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SIMH/os8diskserver/PDP-8

And why not!

You've done a marvellous job in bringing this machine back to life - so you deserve to enjoy it a bit. I am sure you will find that you want to expand it as time/money becomes available in the future.

Here are a few ideas if you have a parallel I/O card. The M863 is a parallel I/O card - but interestingly I can't find much information on it. Can you post a photograph of it?

https://www.youtube.com/watch?v=fj3fjYL_QsM

https://www.youtube.com/watch?v=B1MDYYvw0cY&nohtml5=False

Don't hesitate to post any more questions you have. It is always a pleasure to help out. But don't forget that envelope of luck you promised me in finding my own PDP-8!

Enjoy,

Dave
 
Just to answer your question regarding libraries...

The library files are stored in FORLIB by default. I think there may be a switch somewhere to persuade one of the software tools to use a library file other than FORLIB if required (I remember reading that somewhere in the language manual I think).

There is a tool for manipulating library files called LIBRA. This tool permits you to list, delete and add (amongst other things) to a library file. For example, you could remove all of the double precision and complex functions from FORLIB to prevent them from being used if you were never going have (and therefore never going to use) the FPP hardware.

You could also (in theory) have re-written the double precision and complex functions in FLAP to be in purely in software and NOT require the FPP hardware. I wonder if anyone has ever done this and the associated files are on the internet somewhere?

I looked into the FORTRAN source code for the run-time system and I can see where the checks are done for the FPP hardware and where the "CAUTION - NO DP" message is displayed. The comment is interesting by the code "BUT LET THE FOOL GO ON":

Code: 
	TAD	DPFPP
	TAD I	(QDPFLG	/CHECK IF TRYING TO USE D.P. WITHOUT OPTION
	SMA CLA
	JMP	.+3
	JMS I	(RLERR	/YES - PRINT WARNING MESSAGE
	NODPMS		/BUT LET THE FOOL GO ON

FLAP seems to have a DPCHK pseudo-operator which 'flags' that the code being assembled requires the FPP hardware. I assume it is this pseudo-operator which is used by the run-time system to identify if any runtime functions require the FPP hardware and (if not found) displays the "CAUTION - NO DP" message. It would be interesting to remove all the double precision and complex functions from the FORLIB library and try and just re-write one of them in FLAP PDP-8 software to see what would happen. Am I leaving myself open here for doing some experimenting I wonder...

Dave
 
Gee... is that Kyle? Just a young man with such a intelligent mind.

The 'FOOL'? Now, how did they know I was poking around here?

It might be interesting to attempt to write some FP software, but I don't think I have enough years left to get that done.

Here is the M863

IMG_0303.jpgIMG_0302.jpg

Someone printed on the card 'KT85-0255'. I wonder what that means. The card has two 40 pin connectors that connected to the Kearney Tracker cards. There are a bunch of jumpers, must be for an address code and maybe something associated with the port bits? I have not looked for any info yet. Mike
 
Just found the schematics for the M863. Looks pretty simple. It's 12 channel I/O, one input and one output. At the same time I found something called Floating Point Routines for the PDP8

DEC-08-YQ1B-PB
DEC-08-YQ2B-PB
DEC-08-YQ3B-PB
DEC-08-YQ4B-PB

They were only referenced with no documentation included. Are these some software FP routines to be added to the machine? Mike
 
Mike_Z said:
Gee... is that Kyle? Just a young man with such a intelligent mind.

The 'FOOL'? Now, how did they know I was poking around here?

It might be interesting to attempt to write some FP software, but I don't think I have enough years left to get that done.

Here is the M863

View attachment 30583View attachment 30584

Someone printed on the card 'KT85-0255'. I wonder what that means. The card has two 40 pin connectors that connected to the Kearney Tracker cards. There are a bunch of jumpers, must be for an address code and maybe something associated with the port bits? I have not looked for any info yet. Mike
Click to expand...

Heh, that's me! The tree kept getting software upgrades; I think that was v5 or so, it's up to v8, I believe. Red-green flashing, random fade and blink, varying speeds, all controllable from the front panel.

The M1705 doesn't have any input capability like the M863 does, but it turns out, the M1705 looks a lot like the VC8E interface for the point-plot display.

The jumpers on the M863 set how the inputs generate interrupts, as I recall. It's been a while since I looked at it. The M1705 is a much nicer (output) interface. I planned to kluge an M863 for a card reader interface, but I ended up getting an M843 CR8E interface for not too much.
 
I have been fiddling with a project for the last few years. I connected an Actel FPGA to the Omnibus. The FPGA contains an ARM processor that runs Linux. With a combination of "hardware" in the FPGA and software in Linux it could emulate any Omnibus controller and peripheral. Right now it will emulate a PC8E and paper tape reader. The paper tape images are stored as a file in flash in the ARM's filesystem.

I was working on emulating serial ports, and connecting the Omnibus serial ports to serial ports in Linux. When that works you could telnet into the ARM, then run minicom to connect to one of the 8/e's serial ports.

Theoretically you could create a new device were OS/8 would write a URL into a serial port, Linux would fetch the file, and then OS/8 could read the file through the serial port.

http://www.ricomputermuseum.org/Home/equipment/dec-pdp-8e/making-an-omnibus-peripheral-emulator
 
bobaboba said:
Things have overtaken me (not unusually) but in case it's of value to you I put some files up which might interest you. The page is at http://ccgi.theadamsons.force9.co.uk/pdp8software/os8diskserver/ .

os8v3q_160405.rk05 is a bootable OS/8 system disk for the os8diskserver. It's already got the SDSK device set as the system device so nothing to do but call it from the server as the first disk.
Click to expand...

I booted this image using serialdisk, enabled the RK8E handler, and copied the image to a real RK05 pack. Works quite nicely.
 
m_thompson said:
I noticed that the disk image has SDIS configured for 8 disks, but newserver only supports 4.
Click to expand...
That's the usual mechanism for 1 RK05 in the server being represented as 2 devices in OS/8 because of block number limitations. Disks 1-4 become devices A0/B0 - A3/B3, server codes A-H.
 
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