PDP-6: Updates to run ITS 138 about sims HOT 9 CLOSED

Devices 70 and 750 for GE Datanet 760 input and output, respectively. The output device has a PI channel. Input and output is expected to be 7-bit characters to some sort of controller. The controller has four consoles attached, for which there already is an emulator.

Details about the I/O protocol will need to be reverse engineered from ITS 138 source code.

from sims.

Modifications to the 120 TTY device, as described in AI memo 105.

from sims.

There's probably a MAR register, likely similar in functionality to the MAR of the ITS pager.

from sims.

How are UUOs treated on the stock PDP-6? AI memo 161 says their PDP-6 was modified to have UUOs 001-037 and 050-077 in user mode go directly to relocated location 41.

from sims.

One-proceed to single step in timesharing. I don't know yet how it works.

from sims.

Strike out MAR and one-proceed. I don't see them in the listing.

from sims.

I have almost completed a "GE" device, see issue #315.

To test ITS 138, get and build these branches:

• https://github.com/larsbrinkhoff/ka10-simh/tree/lars/1967 (possibly omit the TTY commit).
• https://github.com/PDP-6/ITS-138/tree/lars/simh
• https://github.com/aap/vt05/tree/master

I'm building on Linux. For Windows, YMMV.

Go to the "simh" directory in ITS-138. Edit the start.sh and its138.do files to your liking. Run start.sh. You should get a GE console window. There's some text about telnet, but as soon as ITS boots it sends a ^L which clears the display. If you type ^Z, ITS will try to load UT2: @ HACTRN.

Typing ^Z to the console TTY should also work, but maybe my modifications broke it.

FYI @aap

from sims.

At this point, ITS reads block 100 from the tape, which is the directory. It then seeks back to load @ HACTRN starting from block 10. This doesn't seem to go quite right. I put breakpoints at USTCD, USTCD1, and USTCD2. ITS gets to USTCD which means it's trying to start a new user HACTRN. It also enters USTCD1 which is a loop reading the data in an SBLK file. It does not go to USTCD2 which is where it jumps to the program starting address.

from sims.

The GE device has been merged. The TTY modifications are not yet complete, and they don't seem to be important for running ITS anyway. The MAR and one-proceed are not in use with ITS 138.

from sims.