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From: neese@adaptex.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: ESDI or SCSI or RLL?
Message-ID: <25100007@adaptex>
Date: 26 Mar 90 16:08:00 GMT
References: <18758@boulder.Colorado.EDU>
Lines: 44
Nf-ID: #R:boulder.Colorado.EDU:18758:adaptex:25100007:000:1988
Nf-From: adaptex.UUCP!neese    Mar 26 10:08:00 1990


>Well, most people out there seem to think that scsi is the fastest and edsi
>gets you more bang for the buck.
>I saw an advertisment for Jameco: EDSI $169.95  @  15m/bits / second
>                                  SCSI $349.96  @  10m/bits / second
>seems like esdi is better all the way around!
>
>any comments?

Firts SCSI is not a bus that is measured in bits/second.  High end SCSI
drives are running at 24Mhz today.  

The price of 349.00 is high.  I have seen street prices for the AHA-154xA
adapter at about 279.00.  Still more than ESDI, but the 154xA is a very
intelligent SCSI adapter that can't really be completely utilized under
MS-DOS.

My opinion:

ESDI is great for MS-DOS, as long as all you want is hard drives.  But if
your system will have a QIC tape drive, CD-ROM, WORM, DAT or Exabyte, then I
would go SCSI.  You save the cost of another board/controller in the system.

SCSI also offers an easier upgrade path.  For instance, many of you have
already run into the night,are of moving from a 10MBit ESDI drive to a
15MBit ESDI drive.  You already know that you have to replace your controller
to do that.  And when you want to move to a 20MBit ESDI driver, you will
have to do it again.  This is not true with SCSI.  SCSI doesn't care about the
drive data rate.

SCSI is more of a pain to move to due to the fact that there is not a standard
in the industry for it.  Adaptec, WD, Future Domain, and others all
have a SCSI adapter boards, but none of them are compatible with the others.
The other problem with SCSI is the performance you want is virtually up to
the SCSI device you use.  For instance, on my Quantum PRO80 drive I can get
about 3.2MBYtes/sec data throughput, under DOS.  With a Conner CP3100 drive
I get about 500KB/sec.  Big difference.  ESDI does not suffer from this.


			Roy Neese
			Adaptec Central Field Applications Engineer
			UUCP @ {texbell,attctc}!cpe!adaptex!neese
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