> Look at the reality! If you have to do this sort of thing, x86 will give
> you headaches. Normal 133MhZx32Bit PCI is _way_ too slow for that
> machine. The entire PCI bus cannot saturate _one_ Ultra160 SCSI
> controller, let alone a GigEth card. Putting More than one into a box
> and trying to use them concurrently will show you what good normal PCI
> is for _really_ fast hardware. You sure want multiple PCI64x66Mhz busses
> and _now_ look again at board prices for x86.
I'm not planning on 32bit bus - and the 64bit bis mobo's - while more
expensive are not ridiculously more expensive. - not on the scale of
alphas.
Additionally the administrative costs of alphas is higher - getting new
parts means going through only a few vendors - less competition, higher
prices and shittier service. I'm not happy with alphas at all.
> Also, if you do data analysis like setiathome does (i.e. mostly FP),
> alphas blow away _any_ other microprocessor (setiathome work-unit in
> less than an hour; my AMD K6-2 500 needs 18hrs!) Code can be re-compiled
> and probably should.
this is fermilab's code - you recompile PAW and all the other stuff for
alpha. We're talking weeks and weeks of work. This is SERIOUSLY non
trivial amounts of code. And telling the profs here to do that would be
suicide.
> Look, you are an the _very_ wrong track! You may have 6 or 7 PCI
> _slots_, but you have only _one_ bus, i.e. only 133MB/sec bandwidth for
> _all_ 6 or 7 devices. You will not get 90MB/sec real throughput with a
> bus bandwidth of 133MB/sec! And the x86 architecture's memory bandwidth
> is _tiny_ (BX chipset does one or two _dozen_ MB/sec random access, ie.
> 12-24 MB/sec).
Multiple busses in some of the larger vendor's X86. And I've already
gotten some raid0 benchmarks from people on the hardware I was looking at
getting > 80MB/s read performance.
Additionally I have a plain old single celeron with 3 7200 rpm 18gig
scsi's - u2w on a tekram controller. I get 25-30MB/s in raid0 so obviously
your above figure of 24MB/s is wrong.
so its not only possible, its happening.
-sv
