Claude wrote (excerpted) An amazing software system for the time. Any of the Cyber 7x and 17x machines could run Plato, I believe, but I think that there were some special interfaces that were used to hook up those special terminals to the system's I/O subsystem. Oh, they're big all right. Back in the late 1970's, I used to be a systems operator at Tektronix, in Beaverton, Oregon. The Tektronix Scientific Computer Center had a a CDC Cyber 73. It was monsterous. First off, it had a cabinet about the size of a VAX 11/780 CPU that was nothing but the REFRIGERATION for the system. There was a series of pipes that ran through the system that provided the cooling. Next, was the massive motor/generator down in the basement of the building (the computer center was on the 4th floor of the building). The Cyber ran on 400Hz 3-phase. The motor/generator downstairs took 220V 3-phase and converted it to 400 cycle power. I never saw the motor/generator, but I was told that it was about the size of a semi-truck trailer. The power supply of the machine was another approx. 8 ft. tall, 4 ft. wide cabinet. The CPU itself was, as I recall, 6 bays, each of which was big enough, that when the outer doors were opened, and the internal bays containing the electronics were swung out, a man could fit inside. The bays were about 4 feet deep, 8 feet tall, and 6 to 7 feet wide. The machine was truly amazing. A 60-bit word main CPU, with ten PPU's (peripheral processing units) that performed interface to peripherals. I think (can't remember for sure) that it had 128K-words (each word 60 bits) of core memory. One of the 'peripherals' of the system was a Modcomp 16-bit minicomputer that handled all of the I/O to literally hundreds of async terminals all over the Tek campus. Characters were represented in 6 bits...called 'Display Code'. The Modcomp did all of the translation between ASCII and Display code for all of those terminals. The console of the system was glorious...a very large desk, with two round CRT displays that used vector graphics to paint the screen. There were a lot of fun graphics programs that could only run on the console...things like 'eyes' that would look around and blink, a great chess game, and a Snoopy vs. the Red Baron animation that was fun. The 73 had two 9-track and one 7-track magtape drive, a monster CDC chain-type line printer(that thing was FAST), a card reader, a card punch, and a big slew of those washing-machine-sized 10 or 12-platter removable disc drives (there must have been 14 or 16 of 'em, each holding something like 300 MB of 12-bit words. This system didn't run Plato. I learned about Plato from an engineer that worked at Tek who went to the University of Illinois, a place where a lot of Plato development work was done. The OS that ran on the system was called KRONOS. It was a multi-user multi-executive OS that did both interactive and batch processing. There were a number of RJE stations around the campus that had punch card readers and printers that users could submit their F77 (Fortran 77) and PASCAL jobs to remotely. Later, Tek brought in another big CDC machine, a Cyber 175, I believe. It wasn't quite as large as the 73, but still needed liquid cooling, most all of the logic in the 175 was ECL, and it ran fast and hot. The console wasn't nearly as impressive, one 'page' oriented CRT, but still vector. I think that the 175 had 20 PPU's versus the 10 of the Cyber 73, and of course, the main CPU was quite a bit faster than the old 73. Next to nil, I would guess. They were loaded with precious metals (gold!) and lots of good scrap metal too. The scrappers loved 'em. Even if you could find one in storage somewhere (it'd have to be a pretty good-sized warehouse!) it'd be a major operation just to move the machine. Plus, once you got it to your house, not likely you'd have any place to put it! Not the kind of machine you can set up out in the garage. Then...even if you had a place to put it, getting the 400Hz 208V is going to be a challenge...probably draws some massive load. Don't know what the current loading was Very hard to say. I know that University of Illinois did a lot with Plato...perhaps someone there has some old tapes laying around. Might not be able to read them anymore...early Cybers used 7-track magtape, at some ridiculously low bpi. I remember seeing an old show called "The 21st Century" sometime in the '70's that was hosted by Walter Cronkite. One show was on computers. They showed one of the plasma Plato terminals, with a child running a CAI (Computer Aided Instruction) program. Now, you've probably got a better time trying to find one of those old plasma terminals than you've got of finding a Cyber laying around somewhere. Thanks for the memories, Rick Bensene The Old Calculator Web Museum http://www.geocities.com/oldcalculators