MINIX on PS/2 Model 25 !
sal...@tramp.colorado.edu
I have been trying to get MINIX 1.2 to run on a PS/2 Model 25
with a 720KB 3.5" Diskette drive. I seem to be getting the
same problems people are have on the Model 50 even though
model 25 uses an 8086 and 720KB drive (not 1.44) and no
microchannels ( as far as I know). I think
The problem is in floppy.c because the DMA of the Boot diskette
works fine in the case of a warm as well as a cold boot. Once I
get the initial menu and type '=', one of two things happen:
1. The system hangs up with no explanation.
2. The system writes the message that a trap < 16 occured then
hangs up.
Since noone on this newsgroup have mentioned anything about
model 25, my two questions are:
1. Has anyone tried to run minix on a PS/2 model 25, and if so
has anyone got it to work or at least got the same problem?
2. Am I heading in the right direction with the problem? I was
planning to do some work with floppy.c and recompile the kernel
and build a new diskette but since I have to do this on a PC then
DOS copy the diskettes onto 3.5", this could take me several hours
before I can run home and try it on my PS/2. Does anyone have
any seggestions on what to do???
Any information will be greatly appreciated.
Bassam Saliba.
University of Colorado-Boulder.
Andy Tanenbaum
> I have been trying to get MINIX 1.2 to run on a PS/2 Model 25
> with a 720KB 3.5" Diskette drive. I seem to be getting the
No. You are actually having different problems. The simplest solution is
to try V1.3. This has been thoroughly tested on a Model 30 and works fine.
It is hard to imagine that it won't work on a Model 25. There are a few
important differences between 1.2 and 1.3 that have been put in especially
for the PS/2 model 30, such as fussing with the planar control register.
The current suspicion about the Model 50 is the level-triggered interrupts.
When an interrupt comes in and is handled, the code normally does an IRET
instruction, and with level triggered interrupts the same interrupt may
happen again, endlessly, until something is done about it. I think this
problem has to do with the Microchannel, and shouldn't be present on the
Model 25. Still, anyone who has suggestions, please post them here.
Andy Tanenbaum (a...@cs.vu.nl)
mb
I worked on a IBM PS/2 Model 80 and had simular problems when I was
doing a project dealing with the Floppy Controller. It seems that the
SPECIFY command cannot accept the same values for the PS/2 as for the AT.
Theses exact values can be located in lower memory (I believe somewhere below
0x4000 - See the PS/2 BIOS Tech Ref for the location). Unless the controller
is given the correct values, it will cause things like: loss interrupts,
bad read/writes, media change status, and various other *wonderful* problems.
I hope this helps some...
Mike Burg
altos86!mb