Difference between revisions of "PDP-8/A"

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The '''PDP-8/A''' was [[Digital Equipment Corporation|DEC]]'s last non-[[microprocessor]] [[PDP-8]]. The [[Central Processing Unit|CPU]] was a single [[DEC card form factor|hex]] board, which plugged into an [[OMNIBUS]] [[backplane]].
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{{Infobox Machine
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| name = PDP-8/A
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<!--
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| image = PDP 8 e Trondheim.jpg
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| caption = PDP-8/E front panel
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| ram = Maximum of 32 kwords in eight 4 kword banks
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-->
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| year introduced = 1976
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| form factor = [[minicomputer]]
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| word size = 12
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| physical address = 32KW (requires optional KM8-A)
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| virtual address = 4KW
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| logic type = [[Transistor-transistor logic|TTL]]
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| design type = [[clock]]ed random [[logic]]
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| clock speed = 333KHz
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| memory speed = 1.5 µseconds
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| bus arch = [[OMNIBUS]]
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| memory mgmt = bank selection, CPU mode
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| operating system = [[OS/8]], [[TSS/8]]
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| predecessor = [[PDP-8/E]]
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| successor = [[]]
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-->
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}}
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The '''PDP-8/A''' was [[Digital Equipment Corporation|DEC]]'s last non-[[microprocessor]] [[PDP-8]]. The KK8-A [[Central Processing Unit|CPU]] was a single [[DEC card form factor|hex]] board, which plugged into an [[OMNIBUS]] [[backplane]]. It supported both [[core memory|core]] [[main memory]] (MM8-AA and MM8-AB) and [[semiconductor]] (MS8-A).
  
 
There were a number of options available for use with the -8/A, including:
 
There were a number of options available for use with the -8/A, including:
  
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* KM8-A Extended Option - main memory extension and [[time-sharing]] control, etc
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* FPP8/A Floating Point Processor
 
* DKC8-AA - front panel control, real-time [[clock]], [[asynchronous serial line]] interface, etc
 
* DKC8-AA - front panel control, real-time [[clock]], [[asynchronous serial line]] interface, etc
* KM8-A Extended Option - [[main memory]] extension and [[time-sharing]] control, etc
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* FPP8/A Floating Point Processor - two hex boards, it is not part of the CPU, but uses [[Direct Memory Access|DMA]] for its instuctions and data
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The FPP8/A used two hex boards; it was not part of the CPU, but uses [[Direct Memory Access|DMA]] for its [[instruction]]s and data. Its [[floating point]] format provided three and six [[word]] formats, with 12 bits of exponent; it also supported two-word integers.
  
 
The -8/A could use either an Operator's Panel, or a Programmer's Panel (similar to the [[KY11-LB Programmer's Console|KY11-LB]]); the latter required the DKC8-AA.
 
The -8/A could use either an Operator's Panel, or a Programmer's Panel (similar to the [[KY11-LB Programmer's Console|KY11-LB]]); the latter required the DKC8-AA.

Revision as of 17:04, 3 September 2018


PDP-8/A
Year Introduced: 1976
Form Factor: minicomputer
Word Size: 12
Logic Type: TTL
Clock Speed: 333KHz
Memory Speed: 1.5 µseconds
Physical Address Size: 32KW (requires optional KM8-A)
Virtual Address Size: 4KW
Memory Management: bank selection, CPU mode
Bus Architecture: OMNIBUS
Operating System: OS/8, TSS/8
Predecessor(s): PDP-8/E


The PDP-8/A was DEC's last non-microprocessor PDP-8. The KK8-A CPU was a single hex board, which plugged into an OMNIBUS backplane. It supported both core main memory (MM8-AA and MM8-AB) and semiconductor (MS8-A).

There were a number of options available for use with the -8/A, including:

The FPP8/A used two hex boards; it was not part of the CPU, but uses DMA for its instructions and data. Its floating point format provided three and six word formats, with 12 bits of exponent; it also supported two-word integers.

The -8/A could use either an Operator's Panel, or a Programmer's Panel (similar to the KY11-LB); the latter required the DKC8-AA.

The -8/A came either as a kit of boards, or as a complete system including a chassis, power supply and backplane; in the latter form, there was a list of different configurations.