More Bringing up a CPM

From: Dwight Elvey <elvey_at_hal.com>
Date: Fri May 28 11:58:00 1999

Hi
 Wanted to say thanks to all that have responded.
To clear up some things, I'd describe what I have
and what I want to do.
 The IMSAI has an old TTL disk controller ( no micro
or controller chips). It is a setup made by Digital Systems.
It includes a bus interface card called HB-1 and the controller
is called FDC-1.
 It is an original IMSAI processor. It currently has 48K
of 2101 type static RAM ( a lot of RAM chips ). I can
make it 64K with other RAM cards that I have but that
is not my intent.
 The disk controller is designed to read Trk0Sec1 on a reset
pulse from the S-100 bus. I have written a boot loader and
have put it on this sector. I also put a simple serial
loader here as well so that I can move data from my PC to
the IMSAI and then I can store it on the disk. The controller
runs on a bipolar PROM driven state machine. Although
I could program it to do other things, that is not my intent.
 I have used a schematic and made a listing file for the
code in the controllers state machine. If anyone has one
of these and would like a listing of this, let me know.
The reason I did this was to find out how to use the controller
to format a disk. It required a track image, similar to
the 177x/179x type controllers but was some what modified in
that the image doesn't need gap data or crc's. These are
generated by the controller.
 I have had no experience with CPM. I've worked with things
like ISIS and MSDOS at low levels but just never got around
to dealing with CPM.
 My next question is, could someone send me an image of a
directory that I could use to build my disk? I have info
on what it should look like but don't want to completely
hand build it. It can have several files names in it and I
can modify it after getting my CPM and BIOS up and running.
This should be a 2.2 type directory.
 Also, when doing a MOVCPM, how does this program know
how to patch all of the addresses in the code? The reason
I ask is that it looks like the image that I down loaded
is setup as a 62K CPM. I'd like to make it simple to
get it back into the normal 20K position first so that I
can work within my current addresses ( yes, I know I can
just make a hole in the memory and move some up to the
high end ).
Dwight
Received on Fri May 28 1999 - 11:58:00 BST