PDP-6

[larsbrinkhoff]

I believe the AI PDP-6 was connected to the KA10 as a slave CPU.

It may be unrealistic to try to resurrect this configuration, but we can make notes here.

[larsbrinkhoff]

From references in SYSDOC; it seems it was possible to read/write PDP-6 memory, and load/start jobs.

• <JOB> 400376 specifies the pdp6.
• LOAD .CALL The default is ... 20,,37777 when loading the PDP6.
• OPEN .CALL A jname of PDP6 or PDP10 opens up the PDP-6 as a "job". (PDP10 as a jname goes back to the days when the PDP-6 ran ITS and the PDP-10 was the auxiliary processor!).
• .UPC .USET %PCSPC==1000 - Unused. (A PDP6 feature)
• .DCLOSE UUO In the case of the 340, the display is made available to the pdp-6.
• .IPDP UUO intererupt PDP-6
• .RD710 UUO Device 710 used to be a kind of clock on the PDP-6.
• .RD760 and .WR760 UUOs Device 760 of the PDP-6 used to be used for temporary direct sense hookups.

[larsbrinkhoff]

Programs mentioning the PDP-6:

• SYSEN1; DDT 1546
• SYSEN2; TENLOD 18, see TENLOD #276.
• SYSEN2; FED 134 - Font editor, see FED - font editor #289.
• SYSEN2; LD10 61 - Lisp display slave, see Lisp display slave #651.
• SYSEN2; BIG 160 - Music?
• RG; CHESS2 614 - Chess, see CHESS #266.
• Spacewar, see Spacewar - game #281.

Standalone binaries using PDP-6 Microtape:

• TECO
• STINK

[larsbrinkhoff]

SYSDOC; ITS HISTRY says

[1115] 5/27/78
The following items deleted from the AI system (softwarily):
340, DSD, OMX, IMX, N D/A, PDP6, H CLK

I suppose this means the software for accessing the PDP-6 was removed in 1978.

[larsbrinkhoff]

We have Spacewar source code from 1976 with support for the PDP-6, so I suppose it was running then.

[larsbrinkhoff]

AI Memo 118 describes how to use MACDMP to load programs from tape into the PDP-6.

@aap We still have MACDMP, although it fell by the wayside. It spawned DSKDMP which is is now used to boot ITS from disk.

[larsbrinkhoff]

Noel Chiappa:

The paging box built for the KA10 had the PDP-6's memory space as one of its 4 'mobys' (the other three being 2 for AI's memory, and one for the Rubin 10-11 interface).

[ericsoderstrom]

I asked rms if he knew where to find old versions of ITS. He said he didn't. Dunno if there would be anymore likely than him to know where to find it, if it does still exist somewhere.

[larsbrinkhoff]

@ericsoderstrom Thank you. We're in touch with Richard Greenblatt, which is one of the authors of the first versions of ITS. There are also some people at MIT working on preserving their old backup tapes.

[larsbrinkhoff]

PDP-6 and 10 devices:

[larsbrinkhoff]

TECO6, MIDAS 6, and PDP-6 MACDMP sources are now in the ITS vault.

Standalone TECO and STINK binaries are installed in the ITS build.

[larsbrinkhoff]

Shared memory to PDP-6 works: #1141.

[larsbrinkhoff]

The PDP-6 is now a fully integrated part of the emulator suite. Though it takes some expertise to operate it. It supports most interesting devices:

• Core memory shared with PDP-10
• Type 340 display
• Color scope
• Spacewar consoles, old (724) and new (420)
• Playing music from memory indicators

[larsbrinkhoff]

From HW memo 1.