24 Oct
1999
24 Oct
'99
8:06 a.m.
Mike Cheponis wrote:
[stuff deleted]
Dunno; perhaps Allison does. Never was much of a VAX fan...
Best,
Chris
--
Chris Kennedy
chris(a)mainecoon.com
http://www.mainecoon.com
PGP fingerprint: 4E99 10B6 7253 B048 6685 6CBC 55E1 20A3 108D AB97
So, if it is not a typo on
http://www.digital.com/timeline/1990-4.htm
then my original assertion is, indeed, correct: The 6500 is 2x to 3x slower
than a dx2/66. ( And the vax 6000-530 is even slower. )
It looks to me like Allison was making an assertion about thruput in
a multiuser configuration. Thruput in a demand paged operating system
is generally bounded by I/O bandwidth, not CPU bandwidth, so the fact
that the 486 turns in better integer performance doesn't invalidate
her argument.
I don't know what it is about collectors that
somehow confuses their
memories of the past; maybe their internal core memories have suffered some
bit flips? ;-) (I have some old junk, too, so I consider myself in the
same camp...)
No confusion; there are simply different metrics for performance and she's
using a different one than you. You are both, in fact, correct. The 486
will outperform the VAX in integer performance, but the VAX has bundles
more bandwidth to disk than the 486 ever dreamed of.
Fact is, these old machines were slow, noisy, hot,
power-guzzling behemouths
compared with what we have today.
No argument there ;-)
[snip]
Therefore, to me, you have to measure the performance
in some repeatable
way. Dhrystone is not the perfect benchmark (which is close to an oxymoron
anyway), but it is -a- benchmark for integer CPU performance.
Right. To address Allison's argument you need to measure sustained and burst
bandwidth to disk.
[snip]
Apples and
oranges, the VAX especially the bigger models with the CI and
other high perf IO busses can easily pound PCI pentiums into the ground
for shear load.
Now, let's talk about busses. Just how fast -was- this CI? Let's compare
that with 66 MHz 64-bit PCI, which has 66e6 x 64 = 4,224,000,000 bits/sec
peak throughput. What was CI's throughput?