Programmed Data Processor model 10.The series of mainframes from DEC that made time-sharing real. It looms large in hacker folklore because of its adoption in the mid-1970s by many university computing facilities and research labs, including the MIT AI Lab, Stanford, and CMU. Some aspects of the instruction set (most notably the bit-field instructions) are still considered unsurpassed. The PDP-10 was eventually eclipsed by the VAX machines (descendants of the PDP-11) when DEC recognised that the PDP-10 and VAX product lines were competing with each other and decided to concentrate its software development effort on the more profitable VAX. The machine was finally dropped from DEC's line in 1983, following the failure of the Jupiter Project at DEC to build a viable new model. (Some attempts by other companies to market clones came to nothing; see Foonly and Mars.) This event spelled the doom of ITS and the technical cultures that had spawned the original Jargon File, but by mid-1991 it had become something of a badge of honourable old-timerhood among hackers to have cut one's teeth on a PDP-10. See TOPS-10, AOS, BLT, DDT, DPB, EXCH, HAKMEM, JFCL, LDB, pop, push. alt.sys.pdp10 [Was the PDP-10 a mini or a mainframe?]
Last updated: 2001-01-05
PDP-11Programmed Data Processor model 11. A series of minicomputers based on an instruction set designed by C. Gordon Bell at DEC in the early 1970s (late 60s?). The PDP-11 family, which came after, but was not derived from, the PDP-10, was the most successful computer of its time until it was itself succeeded by the VAX. Models included the 11/23 and 11/24 (based on the F11 chipset); 11/44, 11/04, 11/34, 11/05, 11/10, 11/15, 11/20, 11/35, 11/40, 11/45, 11/70, 11/60 (MSI and SSI); LSI-11/2 and LSI-11 (LSI-11 chipset). In addition there were the 11/8x (J11 chipset) and SBC-11/21 (T11 chip) and then there was compatibility mode in the early VAX processors. The B and C languages were both used initially to implement Unix on the PDP-11. The microprocessor design tradition owes a heavy debt to the PDP-11 instruction set. See also SEX.
Last updated: 1994-12-21