Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!rutgers!mcnc!thorin!clocs!davis
From: davis@clocs.cs.unc.edu (Mark Davis)
Newsgroups: comp.periphs
Subject: ESDI 15/20 Mbit Drives on 10 Mbit Controller?
Summary: Will it work (slowly)?
Keywords: ESDI Transfer rate controllers disk drive
Message-ID: <11345@thorin.cs.unc.edu>
Date: 5 Jan 90 14:34:09 GMT
Sender: news@thorin.cs.unc.edu
Reply-To: davis@cs.unc.edu (Mark Davis)
Organization: University Of North Carolina, Chapel Hill
Lines: 19

What happens when a 15 Megabits/sec ESDI drive is connected to a
10 Megabits/sec controller?

For example, what happens if I put a 760 Meg drive on a PS/2 with the
IBM ESDI Fixed Disk Drive Adapater/A in it?  I know a lot about such
installations, because I have have installed a Micropolis 1355, but
that was a 10 Mbits/sec drive.

If it works at all, will there be bad effects?  For example, from
reading the Technical Reference I don't see any way to set the
interleave on the IBM ESDI/A adapter.  Will very poor performance
result because the interleave is too agressive?  Or will it just write
to the disk at 10Mbits/sec, reducing the total space on the disk to
10/15 of rated?

I assume the same question applies to 20 Mbit/sec drives on the 15
Mbit/sec controllers.

Thanks - Mark (davis@cs.unc.edu or uunet!mcnc!davis)