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From: ridder@elvira.enet.dec.com (Hans Ridder)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Hard disk transfer rates
Keywords: Big, mean, fast & shiny controllers
Message-ID: <1688@shodha.enet.dec.com>
Date: 20 Sep 90 17:54:50 GMT
References: <3769@ruuinf.cs.ruu.nl> <14418@cbmvax.commodore.com>
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Organization: Digital Equipment Corporation, Customer Support Center
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In article <14418@cbmvax.commodore.com> daveh@cbmvax.commodore.com (Dave Haynie) writes:
>SCSI II isn't 16 bits wide, it's still 8 bits.  It specifies the SCSI command
>set in a much more standardized fashion than original SCSI, and has a fast
>synchronous transfer mode capable of 10 megabytes/second.  But it really 
>doesn't matter what your fastest transfer rate is capable of in a system, the
>limit is based on the slowest element in the link, whether that be A2000 bus 
>transfer speed, SCSI speed, or the hard disk's own speed.

I'm not an expert on SCSI II in any way, but what Dave says here is
contrary to to what I've read about it.  What I've read says that SCSI
II allows bus widths of 1, 2, or 4 bytes.  Using unbalanced tranceivers,
the maximum speed is 5 megatransfers/sec. (synchronous I assume), and 10
megatransfers/sec. using balanced tranceivers.  I dunno if they specify
a slower asynchronous speed or not.

So, a 4 byte wide bus using balanced transceivers could really move some
data (and would really cost quite a few samolians.)

Wish I had a copy of the spec. (it's 600 pages, whew!)

>Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"

-hans
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