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From: bumy@vax5.CIT.CORNELL.EDU
Newsgroups: comp.sys.ibm.pc
Subject: Re: Some questions about a Leading Edge Model M
Message-ID: <18631@vax5.CIT.CORNELL.EDU>
Date: 17 May 89 20:37:26 GMT
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     This is my first attempt at posting so in case the subject line isn't
correct, the topic is the Leading Edge model M.

     I missed the original post but caught the reply in item 30128.  I'm 
putting down some of what I've learned about the macine in the last 2 years.

     The operating system can be upgraded to IBM-DOS 3.1 but no higher.  This 
can be done on most of the Model M machines but some have an earlier BIOS which 
is not compatible; an upgraded chip was available last year but I didn't need 
it. (phone #'s at end) The only way to know for sure is to install it.  If it 
hangs for no apparent reason in mid operation, the BIOS is probably at fault.  
My machine has been running on IBM-DOS 3.1 for about 10 months with no 
problems.  The BIOS chip reads (Mitsubishi C 1984 WESY30 | k16 | A).  Other 
brand BIOS chips will get you some functions but the screen is really wierd 
(don't ask how I know), basically the hardware doesn't match.  If you change 
DOS you will need a clock as the original won't function.  Also, the hard disk 
will have to be reformatted.  The jump from Leading Edge DOS to IBM-DOS is too 
much and the directories won't read.  The upgrade in DOS allowed me to use some 
new programs which functioned better with 3X, in fact 1 program requires DOS 3 
or higher.  I don't know about MS-DOS compatibility and, as I understand it, 
the problem with 3.2 and up is that the floppy will no longer format correctly.
     I replaced the 8088 with a V-20 and boosted the performance considerably.  
The Norton Index is 2.9, the graphics really zip, and I found that the hard 
drive loaded in about half the time (30 S for a file that had taken 55).  BUT, 
I don't recommend the procedure because the CPU is soldered on the 
motherboard.  I unsoldered it and installed a socket with the V-20.  It is not 
a trivial task, but I'm a hardware hacker and I like to play with hot soldering 
irons.
     The original hard drive is a Miniscribe model 3425 (note to make this a 
drive 2,  set switches 2,3,4,7 on).  It's sitting on the bench beside me 
because I pulled it last night and installed a Seagate 238-R and a WD 1004A-27X 
controller.  20 Meg was just too small for our current needs.  The controller 
is an Adaptec full length card. I don't see any specific indication of model 
but there are a lot of numbers on it and a 1984 copyright notice.  There was no 
problem installing 30M drive and one other lab here has done the same running 
Leading Edge Dos.
     Be aware that if there are interrupt conflicts, the processor downshifts 
to low speed and stays there.  There is no indication of changeover except the 
screen glitches.  I found this one when I installed a mouse and the machine ran 
OK until the first time I pressed the button, then it became sluggish.

     Phone numbers I used last year for inquiries
           Leading Edge Customer support 617-821-4300
     The parent company is Mitsubishi and they also helped with some other info 
213-515-3993.
           I don't know the current status of any of the phone lines or who 
owns what company or division.  The machine itself is a Sperry design and it 
was suggested that I might be able to upgrade with their DOS.  I have no 
further info on that possibility.

Additional note
     I've been working with DECNET-DOS ethernet link to a VAX for the past 8 
months and have some observations about its problems.  And, it does have some 
really neat functions and works well for us.  If there is any interest I can 
post what I've learned, however, I'm not sure this is the right group.
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                                        *
SOMETIMES IT IS NECESSARY TO GRAB THE   *               Jerry M. Wright
BULL BY THE TAIL AND FACE THE SITUATION.*          Department of Pharmacology
                                        *                   NYSCVM 
*****************************************              Cornell University
BUMY@VAX5.CIT.CORNELL.EDU               *               Ithaca, NY 14853 
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