Re-visiting my PiDP-11 build

[terry-...@glaver.org]

5+ years ago, I built two PiDP-11 kits, using the version of Raspbian that was available at the time, along with the PiDP-11 software of the time. I had the "LED process dies" and the "knobs rotate the display in the wrong direction" bugs, and somewhere along the way a Raspbian update broke the automatic launch of the screen terminal that was the PDP-11 console.

I saved my heavily-customized from-scratch RSTS/E 10.1 install.

Since I had some time waiting for more things for my PiDP-10 to arrive (nothing that's Oscar's fault, I'm just making some changes) I decided to do a completely clean install, starting with the latest 64-bit Raspbian and then the install script that's part of the current instructions. BTW, this is a Pi 3B+ with X11, configured headless with VNC.

All went well, except for a few minor things:

1) The knob behavior is even more erratic now - turning either knob one click moves the displayed LED 0, 1, or more positions in a random direction. Is there a fix for this that never got integrated into the currently-downloadable binaries?

2) The emulated PDP starts up automatically, but without an emulated console in a terminal window. Doing a "/opt/pidp11/bin/pidp11.sh opens a terminal, but clobbers the currently running PDP-11 OS as it starts a new emulator instance. This is a 2-part question: a) Is there a way to get the original behavior where the emulated console terminal auto-launches on startup? b) Is there a command (screen, maybe) to attach to the currently running PDP-11 console instead of the pidp11.sh complete emulator restart?

I restored my custom RSTS/E 10.1 install and with some minor fiddling of the startup script to fix the paths to disk images, I was back up and running.

However, that did remind me to ask - the 2.11BSD disk image is dated Oct 8 2019 and the RSX-11M+ disk image is dated Jan 22 2019. Rather than going back and collecting the 2BSD patches, and all of Johnny's improvements to M+ since then, is there a place to download up-to-date disk images for those?

[Johnny Billquist]

For RSX, see http://mim.stupi.net/pidp.htm

I keep updating that whenever I do stuff. And that also means loads of
patches to RSX that are not available any other way.

Johnny

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--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: b...@softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol

[Steven A. Falco]

I recently swapped out the Pi3 in my PiDP-11 for a Pi4. I used the bookworm 64-bit image.

There is a mutex bug that may or may not have been fixed in the official code. The attached patch file helps the "LED process dies" issue, but for me, the fix is not perfect. My LEDs still lock up every few months or so. It is not frequent enough that I have bothered to chase it down.

As to the knobs being backwards, I had that problem. The fix is to edit /opt/pidp11/src/11_pidp_server/pidp11/gpio.c

At line 417, I now have:

knobValue[i]--; // reverse direction

and at line 425, I now have:

knobValue[i]++; // reverse direction

This is in routine check_rotary_encoders() in the for() loop to "detect end of rotation". Search for "bugfix 20181225" - there shouldn't be any occurances in the file. Apparently, different hardware switches behave differently. After making the change, rebuild:

cd /opt/pidp11/src
./makeserver.sh

I have not had the problem you describe about "one click moves randomly". I suppose it is possible that a Pi3 is too slow when combined with the new OS, but that is just a wild guess.

The "pdp" command (/opt/pidp11/etc/pdp.sh) should connect to the running simulation without clobbering anything.

Steve

[terry-...@glaver.org]

Does anyone have a more recently updated 2.11BSD disk image (preferably otherwise unmodified, aside from having the updates applied)?

If I don't get any replies with such an image, I'll do the updates starting at the patch level the image in the PiDP distribution is, and then send the updated image to Oscar so he can update the kits.

[Heinz-Bernd Eggenstein]

> Does anyone have a more recently updated 2.11BSD disk image (preferably otherwise unmodified, aside from having the updates applied)?

You should check:

https://github.com/chasecovello/211bsd-pidp11

Cheers

HB