Article View: comp.sys.mac
Article #14793Re: Dataframe SCSI (was Mac SCSI perf. (was Mac-Sun SCSI connection))
From: howard
Date: Thu, 26 Feb 1987 23:15
Date: Thu, 26 Feb 1987 23:15
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2374 bytes
In article <6341@mhuxu.UUCP> davec@mhuxu.UUCP (Dave Caswell, sorta) writes:
> .....From an engineering
>standpoint, SuperMac's souped-up SCSI manager is *worse* than the original:
>it has more timing dependencies and works correctly with fewer SCSI devices.
> .
> .
> ....If you
>move too fast, you suffer over-run while writing or under-run while
>reading, and the Mac dies a confusing death. SuperMac's big speed-up
>comes from tweaking their data transfers so that they're precisely tuned
>to their disks. It's risky as hell, but they don't tell their customers
>that. Apple's blind transfers are deliberately slower so that they'll work
>with a larger variety of devices.
>
Ok. It all makes sense. But, how come my Mac hasn't died a confusing
death? I've run both a DF20 at various initializer levels as well as
my current DF20XP. Here's the rub; I have a Monster Mac board giving the
Mac an extra performance kick. If the timing was so tight, how come the
whole thing hums along without so much as a glitch. Did Ephriam actually
disassemble the Supermac driver to figure all this out? Will newer Macs
have sensible hardware? Will they have a sensible price? Will the Natl.
Enq. cover the new annoucements? I have an enquiring mind. I wanna know!
--
"Plan for the future because that's where you Howard C. Simonson
are going to spend the rest of your life." {hplabs,ihnp4,nsc}!amdahl!howard
- Mark Twain -
[ The disclaimer for this message may be found in my next article ]
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!utgpu!water!watnot!watmath!clyde!rutgers!seismo!lll-lcc!styx!ames!amdahl!howard From: howard@amdahl.UUCP Newsgroups: comp.sys.mac Subject: Re: Dataframe SCSI (was Mac SCSI perf. (was Mac-Sun SCSI connection)) Message-ID: <5760@amdahl.UUCP> Date: Thu, 26-Feb-87 18:15:38 EST Article-I.D.: amdahl.5760 Posted: Thu Feb 26 18:15:38 1987 Date-Received: Sun, 1-Mar-87 07:54:29 EST References: <6341@mhuxu.UUCP> Reply-To: howard@amdahl.UUCP (Howard C. Simonson) Organization: Amdahl Corp, Sunnyvale CA Lines: 28 Keywords: Supermac Dataframe XP "Lots of other trademarks" SCSI MonsterMac Summary: Fact and fiction, which is which, or am I just lucky?