Path: utzoo!utgpu!water!watmath!clyde!rutgers!husc6!cmcl2!kaplan
From: kaplan@cmcl2.NYU.EDU (Laurence S. Kaplan)
Newsgroups: comp.sys.ibm.pc.rt
Subject: Re: OEM Disks for RT?
Keywords: ESDI?  Extended ESDI?
Message-ID: <22641@cmcl2.NYU.EDU>
Date: 15 Jan 88 16:52:59 GMT
References: <362@pan.UUCP>
Reply-To: kaplan@cmcl2.UUCP (Laurence S. Kaplan)
Organization: New York University
Lines: 32

In article <362@pan.UUCP> jw@pan.UUCP (Jamie Watson) writes:
>
>Has anyone ever tried putting 3rd party disks into an RT?  Exactly what
>kind of disks does it take?  The documentation says that the original cpu
>machines use ESDI disks, while the new systems use Extended ESDI disks.
>What is the difference between these - is it only a controller or formatting
>issue, so the disks are physically the same?
>
>If anyone has specific information about manufacturers or types of disks
>that are known to work, that would be very helpful.
>
>jw

As I have mentioned before in this news group, here at NYU we are currently
using three Micropolis 1355 (150 Mbyte)  disk drives on both ESDI and EESDI 
controllers from IBM.  Under ACIS 4.3 no code modifications are necessary 
(though they make things a little easier).  Contact Micropolis for information
about distribution in your area.  We also have on order a 1558 which gives
about 330 Mbyte formatted.

The difference between IBM ESDI and EESDI is that EESDI can use disks 
interleaved at 1:1 while ESDI needs 4:1.  Also EESDI can support up to
15Mhz transfer rates and multiple outstanding requests (assuming multiple
drives on the controller).
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Laurence S. Kaplan						     |
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