From mboxrd@z Thu Jan 1 00:00:00 1970 From: paul.winalski@gmail.com (Paul Winalski) Date: Wed, 27 Dec 2017 18:44:07 -0500 Subject: [TUHS] Why did PDPs become so popular? In-Reply-To: References: <109152082.5216233.1514413535270.ref@mail.yahoo.com> <109152082.5216233.1514413535270@mail.yahoo.com> Message-ID: On 12/27/17, Dave Horsfall wrote: > On Wed, 27 Dec 2017, Dave Ritchie via TUHS wrote: > >> I think that steep educational discounts and equipment grants from >> Digital to major collages also had a major impact, as did the existence >> of DECUS that made a lot of software readily available. > > IBM practically gave away their kit to educational institutions too (and > made their money from the maintenance); there was no way that the > University of NSW e.g. could've afforded their 360/50 otherwise, 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.