PDP-1 - Revision history

Jnc: /* External links */ +A Time-sharing Debugging System for a Small Computer

2025-09-30T15:51:51Z

‎External links: +A Time-sharing Debugging System for a Small Computer

Jnc: Add PDP-1D info

2025-07-15T22:48:30Z

Add PDP-1D info

Jnc: /* See also */ +PDP-1-X

2025-04-07T15:38:05Z

‎See also: +PDP-1-X

Jnc: RLE PDP-1 was the nucleus for early hacker culture at MIT

2024-02-27T21:18:20Z

RLE PDP-1 was the nucleus for early hacker culture at MIT

Jnc: /* External links */ +MIT-RLE PDP-1 material at Bitsavers

2024-02-27T21:12:28Z

‎External links: +MIT-RLE PDP-1 material at Bitsavers

Larsbrinkhoff: 18-bit cat.

2023-07-11T11:38:47Z

18-bit cat.

Jnc: /* External links */ typo

2023-06-18T22:44:17Z

‎External links: typo

Jnc: /* External links */ +PDP-1 Restoration Project

2023-06-16T12:55:13Z

‎External links: +PDP-1 Restoration Project

Jnc: /* External links */ +manuals

2022-08-06T21:18:22Z

‎External links: +manuals

Jnc: /* External links */ actually PDP-1 material starts before the TX0/TX2 stuff

2021-12-08T23:56:49Z

‎External links: actually PDP-1 material starts before the TX0/TX2 stuff

@@ Line 72: / Line 72: @@
 ** [https://www.computerhistory.org/pdp-1/origins-of-the-pdp-1/ Origins of the PDP-1]
 ** [https://www.computerhistory.org/pdp-1/restoration/ Restoration]
 * C. Gordon Bell, Gerald Butler, Robert Gray, John E. Mcnamara, Donald Vonada, and Ronald Wilson, [http://gordonbell.azurewebsites.net/Computer_Engineering/00000145.htm The PDP-1 and Other 18-Bit Computers], in C. Gordon Bell, J. Craig Mudge, John. E. McNamara, ''Computer Engineering: A DEC View of Hardware Systems Design'', Digital Press, Bedford, 1978
-* [https://www.masswerk.at/spacewar/inside/pdp1-instructions.html Inside Spacewar! (Supplement) - DEC PDP-1 Instruction List] - includes the instructions added in the PDP-1/D
+* J. McCarthy, S. Boilen, E. Fredkin, J. C. R. Licklider, [https://dl.acm.org/doi/10.1145/1461551.1461559 ''A Time-sharing Debugging System for a Small Computer''], [[AFIPS]], Spring Joint Computer Conference, 1963, pp. 51-57
 {{Nav DEC}}

@@ Line 14: / Line 14: @@
 | price = US$120K (4KW system)
 }}
+The '''PDP-1''' was the first [[computer]] built by [[Digital Equipment Corporation]]. It was an 18-bit machine; a [[load-store architecture]], with a single [[accumulator]]. Around 50 were built.
 The basic PDP-1 included 4KW of [[core memory|core]] [[main memory]]; an optional Type 15 Memory Extension Control allowed (via [[bank switching]]) the addition of up to fifteen additional 4KW Type 12 Core Memory Modules, for a maximum total of 64KW.
-The later optional Type 10 Automatic Multiply and Divide added [[instruction]]s to perform multiplication and division at high speed in hardware (previously, they had been done in software [[subroutine]]s, albeit with support from specialized instructions).
+The later optional Type 10 Automatic Multiply and Divide added [[instruction]]s to perform multiplication and division at high speed in [[hardware]] (previously, they had been done in [[software]] [[subroutine]]s, albeit with support from specialized instructions).
-Standard peripherals included a [[paper tape]] reader and punch, and a [[terminal]]. Optional peripherals included [[graphics]] [[display]]s, a [[light pen]], [[line printer]], [[punched card]] reader and punch, and [[magnetic tape]] [[device controller|controller]] and [[magnetic tape drive|drives]]. <!-- Two different [[magnetic storage|magnetic]] [[drum]] [[secondary storage]] systems (xx) -->
+Standard [[peripheral]]s included a [[paper tape]] reader and punch, and a [[terminal]]. Optional peripherals included [[graphics]] [[display]]s, a [[light pen]], [[line printer]], [[punched card]] reader and punch, and [[magnetic tape]] [[device controller|controller]] and [[magnetic tape drive|drives]]. <!-- Two different [[magnetic storage|magnetic]] [[drum]] [[secondary storage]] systems (xx) -->
-A PDP-1 at [[Massachusetts Institute of Technology|MIT]]'s [[Research Laboratory of Electronics|RLE]] served as the nucleus for early [[hacker]] culture at MIT.
+A PDP-1 at [[Massachusetts Institute of Technology|MIT]]'s [[Research Laboratory of Electronics|RLE]] served as the nucleus for early [[hacker]] culture at MIT, including for the first [[video game]], [[Spacewar!]]. The PDP-1/D at [[Bolt, Beranek, and Newman|BBN]] was much used in the early [[ARPANET]] work; both for software development, and as the Network Control Center's first machine.
 ==Technical details==
@@ Line 29: / Line 28: @@
 The instruction format consisted of a 5-bit basic operation code, a 1-bit indirect address bit, and a 12-bit memory address. If the indirect address bit was set in the indirect word, the indirection process repeated. <!-- The augmented instructions all share an operation code. In them, the address field is not used for an address; instead, each bit of the field can specify a separate operation, and generally more than one bit can be set at a time (except for most of the [[skip]] operations). --> The [[Program Counter]] is also 12 bits long.
-The PDP-1 used [[one's complement]] arithmetic.
+The base PDP-1 used [[one's complement]] arithmetic.
-They were built out of DEC's [[System Module|System Building Blocks]]
+The PDP-1/D was a semi-custom machine, and the two that were known to be sold were somewhat different from each other. The basic difference from the regular PDP-1/C was hardware support for [[time-sharing]]; support for [[two's complement]] arithmetic was also added.
 {{semi-stub}}
@@ Line 44: / Line 62: @@
 * [http://www.bitsavers.org/pdf/mit/rle_pdp1/ MIT-RLE PDP-1] - material at Bitsavers
 * [https://www.computerhistory.org/pdp-1/_media/pdf/DEC.pdp_1.102664938.pdf PDP-1 and PDP-3 brochure]
 * [https://www.computerhistory.org/pdp-1/_media/pdf/DEC.pdp_1.pulse_height_anlayzer.1963.102664958.pdf A time-shared computer for real-time information processing], 1963
 * [https://gordonbell.azurewebsites.net/Digital/PDP%201%20Manual%201960.pdf PDP-1 Manual, 1960]
 * [https://gordonbell.azurewebsites.net/Digital/PDP%201%20Manual%201961.pdf PDP-1 Manual, 1961]
 * [https://gordonbell.azurewebsites.net/Digital/F25_PDP1_IO.pdf PDP-1 Manual for I/O] (F-25)
 * [https://www.computerhistory.org/pdp-1/ PDP-1 Restoration Project] - at the [[Computer History Museum|CHM]]
 ** [https://www.computerhistory.org/pdp-1/origins-of-the-pdp-1/ Origins of the PDP-1]
 ** [https://www.computerhistory.org/pdp-1/restoration/ Restoration]
 * C. Gordon Bell, Gerald Butler, Robert Gray, John E. Mcnamara, Donald Vonada, and Ronald Wilson, [http://gordonbell.azurewebsites.net/Computer_Engineering/00000145.htm The PDP-1 and Other 18-Bit Computers], in C. Gordon Bell, J. Craig Mudge, John. E. McNamara, ''Computer Engineering: A DEC View of Hardware Systems Design'', Digital Press, Bedford, 1978
 {{Nav DEC}}

← Older revision		Revision as of 15:38, 7 April 2025
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	{{semi-stub}}		{{semi-stub}}
		+
		+	==See also==
		+
		+	* [[PDP-1-X]]

	==External links==		==External links==

@@ Line 22: / Line 22: @@
 Standard peripherals included a [[paper tape]] reader and punch, and a [[terminal]]. Optional peripherals included [[graphics]] [[display]]s, a [[light pen]], [[line printer]], [[punched card]] reader and punch, and [[magnetic tape]] [[device controller|controller]] and [[magnetic tape drive|drives]]. <!-- Two different [[magnetic storage|magnetic]] [[drum]] [[secondary storage]] systems (xx) -->
 ==Technical details==
@@ Line 36: / Line 38: @@
 * [http://www.bitsavers.org/pdf/dec/pdp1 PDP-1] - Original PDP-1 documents at [[Bitsavers]]
-* [http://www.bitsavers.org/pdf/mit/rle_pdp1/ - MIT-RLE PDP-1 material at Bitsavers
+* [http://www.bitsavers.org/pdf/mit/rle_pdp1/ MIT-RLE PDP-1] - material at Bitsavers
 * [https://www.computerhistory.org/pdp-1/_media/pdf/DEC.pdp_1.102664938.pdf PDP-1 and PDP-3 brochure]
 * [https://www.computerhistory.org/pdp-1/_media/pdf/DEC.pdp_1.pulse_height_anlayzer.1963.102664958.pdf A time-shared computer for real-time information processing], 1963

@@ Line 36: / Line 36: @@
 * [http://www.bitsavers.org/pdf/dec/pdp1 PDP-1] - Original PDP-1 documents at [[Bitsavers]]
 * [https://www.computerhistory.org/pdp-1/_media/pdf/DEC.pdp_1.102664938.pdf PDP-1 and PDP-3 brochure]
 * [https://www.computerhistory.org/pdp-1/_media/pdf/DEC.pdp_1.pulse_height_anlayzer.1963.102664958.pdf A time-shared computer for real-time information processing], 1963

← Older revision		Revision as of 11:38, 11 July 2023
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	[[Category: DEC Systems]]		[[Category: DEC Systems]]
		+	[[Category: 18-bit Computers]]