harald@leo.UUCP ( Harald Milne) (03/30/88)
Another opinion.
Owning an A1000 with a Supra Drive 20meg SCSI drive and a
A2000 with A2090 controller and Seagate 251 drive, I feel somewhat
qualified to make the following statements.
For reasons I can't understand, (and I do understand the reasons
for SCSI speed improvements) the A2090 seems do better. My A2000 has
a very snappy response compared to the A1000 with SCSI. With all things
being equal (like number of top level directories, diskbuffers, etc)
and things being unequal (SCSI track buffering, average access times)
this is really strange.
Unfortunately, there are no current disk benchmark statistics for
these configurations to back up what I feel is so.
I don't have any notion of A2090 SCSI performance, so I can't even
even talk about this, but considering the supposed performance advantages
of SCSI against the A2090 controller with a slow access (40ms) 251 drive,
I'll be dammed if the A2090 doesn't kick ass so to speak. As if the A2090
provides SCSI performanc with an ordinary ST506. (Quite possible)
I don't know, and I don't have hard numbers, but the A2090 really
kicks.
It makes deciding to use SCSI or ST506 a monetary decision.
Anybody have the same experience?
I just happened to go with the ST251 drive for monetary reasons.
I was really suprised to see a drive twice as slow without track
buffering run so fast.
Needless to say, I'm impressed with the A2090 controller in this
configuration.
Any comments?
--
Work: Computer Consoles Inc. (CCI), Advanced Development Group (ADG)
Irvine, CA (RISCy business!)
UUCP: uunet!ccicpg!leo!haraldpapa@pollux.usc.edu (Marco Papa) (03/31/88)
In article <2911@leo.UUCP| harald@leo.UUCP ( Harald Milne) writes: | For reasons I can't understand, (and I do understand the reasons |for SCSI speed improvements) the A2090 seems do better. My A2000 has |a very snappy response compared to the A1000 with SCSI. With all things |being equal (like number of top level directories, diskbuffers, etc) |and things being unequal (SCSI track buffering, average access times) |this is really strange. | I don't have any notion of A2090 SCSI performance, so I can't even |even talk about this, but considering the supposed performance advantages |of SCSI against the A2090 controller with a slow access (40ms) 251 drive, |I'll be dammed if the A2090 doesn't kick ass so to speak. As if the A2090 |provides SCSI performanc with an ordinary ST506. (Quite possible) | | I don't know, and I don't have hard numbers, but the A2090 really |kicks. | Needless to say, I'm impressed with the A2090 controller in this |configuration. | | Any comments? I have your same configuration (A2090 and ST251) and I concur completely with your assessment. Even more. I have partitioned the ST251 with an FFS (Fast File System) partition (1.3 Gamma). Icons come up from that partition AS FAST AS from the 1.3 C-A Recoverable RAM Disk. Note that I DON't have the "fast" 28msec ST251-1, but the "slow" ST251 (40 msec). -- Marco Papa -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= uucp:...!pollux!papa BIX:papa ARPAnet:pollux!papa@oberon.usc.edu "There's Alpha, Beta, Gamma and Diga!" -- Leo Schwab [quoting Rick Unland] -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
cmcmanis%pepper@Sun.COM (Chuck McManis) (03/31/88)
In article <2911@leo.UUCP> harald@leo.UUCP ( Harald Milne) writes:
-> Another opinion.
-->
-> Owning an A1000 with a Supra Drive 20meg SCSI drive and a
->A2000 with A2090 controller and Seagate 251 drive, I feel somewhat
->qualified to make the following statements.
->
-> For reasons I can't understand, (and I do understand the reasons
->for SCSI speed improvements) the A2090 seems do better. My A2000 has
->a very snappy response compared to the A1000 with SCSI. With all things
->being equal (like number of top level directories, diskbuffers, etc)
->and things being unequal (SCSI track buffering, average access times)
->this is really strange.
Actually it isn't quite so strange. You see the 2090 is a DMA driven
device, basically it dumps stuff into memory for you automatically.
The Supra (and many other SCSI interfaces for the 1000) are interrupt
driven i/o, which is slower. Something else to look forward to, the
Fast File system is 10 - 50% faster than what you have now. Zooom city
as they say. Basically, it just keeps getting better and better...
--Chuck McManis
uucp: {anywhere}!sun!cmcmanis BIX: cmcmanis ARPAnet: cmcmanis@sun.com
These opinions are my own and no one elses, but you knew that didn't you.R38@PSUVM.BITNET (aka Marc Rifkin) (04/01/88)
The 2090 is impressive, but for some of us home users, it would be an
overkill for its price and potential. What I'd need would be a decent
low cost 1-drive SCSI (DMA?) controller.
-------
]Please excuse any temporal discrepencies with what I say...
]...My temporal perception has discrepencies.
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