Why etc.

From: Dwight Elvey <elvey_at_hal.com>
Date: Mon Mar 13 12:05:03 2000

Technoid_at_cheta.net wrote:
>
> 10) Is documentation available? It may also cost you and you may not be
> going anywhere without it.
>
> 11) Can you get boot media and IPL media for it? If not it will just sit
> there and look pretty to others but you will KNOW it is dead every time
> you look at it. Some collectors don't mind but I can't stand a dead
> machine.

Hi
 I brought a IMSAI with a strange TTL state machine disk
controller back to life without any boot media. I was
able to locate schematics for it and then read the
PROMs. I made my own mnemonics for it so I could understand
what it wanted me to send to is, both port and memory data.
It used DMA and may have been one of the earlier DMAs
used for disk interfaces on the s100. Still, I wrote
some code to format disk and transfer information from
memory to and from the disk. I wrote a BIOS for CP/M
and created a bootable disk. I now have a working
CP/M system. I could have taken a newer disk board and
replaced the 8080 with a Z80 board but I wanted it to
work as much like the original as I could. I'd rather
have had original copies of the code that came with it
but one does with what they can get.
Dwight
Received on Mon Mar 13 2000 - 12:05:03 GMT