Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!evax!utacfd!merch!cpe!adaptex!adaptx1!neese
From: neese@adaptx1.UUCP
Newsgroups: comp.periphs.scsi
Subject: Re: favorite SCSI controller chips
Message-ID: <283400028@adaptx1>
Date: 3 Jan 91 21:29:47 GMT
References: <1641@ksr.com>
Lines: 29
Nf-ID: #R:ksr.com:1641:adaptx1:283400028:000:1136
Nf-From: adaptx1.UUCP!neese    Jan  3 12:03:00 1991


>/* ---------- "favorite SCSI controller chips" ---------- */
>As a curiosity question, what do people think is the fastest (designable
>throughput as opposed to spec claims) SCSI chip out?  Which company will
>have the fastest in the next 6 months?
>
>My opinion:
>    Adaptec 6250
>	- 3 Mbytes/sec Async
>	- 5 Mbytes/sec Sync (using only an offset of 8...NCR's 53C90 needs
>	  an offset of 16 for this speed).
>	- 10 (8 bit bus) or 20 (16 bit bus) buffer DMA transfer.
>	- Arbitration and Selection into command phase done in hardware.

Actually, if you are design engineer working on an AT bus type implementation
the AIC-6260 is a better choice.  It has the AT bus built in and a much better
software interface than the 6250.  It does everything the 6250 does plus some
more stuff.  It also support FAST SCSI-2.

>    Next 6 months:  Adaptec with SCSI-2 chips (SCSI compatible connectors).

The AIC-6251 chip is out and also support FAST SCSI-2.

			Roy Neese
			Adaptec Senior SCSI Applications Engineer
			UUCP @  neese@adaptex
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