Difference between revisions of "PDP-5"

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Predecessor to the [[PDP-8]].
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{{Infobox Machine
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| name = PDP-5
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| manufacturer = [[Digital Equipment Corporation]]
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| year introduced = September, 1963
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| form factor = [[minicomputer]]
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| word size = 12 bits
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| physical address = 15 bits (with Memory Extension Control; 32K words)
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| virtual address = 12 bits (direct), 15 bits (extended)
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| logic type = [[transistor]] [[System Module]]s
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<!--| design type = -->
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| instruction speed = 18 μsec (addition)<br>30 μsec (subtraction)
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| memory speed = 6 μsec ([[cycle time]])
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| predecessor = none
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| successor = [[PDP-8]]
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| price = US$25.8K (CPU and 4KW of memory)
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<!--| image = .jpeg
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| caption = A PDP-5 -->
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}}
  
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The '''PDP-5''' was [[Digital Equipment Corporation|DEC]]'s first 12-bit computer, the predecessor to the [[PDP-8]]; in some sense, it was DEC's first [[minicomputer]] (although the -5 pre-dated the creation of that term). Like the -8, it was a [[load-store architecture]]; its [[instruction set]] was very similar to that of the -8. A Type 154 Memory Extension Control unit was added later, to support [[bank switching]], and thus allow the use of more than 4KW of [[main memory]].
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It was constructed out of the standard modules created for the [[PDP-4]]. It was built using the [[bit-slice]] concept, where one bit of all the [[register]]s and the [[data path]]s between them was implemented on a single [[printed circuit board|PCB]]; a number of these boards (equal to the [[word]] length of the machine) formed the [[Central Processing Unit|CPU]]. To minimize the initial basic cost, it had an [[input/output|I/O]] [[bus]], rather than the radial links from the CPU to individual [[peripheral]]s used in all earlier DEC machines, such as the 18-bit machines like the [[PDP-1]].
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{{semi-stub}}
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==External links==
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* [http://www.bitsavers.org/pdf/dec/pdp5/ PDP-5] - documentation at [[Bitsavers]]
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* [https://gordonbell.azurewebsites.net/Digital/PDP%205%20Manual%201964.pdf PDP-5 Manual] <!--
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http://highgate.comm.sfu.ca/pdp8/off-topic/PDP5Handbook.pdf - another copy -->
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* [http://s3data.computerhistory.org/brochures/dec.pdp-5.1964.102646094.pdf Programmed Data Processor-5] - marketing brochure from DEC
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* [[C. Gordon Bell]] and John E. McNamara, [http://gordonbell.azurewebsites.net/Computer_Engineering/00000200.htm The PDP-8 and Other 12-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
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{{Nav DEC}}
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[[Category: DEC Systems]]
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[[Category: 12-bit Computers]]

Latest revision as of 19:03, 7 February 2024


PDP-5
Manufacturer: Digital Equipment Corporation
Year Introduced: September, 1963
Form Factor: minicomputer
Word Size: 12 bits
Logic Type: transistor System Modules
Instruction Speed: 18 μsec (addition)
30 μsec (subtraction)
Memory Speed: 6 μsec (cycle time)
Physical Address Size: 15 bits (with Memory Extension Control; 32K words)
Virtual Address Size: 12 bits (direct), 15 bits (extended)
Predecessor(s): none
Successor(s): PDP-8
Price: US$25.8K (CPU and 4KW of memory)


The PDP-5 was DEC's first 12-bit computer, the predecessor to the PDP-8; in some sense, it was DEC's first minicomputer (although the -5 pre-dated the creation of that term). Like the -8, it was a load-store architecture; its instruction set was very similar to that of the -8. A Type 154 Memory Extension Control unit was added later, to support bank switching, and thus allow the use of more than 4KW of main memory.

It was constructed out of the standard modules created for the PDP-4. It was built using the bit-slice concept, where one bit of all the registers and the data paths between them was implemented on a single PCB; a number of these boards (equal to the word length of the machine) formed the CPU. To minimize the initial basic cost, it had an I/O bus, rather than the radial links from the CPU to individual peripherals used in all earlier DEC machines, such as the 18-bit machines like the PDP-1.

External links