I wrote: large-scale "special" people were allowed ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^ To which, Rich A. replied: (Thanks, Neil!) jobs, unlike the jobs for which the small systems programming on mainframes was special purpose, batch oriented, data the rest was high intensity engineering (where at this level >even physics is engineering) which needed lots of data handling for short runs. Yeah...I can agree with that. But, part of the talk was about getting "up close" with the computer, at a personal level - hands-on. The glass-walled room machines weren't that way, and thus weren't considered "personal computers", for just the reason you mentioned -- the work typically done on them was of a different class of work that didn't require any kind of hands-on activity with the machine (except for the operators, who loaded up the jobs, managed the tapes, and gathered the printouts). The discussion had gone from talk about the IBM 709/709X computers, which were more "glass room" type machines, to discussion about personal computers. I suffered some angst over the discussion of machines like Apple IIs or even Altair 8800's as the first personal computers, when in fact, the general term applied to computers that came long before these machines. Perhaps the glass-room meme isn't so much bogus, as it is a sign of the cultural times. In those days, the big machines were very expensive, and required a lot of support -- that meant special power, air conditioning, raised floors, and highly-trained people. The "management" of these big machine installations had a lot at stake...and as such, they were very protective of their machines, which is most of the reason they were encased in glass (they needed to be glass to be able to show them off without letting people in...in the days, big computer installations were class icons). It wasn't really so much that the work that the consumers (I wouldn't use the word "users" to describe them, because they were never really "using" the machine) of the results of the machines didn't need to have access to the machines...it was more because the management only wanted those who had all the necessary training and knowledge operating the machines to assure the maximum amount of productivity for their multi-million dollar investments to gain the best return on that investment, as well as safety for these "delicate" machines. As for the PDP-11, it was indeed a significant omission. Honestly, I ran out of time. I missed the PB 250, which certainly should have been on the list, and the PDP-11...and I'm sure that there are quite a number of other machines that were missed. Compiling a full list of this class of machines, even during this somewhat limited time period, would be a daunting process. There were many companies that popped up in the 1960s, along with those from established computer makers, that marketed small computers that were generally intended to be used on a single-user basis, by individuals. Examples off the top of my head are Computer Automation (PDC-808), Smith Corona/Marchant SCM 7816, 3M (yes, the adhesive people) 2018, Control Data 160/160-A, Digital Equipment PDP-1, HP 2100-series, Data Acquisition Corp. DAC-512.....it could go on and on. I was writing my message as I was getting ready to head off to work, and had to stop before I ended up being late. -Rick --- Rick Bensene The Old Calculator Museum http://oldcalculatormuseum.com