my 2 cents worth in, but...
The primary reason I have selected the amd64 chip over the 32bit version 
is the speed / temperature tradeoff. The 64 bit architecture has more 
registers and fewer stages in the instruction pipeline, so when code is 
compiled in that form, it can run more efficiently. This can be seen on 
benchmarks under Linux, where the 64 bit OS can be used.

Becasue the chip is more efficient at processing instructions, they have 
marketted them as "3800+" or whatever, to represent the equivalent 
pentium4 speed. In fact, the processor is clocked much lower. The 3800+ 
unit is clocked at 2.4 GHz.

Another architectural thing on the amd chips is that they clock 
themselves lower when not in use. This cuts the effective operating 
temperature. If you have to sit beside the server, it is quieter. That, 
and energy savings.

The last, and probably most important, thing is that the 64 bit chips 
can access far more memory than the 32 bit chips. 32 bit chips are 
limited to 4GB of RAM visible to the processor at a time (remember 
bank-switching?). The 64 bit chip can address much more memory at a time.

The 64 bit chip can still run 32-bit binaries, which is good for running 
32-bit versions of the OS (whichever one you use). In fact, you can mix 
32-bit binaries and 64-bit binaries, as long as you have library support 
and are running the 64-bit OS.

The net result is that the price/performance equation is in for the AMD 
64 chips right now, although that may change. An equivalent Pentium chip 
is probably just as good for most of us, until the RAM requirement ramps 
up too high.

Angus Carr.