Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!usc!rpi!crdgw1!sixhub!davidsen
From: davidsen@sixhub.UUCP (Wm E. Davidsen Jr)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Need help: MFM & RLL drives on same box??!!?
Message-ID: <3441@sixhub.UUCP>
Date: 17 Mar 91 21:19:03 GMT
References: <1149@ra.MsState.Edu>
Reply-To: davidsen@sixhub.UUCP (bill davidsen)
Distribution: na
Organization: *IX Public Access UNIX, Schenectady NY
Lines: 43

In article <1149@ra.MsState.Edu> pam1@ra.MsState.Edu (Phillip A. McReynolds) writes:

| 1.  Try to RLL the MFM drive.
| 
| - Probably won't work since the MFM is a Seagate.  Storage would be unreliable 
| in any case.  Besides, this probably isn't the best option for me since my RLL 
| controller is 8 bits (an ST11).

  I ran this system 24 hours a day for over a year with Seagate 251-1
and 4096 drives. I picked up about three bad sectors over that time, and
I think they may have been caused by bad power, since I have seen the
same rate with MFM and ESDI in systems here.

  My reliability was much better with the WD1006VSR2 than several other
RLL controllers I tried. Since this system often has the disk light on
for hours at a time, I doubt that you would beat you system any harder
than I do.

| 2.  Try to MFM the RLL drive.
| 
| - A good idea?  Will this work at all?  Would it be reliable?  Presumably the
| RLL specs are tighter than the MFM specs so that if 1) I bought an MFM card
| (16 bits) I might actually improve performance on the RLL drive although I'd
| reduce its storage capacity.

  Seems to me I did that with a 4199R or whatever the 4096 RLL version
is. I was waiting for a controller and needed some rotating storage
right then. You lose a lot of storage, though.

| 3.  Get a MFM controller and try to make the two controllers work in the same 
| box at the same time.
| 
| - I'm told that this won't work at all because there'd be memory address
| conflicts.  Is this true?

  It's not true under SCO UNIX and Xenix. What's possible under DOS I
wouldn't venture to say. You need to move the BIOS and i/o for DOS, also
the interrupt for UNIX.
-- 
bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen)
    sysop *IX BBS and Public Access UNIX
    moderator of comp.binaries.ibm.pc and 80386 mailing list
"Stupidity, like virtue, is its own reward" -me