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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?

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 -

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