On 12/27/17, Dave Horsfall <dave(a)horsfall.org> wrote: That may have been true in the 1960s, but by the mid-1970s IBM System/360/370 was no longer competitive in the educational market. Circa 1973, Boston College--a true Blue IBM shop with a System/370-145--wanted to provide time-sharing services to the student body. For less than the cost to upgrade the model 145 to a 158, they bought a PDP-11/70 and ran RSTS on it. Similarly Holy Cross (my alma mater) had outgrown their System/370-125 by 1976. For the price of an upgrade to a model 135, they could by a complete VAX-11/780 system for academic use and retain the S/370-125 exclusively for college admin purposes. The 11/780 was equivalent in compute power and memory capacity to a S/370-158, but for about 1/4 the cost. -Paul W.

On 12/27/17, Kevin Bowling <kevin.bowling(a)kev009.com> wrote: By the mid 1960s IBM had established a huge market presence and took advantage of it to reap large profit margins by not passing along the ever-decreasing manufacturing costs (corollary of Moore's law) to its customers. DEC, Data General, etc. were willing to accept lower profit margins. This allowed them to sell into new markets (e.g., small research groups) that IBM had priced themselves out of, and from that base to make inroads into the general business marketplace. Not really, in my experience and from my perspective both as a DEC customer and as a DEC development engineer. DEC's original customer base were experienced research engineers and scientists who knew what they wanted and didn't have to be sold to. Ken Olsen grew up simply taking customer orders, and he never understood or really supported marketing. Lack of marketing skill eventually caught up to DEC by the late 1980s and was a principal reason for its downfall. In the days of the PDP-11 and VAX, DEC also didn't provide the level of customer service, support, and hand-holding that IBM did (this was part of the reason why IBM systems were so expensive). Among IBM customers the saying was, "minicomputers aren't sold, they're abandoned". When our VAX arrived in 1978, we were appalled at DEC's inability to send on-site customer engineers to help us with software problems. Someone (Scott McNealy?) once said to survive a computer company has to be prepared to eat its own children. That is, to accept the faster, lower cost technology as it comes along and not to try to protect high profit margins on the older technology. Minicomputers ate the floor out from under mainframes, and IBM lost market dominance by attempting to protect the mainframe cost structure. PCs did the same thing to minicomputers in the early 1990s, and DEC repeated IBM's mistake by trying to defend against PCs instead of embracing them. -Paul W.

The PDP-8 and 11 were cheap and this allowed them to be used both in lab situations (I remember working with PDP-8's around 1975 at UofM in non engineering departments like psychological-pharmacology) and at the departmental level, in contrast to the central data centers. I cut my teeth on the PDP-11/45 (running UNIX) in the Electrical Engineering department. One of the Biomedical Engineering labs used an LSI-11 running miniunix followed by an 11/23 also running UNIX. I used PDP-11's in several locations in the Psych department and in the biomedical and opthomological departmetns at the Med School. All this typically by people they wouldn't let anywhere near the campus computing mainframes. The CS Department at the UofM taught a OS course (where students wrote one of their own) on a pair of 11's upstairs from the computer center. Amusingly, on the cloud subject, years later those PDP-11's were getting long in the tooth (and you had to share them single user between a large class). The computer center downstairs had installed several IBM VM/CMS systems. We offered to rewrite the course curriculum, very centered on the PDP-11, to allow them to teach it on VM (writing their own hosted OS under VM). Couldn't convince the faculty. Made too much sense.