File talk:9th floor techsquare.png

Additional comments by Tom Knight

This diagram is largely correct, but was not a snapshot in time. 1401 was gone before Multics 635 installation. 936/936A had not lisp machines until much later. 7090 was replaced by the 645 Multics machine. 908 had the Kludge PDP-7, and the AI PDP-1 was traded in for the PDP-6. The DM PDP-10 and the IMP were located near the DM PDP-6, toward what is labeled 1401. For those of you following along, synthetic biology was started in my lab in rooms 922/923. Source: https://twitter.com/TomKnightSynBio/status/1480629226990567428

I should do a diagram of what I can remember of the layout in my time. E.g. the IMPs were indeed on the outer wall under where it says '1401', but the DM PDP-6 was between them and the DM KA10. Jnc (talk) 12:01, 11 January 2022 (CET)

That would be good. Someone is making a 3D model of the AI PDP-6/10 room (see http://aap.papnet.eu/pub/pdp/10/pdp6_unity2.PNG and http://aap.papnet.eu/pub/pdp/10/pdp6_unity4.PNG), and possibly the entire floor eventually. Additional details would be helpful. Larsbrinkhoff (talk) 17:27, 23 January 2022 (CET)

Location of MC

Trying to get a better fix of MC. There's a photo here: https://donhopkins.com/home/catalog/images/mc-console.jpg There seems to be a corner right behind the CPU. Is that room 936? Larsbrinkhoff (talk) 17:27, 23 January 2022 (CET)

No; like I said in File talk:Mit-mc.jpg, "A wall, parallel to the building's long axis, was built roughly between the two pillars above where it says '1401' in red [on the File:9th_floor_techsquare.png plan]. MC was in the space between the group of 4 pillars [in that plan, where it says 'Multics']". The thing you can see behind the CPU might be one of those pillars.

On the other side of that wall, which is behind the RP04's you can see a tiny bit of in photo, in the gap between the CPU and the RH10, is where MIT-XX was eventually installed. See also the notes at Talk:Incompatible_Timesharing_System#MC configuration.

If you look at my File:MC-KL_Layout.jpg diagram, the photo above is taken from the middle, pointing towards the RH10. You can see a corner of the Ampex on the right-hand edge of the photo.

Note: my diagram has a couple of minor scaling errors:

• The CPU was actually further out, closer to the Ampex, than in the diagram (i.e. the row of Mx10 memories, with the RH10 and DF10 at the end, extend further to the left than in that drawing);
• The Ampex was closer to the CPU, more about in the center of the row of Mx10's (i.e. further to the left than in the diagram).

Should I update the diagram to fix those errors? Jnc (talk) 22:09, 23 January 2022 (CET)

New, fixed version uploaded. Jnc (talk) 02:30, 15 February 2022 (CET)

Comments from Brian Silverman

Where the floor plan has room 919 and 920 there was an open space. The XGP-11 and TV-11 was there. Hanging from the ceiling was the now unused Marvin arm. The CONS was also in this area.

The AI PDP-10 was closer to the outer wall (down in the picture), and the moby memory was in front of it (up).

Larsbrinkhoff (talk) 17:52, 13 February 2022‎

The XGP and the XGP-11, yes. The TV-11 was, IIRC, up in the corner: about where the little room under 916C was. (I think everything except 916A&B and 917 was gone by then.)

The CONS machine was, I'm pretty sure, in the same room as CHEOPS: 904 or 906 (I forget exactly which). The first CADR was in there, initially at least, too. (I dunno if it ever moved; it might have.)

The robot backplane wirewrap checker for the 'production' CADRs was on the raised floor about where the Marvin arm had been; where 920 used to be.

I'm fairly astonished that there are no photos of that entire area, at any point. These days there'd be a bazillion. Jnc (talk) 02:03, 14 February 2022 (CET)

Thanks for this, also for the new MC diagram! There are some photos and I have put them here: https://github.com/larsbrinkhoff/its-archives/tree/master/photos

Many photos are of the PDP-6. I have tried to arrange them a timeline: http://its.pdp10.se/pdp6-timeline/

Larsbrinkhoff (talk) 09:42, 15 February 2022 (CET)

What's astonishing, looking at these, is how little they show. For instance, look at this MC/CADR photo; I can't really tell where it was taken (one can't see enough of the background) - about all one can really glean from it is that it reminded me that all CADRs were always paired with a floor-standing Trident drive (a T-80, I thought; but looking at that pack, it looks like maybe it was a T-300 - at least, this one - maybe others had T-80's).

Without looking at every photo in the collection, here are some comments on notable ones:

• moses-winston-ka10 - the low resolution of this one (a problem with almost all of them) limits its utility, but that's probably ML; behind Winston are the two CPU bays, and then, to their left, are (I think) the pager, and then maybe some of the MD10's? Very hard to see clearly, that could be the tape drive (behind the left side of Moses' head).
• random-9th is potentially rich, but let down by the low resolution. I wonder if, somewhere, some MIT archive has the original photos used to produce this brochure; if so, that would be a tremendous resource. The bottom photo appears to show ML (on the left) and then DM (in the distance); but again, the resolution is so low it's not very useful.
• random-9th-2 - I'm not even sure which machine that is, at the bottom; the 2 bays at the far end are possibly a KA10 CPU (the two white-outlined panels at the bottom of the bays are, IIRC, air intakes for cooling - maybe a DEC advertising shot of a KA10 will show them).

Still, vey thin gruel... Jnc (talk) 12:34, 15 February 2022 (CET)