1,289 discussions, 9,527 archived comments; pages no longer carry the comments themselves. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01YDRjtmAiNpo5mK5N3d7QwZ
107 lines
4.5 KiB
Markdown
107 lines
4.5 KiB
Markdown
---
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title: Digital Equipment Corporation PDP-8
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categories:
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- Computers
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types:
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- Professional Computer
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origins:
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- U.S.A.
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years:
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- '1965'
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params:
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name: PDP-8
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image: /media/museum/photos/dec_pdp8_system_1.jpg
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company: /companies/digital-equipment-corporation
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company_name: Digital Equipment Corporation
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specs:
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- label: NAME
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value: PDP-8
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- label: MANUFACTURER
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value: Digital Equipment Corporation
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- label: TYPE
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value: Professional Computer
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- label: ORIGIN
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value: U.S.A.
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- label: YEAR
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value: '1965'
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- label: END OF PRODUCTION
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value: '1980'
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- label: BUILT IN LANGUAGE
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value: None
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- label: KEYBOARD
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value: ASR-33 Teletype
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- label: CPU
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value: CPU was composed of 12 interlinked Register Boards
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- label: SPEED
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value: 1 MHz (0.5 MIPS)
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- label: RAM
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value: 4 K of 12 bit words
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- label: TEXT MODES
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value: Depending of the terminal used
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- label: SIZE / WEIGHT
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value: 48 (W) x 55 (D) x 84 (H) cm. / 150 Kgs.
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- label: I/O PORTS
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value: 110 Baud serial interface
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- label: BUILT IN MEDIA
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value: None
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- label: POWER SUPPLY
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value: Built-in 780 Watts power supply unit
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- label: PERIPHERALS
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value: Memory boards up to 32 Kwords
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- label: PRICE
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value: $18.000 (Basic version)
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tabs:
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- emulators
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- links
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forum_thread: 761
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emulators:
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- title: SIMH
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url: http://simh.trailing-edge.com/
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platform: Windows
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text: Windows emulator for a lot of mini computers. Sources are available so you can compile them for your own platform.
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- title: PDP-8/E
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url: http://www.bernhard-baehr.de/pdp8e/pdp8e.html
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platform: Apple
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text: emulator for the DEC PDP-8/E minicomputer running on the Apple Macintosh
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links:
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- title: Douglas W.Jones's DEC PDP8 Home Page
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url: http://www.cs.uiowa.edu/~jones/pdp8/
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text: Wow, tons of doc and info here !
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- title: More information about DEC PDP8 operating systems
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url: http://www.faqs.org/faqs/dec-faq/pdp8/section-10.html
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text: With PDP8 FAQ as well
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- title: PDP-8 Technology Before The Millennium
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url: http://www.pdp8.com/
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text: PDP-8 Restoration Notes
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- title: Yet Another PDP-8 Web Site
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url: http://www.pdp8.net/
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text: Lot of information and pictures
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related:
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- /museum/digital-equipment-corporation-vt78
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oc_id: 780
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source:
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url: https://web.archive.org/web/20230608091007/http://www.old-computers.com/museum/computer.asp?c=780
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date: '2023-06-08'
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---
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The PDP-8 was the first sucessful commercial minicomputer, produced by DEC in the 60s, the first real minicomputer, and the first computer costing less than $20,000.
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By late 1973 to 77, the PDP-8 family was the best selling computer in the world. The basic version could sit on a desktop rather than requiring cumbersome racks well known at the time. This compact size caused it to become a popular system in scientific laboratories.
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The machine had a now quite strange 12-bit word and four thousand 12-bit words of magnetic core memory. The first model was built without any Integrated circuit - thus no microprocessor - but with discrete transistors mounted on numerous small printed circuit boards called 'flip chips' that were inserted on two backplanes mounted vertically. Both table-top and rack-mount models were available, but adding additional memory required a rack.
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CPU was composed of 12 interlinked Register Boards each operating on one bit slice of the 12 bit word and containing an Adder function together with all the major registers - MB, MA, AC, PC. Speed a little less than 1MHz.
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The instructions set of the PDP-8 was very limited, only eight basic instructions encoded by the three left bits of each 12-bit word, and one register, the accumulator: However, the PDP-8 could be programmed to do almost anything. It just took longer (sometimes very longer!) to execute programs.
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A 110 baud current loop teletype interface allowed an ASR 33 Teletype to be connected, serving as a console as well as a storage device by means of the built-in papertape puncher and reader.
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There were numerous variations of the original model over the years, among them:\
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1966: **PDP-8/S** - minimum price but slow memory serial logic design\
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1968: **PDP-8/I** - first version with integrated circuits\
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1970: **PDP-8/E** - New bus structure design called Omnibus\
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1975: **PDP-8/A** - Allowed OEMs choice of memory type and quantity
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All together, about 50,000 PDP-8 series computers were sold, as well as numerous clones made USA, Asia and East European countries.\
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In 2000 year, there were still a few PDP8's in operation, mainly in third-world countries.
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