Path: utzoo!utgpu!attcan!uunet!ncrlnk!ncrcae!hubcap!gatech!rutgers!bellcore!texbell!killer!aimania
From: aimania@killer.DALLAS.TX.US (Walter Rothe)
Newsgroups: comp.sys.amiga
Subject: 2090A problems
Keywords: 2090A, DMA, overscan
Message-ID: <6055@killer.DALLAS.TX.US>
Date: 10 Nov 88 06:50:15 GMT
Organization: The Unix(R) Connection, Dallas, Texas
Lines: 32


I was almost ready to plop my money down and get a 2090A controller until a
couple of things happened. Up til that point all the benchmarks I had seen
seemed to favor the 2090A over the other disk controllers. But there appears
to be a problem with using it with larger screen resolutions. AMAZING
computing just came out with an article that shows that the 2090A slows
way down when doing a 704 by 644 by 4 bitplane overscan display. I would
expect some slowdown since this leaves only 50 slots out of a total 226
to do all other DMA and CPU cycles during one scan line.
However, there should be plenty of time
during vertical retrace to get the needed disk activity in. Other controllers
seem to be able to do this but the 2090A does not seem to be able to use
this time. What's going on?

One of my dealers in town said the 2090A's he got shipped did not work in
interlace mode. He said they crashed the system. Could this be true?

In fairness, I should also mention that the Supra drive had some screen update
problems in the overscan mode, but it still transfered data at a respectable
rate.

Another question about the 2090A.
If you bought a SCSI disk that would spin up faster, could you use the 2090A
to autoboot or is there a hard limitation with any SCSI drive?

Anybody seen an 80meg Quantum drive for less than $1029?

Thanks Commodore for a great job on 1.3

-- 
Walter Rothe at the UNIX(Tm) Connection, Dallas, Tx
UUCP: {rutgers}!smu.killer.aimania