gillies@m.cs.uiuc.edu (01/24/89)
/* Written 6:23 pm Jan 19, 1989 by marc@hpfcdc.HP.COM in m.cs.uiuc.edu:comp.os.misc */ /* ---------- "Re: OS design driven by architectur" ---------- */ / hpfcdc:comp.os.misc / bauer@loligo.cc.fsu.edu (Jeff Bauer) / 2:49 pm Jan 18, 1989 / >>I understand it that when Don Bitzer at U of Ill. looked for CPU >>horsepower in the early 60's for PLATO IV (the current version of >>PLATO that exists on the Cybers) Control Data gear was pretty >>much the only choice... > >Maybe so, but I'll bet a lot of that had to do with TUTOR, "the official >arcane programming lanaguage of the Super Bowl (as well as PLATO)" which kind >of assumes that the natural wordsize is 60 bits. Or does PLATO IV predate >TUTOR? What is this discussion of PLATO about? I believe that PLATO I ran on a CDC 1600 or something like that. And it worked on a regular terminal, before Bitzer had invented the plasma display. The goal of PLATO has always been the bottom line: Delivering educational software to students at minimal cost. The system is terribly inelegant, because the language is designed to do EVERYTHING for you. Thus, nearly everything has a "command" to do it. You can draw fancy graphs on the screen with just 7-8 commands. You can do *VERY* sophisticated answer parsing/judging/pattern matching with spelling correction in just 10 TUTOR commands. The language is made for teachers, not programming jocks. Hence, there are about 500 commands. The language began when Fortran was the rage, before we understood what a compiler was, and structured programming was added in the late 1970's. The system is monster because the underlying assumptions have been violated. Computers are cheap. PLATO is meant to deliver 10 thousand instructions per second at a reasonable 1965 connect cost ($2-$10/hr). Today, you can get a 1 MIP (=1000 TIPS) cpu for $1000, so the system seems arcane. But then again, there are 12,000 hours of instructional available. Even MIT's Athena project won't match that in the next decade. So the system survives. Don Gillies {uiucdcs!gillies} U of Illinois