On 1/6/2014 11:23 AM, Marc Howard wrote:
Hi,
I've been bringing up a PDP-8a system over the past few months. It has 2 x
TU56 (TC08 controller), 3 x RK05J and a 3rd party RX01 dual floppy. The
processor itself is an 8e board set w/EAE and 32K core.
As for media I have 7 RK05 packs, one floppy and about 60-75 dectapes.
My first attempt at booting was with the RK05. It took a ton of cleaning
(and capacitor replacement/reforming) to bring up the 8, followed by
cleaning one of the RK05 drives. (BTW, this stuff apparently was in the
equvalent of a barn for at least 20 years by what I could see).
Anyway I cleaned 2 of the RK05 packs that seemed most likely to be bootable
media but no joy. The drive just seeks to cylinder 0 and sits there,
although I think a data transfer *might* have occured. I suspect that all
of the RK05 packs were for individual user backup. Apparently from the
documentation I have this system at one time had a RL01 attached.
Next I worked on the better looking of the two TU56's. I've got one drive
shuttling okay; the other half has no torque in one direction; I suspect I
need to replace yet another AC motor run capacitor.
The TC08 checked out okay and I replaced all of the das blinken lights with
new bulbs, it looks really cool.
Then the big test. I picked out a tape that had a listing with it
indicating that it was a system tape of some sort (Focal, editor, etc.)
I toggled in the TC08 boot code (since my M8317 has the wrong boot roms for
it) and hit run. The tape wound back to the beginning, reversed, seemed to
transfer many blocks of data and then just spins in a loop.
So the next step would obviously be to run some TC08/TU56 diagnostics but I
don't have any way of loading them.
If I had an RK05 pack with OS8 + diags on it that would work but I don't
see that happening. Perhaps another alternative would be to get the
equivalent on RX01 floppies from someone, but I don't even know if the
floppy system works yet.
So for now I think figuring out how to make a combo terminal emulator/raw
data file thingy might be the best way to go. I'm thinking of putting a
beagleboard to use for this unless anyone out there has a simpler/quicker
solution.
Suggestions anyone?
Thanks,
Marc
For my PDP-8m which only has serial cards, I load all software thru the
console port via the
RIM and/or BIN loader. I have one of the diode-ROM boot boards setup
with the RIM loader
for the console port, so the boot switch starts the RIM loader
listening. Then I download (using
Teraterm) either RIM format paper tape images, or the RIM format BIN
loader follower by BIN
format paper tape images.
Works just fine, and the process does not take long at 9600baud to load
one or two fields at
most of program image.
I don't know if the PDP-8a has a RIM and/or BIN loader for the console
(or serial PTR) in it's boot
ROM(s), but it would probably be fairly straightforward to
write/adapt/program a new BOOT ROM
if need be. It would most certainly be easier than reprogramming the
diode-ROM boot boards I
used on the 8m ...
Don