Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!shadooby!samsung!uunet!microsoft!brianw
From: brianw@microsoft.UUCP (Brian Willoughby)
Newsgroups: comp.sys.apple
Subject: Re: OKS SCSI controller & TWgs
Keywords: SCSI, OKS, Cache, TransWarp
Message-ID: <9016@microsoft.UUCP>
Date: 14 Nov 89 05:15:21 GMT
References: <8911021825.aa11210@SMOKE.BRL.MIL> <89309.185534SAB121@PSUVM.BITNET> <3623@puff.cs.wisc.edu> <7312@ingr.com>
Reply-To: brianw@microsoft.UUCP (Brian Willoughby)
Organization: Microsoft Corp., Redmond WA
Lines: 35

In article <7312@ingr.com> gentrys@ingr.com (Scott Gentry) writes:
>In article <3623@puff.cs.wisc.edu>, blochowi@rt8.cs.wisc.edu (Jason Blochowiak) writes:
>> 	Anyways, does anyone know if the conflicts with the TransWarp GS have
>> been resolved? I was told that the TWgs had problems with the Multi-Kache card
>
>No problems here with my 7.0mhz TWGS and Multi-Kache board w/SCSI. There was
>however, a reprint of an article that stated to have IRQ on when using 
>Multi-Kache with a TWGS.  I've tried IRQ both on and off with no problem. 
>One small thing that I've not really been able to explain.
>-- 
>*Scott Gentry

I believe that the intended meaning was to use RDY and not DMA on the
Multi-Kache Card when a TWGS is used.  The Multi-Kache Card has a few
options to speed up disk access.  The *fastest* method is to use Direct
Memory Access, and I know that this will not work with the original
TransWarp.  I assume that it also does not work with the TransWarp GS
because the GS version uses cache memory to speed access to RAM and
therefore the cache might not be updated by a DMA access from the Kache
Card to main memory.  Keeping a processor cache updated in any multiple
bus-master system is not a trivial problem.  I'm surprised that such
technology is even working on the Apple II.  Disabling DMA causes the
Multi-Kache to use RDY, which is not nearly as fast as DMA, because the
65xxx processor must do all the memory moves.

I recently took advantage of Ohio Kache Systems' 15 day, no-risk trial.
There was no IRQ switch - only "Read Ahead", "Delayed Write" and "DMA".
I didn't have the SCSI option - is IRQ an option on the SCSI daughter
board?  BTW, the card didn't work with my TransWarpped 65C802 II Plus.

Brian Willoughby
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