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From: pk@wet.UUCP (Philip King)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Anyone own an ICD SCSI hd controler? Others mentioned..
Message-ID: <2254@wet.UUCP>
Date: 29 Mar 91 04:19:47 GMT
References: <91084.191834IO91461@MAINE.BITNET>
Organization: Wetware Diversions, San Francisco
Lines: 54

In article <91084.191834IO91461@MAINE.BITNET> IO91461@MAINE.BITNET (Tom Nezwek) writes:
>
>  Does anyone have an ICD hd controler and wish to comment on its
>performance?  Dperf2 results?  The reason I ask is that this is a

Well, I have an 'ADscsi 2000', or as they used to call it an 'Advantage
2000' SCSI host adaptor.  I use it with a Imprimis/Seagate 94350-230S/
ST-1239N 200 Meg. drive, which is rated at 15ms access.

While I don't seem to have the figures handy, it seemed to peak out
at somewhere around 600k reads, on my unaccelerated A2000.  This seems
to jibe fairly closely with the readings ICD publishes using Quantum
drives of similiar performance.  In those specs, it shows the ICD to
be faster than nearly every other controller shown (which includes the
GVP II, Wordsync, Trumpcard, 2091, and others) in most parameters.  Since
the ICD is not a DMA device, and since it uses data caching, the specs
are particularly impressive on an accelerated Amiga.  The only card that
had any significant number of parameters where it occasionally beat the
ICD (according to their tests) was the HardFrame.

On the other hand, someone mentioned recently in one of the Amiga 
newsgroups, that because of the algorhythm that ICD uses for caching,
some bad stuff could happen if the cpu happens to crash at certain 
moments.  I don't know much about that.  I don't have much experience
with a _good_ DMA controller (the A2090 I had before doesn't qualify!),
so I don't know what the differences would be.  I do notice with the 
ICD that screen updates don't appear to happen until the transfer/directory
scan finishes.  This may be due to the fact that non-DMA controllers
tie up the CPU more.  

The reason I bought the ICD was the price, the (reputed) speed, and the
removeable-media support.  Before anyone else, ICD claimed to support 
auto-diskchange, and to this day I believe they are the only ones who
say you can interchange _differently partitioned_ Syquest cartridges
without having to restart everything.  Unfortunately, the documentation
I received with my board is pretty sketchy...one of the few that comes
close to rivalling Commodore in that respect, unfortunately.
 
By the way, I tested the speed with Diskspeed 3.1, which is by all 
accounts a superior benchmark program to Dperf2.  Khalid Aldoseiri,
who wrote Dperf and frequents CI$, noted some of its limitations 
himself, such as choking at very high data-transfer rates.  I believe
Diskspeed 3.1 is either PD or shareware, and commonly available.  It
might help to have a standard frame of reference for these comparisons.
> 
> 
>                      -Tom Nezwek




				Philip
				pk@wet.uucp
				{ucsfcca,claris,hoptoad}!wet!pk