Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uwm.edu!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!cica!iuvax!pur-ee!mentor.cc.purdue.edu!gis From: gis@mentor.cc.purdue.edu (Brian L. Stuart) Newsgroups: alt.folklore.computers Subject: Re: Y VAX? [was : TECO on a DEC-System 10] Message-ID: <6551@mentor.cc.purdue.edu> Date: 19 Jan 90 19:34:49 GMT References: <153.UUL1.3#5131@mvac23.UUCP> <457@ns-mx.uiowa.edu> Reply-To: gis@mentor.cc.purdue.edu (Brian L. Stuart) Organization: Purdue University Lines: 85 In article <457@ns-mx.uiowa.edu> jones@pyrite.cs.uiowa.edu (Douglas W. Jones,201H MLH,3193350740,3193382879) writes: > [stuff already amply followed up] > Would someone from DEC please post the definitive family tree of the PDP-11 > family and hang the VAX from it correctly? Well, I'm not affiliated with DEC so I can't call this definitive, but it comes from C.G. Bell, et al's "Computer Engineering" so I consider it pretty reliable. By the way, you asked for it (well just the PDP-11 part) so here goes.... Year 18-bitters 12-bitters 16-bitters 36-bitters 1960 PDP-1 ------------------------------------------------------- | \ 1962 PDP-4 <--- LINC -------- \ 1963 | PDP-5 \ \ | 1964 PDP-7 | \ \ PDP-6 1965 | PDP-8 --\ | \ | 1966 | PDP-8/S LINC-8 | | 1967 | | | | KA10 1968 PDP-9 PDP-8/I,L | | | 1969 | | PDP-12 | | 1970 PDP-15 | PDP-14 PDP-11(/20) | 1971 | PDP-8/E / | \ | 1972 PDP-15/76 PDP-8/M - PDP-11/05 | PDP-11/45 -- KI10 1973 | / | PDP-11/40 | \ | | / | | | \ | 1975 PDP-8/A PDP-11/03 PDP-11/04 | | PDP-11/70 KL10 1976 | PDP-11/34 | PDP-11/55 | KL20 1977 VT78 | PDP-11/60 | 1978 PDP-11/34C VAX-11/780 A few notes: 1) The book was copyrighted 1978 so none of the later machines are mentioned, including 11/23, 11/24, 11/44, 11/73, 11/84 and later VAXen. 2) It's not really completely accurate to hang the VAX off of the 11/70, but: "As the PDP-11/70 design progressed, it was realized that for some large applications there would soon be a bad mismatch between the 64-Kbyte name space and the 4-Mbyte memory space."... "Thus, in 1974, architectural work began on extending the virtual address space of the PDP-11. Several proposals were made."... [The PDP-11/72 and/or PDP-11/74 that others have mentioned may be among these.] "In April 1975, work on a 32-bit architecture was started on VAX-11, with the goal of building a machine which was culturally compatible with PDP-11. The initial group, called VAXA, consisted of Gordon Bell, Peter Conklin, Dave Cutler, Bill Demmer, Tom Hastings, Richy Lary, Dave Rodgers, Stever Rothman, and Bill Strecker as the principle architect." [from Bell, et al., quoted without permission] While the VAX is always included in the PDP-11 family, I think that there are some good arguments for it being its own family, especially since they no longer include the PDP-11 compatibility mode. What do you think? 3) The PDP-11/03 is also known as the LSI-11 which was later updated to the LSI-11/2. (Technically it uses the LSI-11 processor and the system is known as the PDP-11/03). 4) It is interesting to note that the most successful family (the 11s) is the only family that wasn't really ancestrally related to any preceding family, but was done from scratch applying lessons learned from all others. (The original LINC was designed at MIT and DECs LINCs were based on it.) 5) The K?10 and KL20 processors were used in the DECSystem10 and DECSystem20 models and were sometimes referred to as the PDP-10. This is one area of DEC lore that I'm not real clear on. Could someone help add the details here? 6) The astute (and patient) reader will notice some missing machines: the PDP-2, PDP-3 and PDP-13. The PDP-2 was a number reserved for as 24 bit machine that was never build or, as far as I know, designed. The PDP-3 was designed as a 36 bit machine, but DEC never built it. but: "In 1960 a customer (Scientific Engineering Institute, Waltham, Massachusetts) built a PDP-3. It was later dismantled and given to M.I.T.; as of 1974, it was up and running in Oregon." As for the PDP-13? Triskaidekaphobia perhaps? Does anyone else know the story on this one? Ok, time for a little trivia (as if most of this weren't already). Now, no good computer information would be complete unless it involved 16 machines. So who remembers or knows about the PDP-16? Hint: it was fundamentally different from the PDPs 1-15. Brian L. Stuart Department of Computer Science Purdue University