Hi,
Well none of the answers were really scientific, so I'll just summarise.
Basically no one seemed displeased in anyway with the Alpha Personal
Workstation.
Performance did not seem to be a problem.
The cache size on the Alpha Personal Workstation can be 0 or 2mb, the
AlphaStation comes with 2mb standard unless its a 500/500 when 8mb is
thrown in. That is on the APW you need to order the cache. So for most
boxes the cache can be made to be the same ie 2mb (it just needs to be
specifically ordered for the APW).
Someone suggested that if you have cache intensive code, (I guess with a
lot of data, or badly optimised code), the APW can be run with no cache
to remove any "out of cache" messages, in which configuration it
probably has a wider data path, sounded a bit above me.
There was some indication that the cache on the APW was better better
matched to the cpu, again I've got no idea on that.
CPU.
The cpu in the APW has the same number as the cpu in the AS. Not sure
that that guarantees the same basic functionality on both architectures,
I assume that it does. Obviously the chip can be clocked at the same
speeds on both the APW and the AS, so there is no advantage I assume
there.
Bandwidth:
Marco Luchini wrote that there was twice the memory bandwidth on an AS
as a APW.
Overall speed:
There was a suggestion that the AS500/500 (an 8mb cache machine) ran 45%
faster than an APW 500au, not sure about this. DEC has published
performance figures, try looking around
http://www.digital.com/hpc/news/news_spec_november18.html
The au numbers don't look that bad.
Scsi
DEC is placing limits on the time and number of cards you can put in a
APW. Out of the box you should get Ultra + Fast + Wide Scsi via a
Q-logic scsi card. DEC will not support a second scsi card according to
our reseller, in most situations where you just want to hang a few disks
off the machine that is not a problem, but if you want to use the
machine to write various tape formats using a number of oldish narrow
scsi tape drives (my case), it can present problems.
One reply suggested that they had to run the scsi at fast scsi II for
their 2x23gb HDD's, meaning I guess that they were forced to go narrow
(ie 8bit) and so they didn't get upto Ultra speeds. I know that the scsi
bus is limited by the capabilities of the slowest device on the bus.
Future:
There was an indication that DEC was going to rationalise further, with
standardisation on shapes and boards across their Intel and Alpha
ranges. I think the mini tower (APW) is a better shape than the flat pc
shape (AS), anyway.
Dennis
mcdonell_at_auslig.gov.au
Received on Fri Dec 19 1997 - 01:30:38 NZDT