Olaf Matthes olaf.matthes at gmx.de
Sun Nov 16 18:08:37 CET 2003

derek holzer schrieb:
> these are some pretty interesting "benchmarks", espc in regards to the
> performance of your SGI! it inspired me to do some late night shopping
> for old SGI machines here in holland. seems you can pick up a 200 MHz
> Octane, or a dual 150 MHz, for something like EUR 350-400.

I got my Octane for 500,- Euro. - I just needed a machine for sound
installations that I wouldn't miss at home. Trying to find a cheap
solution I discovered the low prices for 'old' SGIs. Since these
machines have ADAT IO build in you even safe the costs for a Hammerfall
or similar card!

> can you use linux, or only IRIX? if linux is runnable, which distro? 

I haven't tried that. There should be at least one Linux distro out
there for SGI machines, but I don't knwo anything special. IRIX works so
I saw no need to install Linux. And I guess IRIX is better optimized for
these machines.

> how is general audio performance on this machine? i was quite amazed at
> the cpu speed-to-pd performance ratio. 

Me too! I didn't expect to find such a great difference on the platforms
I tested. I'm currently toying around with low latencies on the Octane
and 5 ms seem to be quite possible.

> that you use pd 0.36 over 0.37 for reasons of the Portaudio... are other
> problems you have noticed regarding software incompatibilities?

Soeren Bovbjerg spent some wotk on getting Pd 0.36 to run on IRIX and he
also provided working binaries. That's why I started with 0.36. Sound
input was not working so I fixed it and recompiled the whole stuff with
GCC to avoid the MIPSpro compiler one would need to buy otherwise.
I have to admit that I haven't tried 0.37. I guess it won't even compile
(or will it, Miller?). The Portaudio thing just scared me!

> if you are buying an older SGI, like one of the first series O2s or
> Octanes, how is support for more modern PCI cards, like soundcards or
> firewire cards?

Well, you have to buy the few cards that are supported in these
machines. They do exist (soundcards at least, not shure about firewire),
but expect to pay quite a lot of money.

> last question: are SGIs more efficient with RAM? it seems like all the
> machines i saw were pretty low in this dept [maybe that's why there are
> cheap!]

SGIs don't use a bus system where all devices have to share one physical
connection. They instead use a 'crossbar switch' with 1.6Gbit/s
throughput. That is, different parts can exchange data directly without
blocking a bus system. I guess thats the secret for the speed. You just
can't compare them with 'ordinary' PC architectures.

Regarding my 'benchmarks', a test on a PC running Linux would be nice.
Attached is a patch using clone
(http://www.akustische-kunst.org/puredata/clone/) to test your machine.
Just increase the number of abstractions and hit the bang. Listen to the
sound and remember the number of abstractions when the sound get's ugly.
That's what I did on all my machines to compare the performance. 

-------------- next part --------------
#N canvas 435 76 667 576 12;
#X floatatom 61 216 5 0 0 0 - - -;
#X obj 241 513 dac~;
#X obj 42 443 clone test-abs 2;
#X obj 241 485 osc~ 200;
#X text 319 485 reference sound to listen to;
#X text 111 216 number of osc~ objects to load;
#X obj 42 298 int;
#X obj 71 252 bng 15 250 50 0 empty empty empty 0 -6 0 8 -262144 -1
#X text 98 252 hit bang to load;
#X msg 42 373 reload test-abs \$1;
#X connect 0 0 6 1;
#X connect 3 0 1 0;
#X connect 3 0 1 1;
#X connect 6 0 9 0;
#X connect 7 0 6 0;
#X connect 9 0 2 0;
-------------- next part --------------
#N canvas 0 0 454 304 12;
#X obj 59 91 osc~ 200;

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