Path: utzoo!attcan!uunet!cs.utexas.edu!texbell!merch!cpe!adaptex!neese
From: neese@adaptex.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: EISA Disk Controller from IBM
Message-ID: <31300005@adaptex>
Date: 13 Jun 90 20:18:00 GMT
References: <18467@vicom.com>
Lines: 37
Nf-ID: #R:vicom.com:18467:adaptex:31300005:000:2011
Nf-From: adaptex.UUCP!neese    Jun 13 14:18:00 1990


>>Is anyone currently using the new ESIA bus interface disk controller
>>from IBM... the one which their literature claims supports over 16Mbytes
>>per second?  I'd like to correspond with anyone who is using it.
>>Pls reply directly to:
>>
> The problem here is that no disks are available that run that fast. The
>fastest commercially available disks are dual headed IPI-2 drives that can
>presently achieve 6Mb/s

Not that this answers the original posting, but....  This is quite correct.
I kind of chuckle at the folks who buy a 32Bit EISA SCSI adapter and think
they are going to get a big boost in performance.  It just isn't going to
happen until there are FAST (10MByte/sec) SCSI-2 drives.  Now if they
bought that EISA SCSI card and it can't support FAST SCSI-2, then they
really did get screwed.  Current SCSI technology can barely keep up with
streaming data at 2MByte/sec, much less 10Mbytes/sec.  At these speeds
(2MB/sec), a 16bit board can more than keep up.
For instance, our 154x board has the ability to move data across the AT
bus at up to 10MBytes/sec.  Even at the default speed of 5MByte/sec, the
board is laying around waiting for the drive.
Of course, it remains to be seen if the FAST SCSI-2 drives will be able to
stream at 10MBytes/sec or simply burst at that speed.  I suspect the latter
to be true.  They may only be able to stream at 5MBytes/sec.  Still slow
for a 32bit board which is capable of running at 32MBytes/sec.  But relatively
fast for a board that can only run at 10MBytes/sec.
The point being, the 16Bit boards still haven't been fully exploited, so if
you are the first on the block to have a 32Bit SCSI adapter, you will have
only gained the fact that you were first.  If that means a lot to you then
you win, but if performance was what you were looking for, then you didn't
gain much and spent a lot.

			Roy Neese
			Adaptec Senior SCSI Applications Engineer
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