Difference between revisions of "PDP-8/L"

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* The -8/L used a positive I/0 bus, not negative
 
* The -8/L used a positive I/0 bus, not negative
 
* The -8/L was not pre-wired for a number of devices
 
* The -8/L was not pre-wired for a number of devices
* The -8/L could not accomodate the Extended Arithmetic Element
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* The -8/L could not accomodate the [[Extended Arithmetic Element]]
 
* The -8/L supported a maximum of 8KW of [[main memory]]
 
* The -8/L supported a maximum of 8KW of [[main memory]]
  
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* DW08-A Negative I/O Bus Interface, to allow use of older PDP-8 devices
 
* DW08-A Negative I/O Bus Interface, to allow use of older PDP-8 devices
* MC-8/L Memory Extension Control, which was needed to support more than 4K [[word]]s of memory
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* MC-8/L Memory Extension Control, [[bank switching]] needed to support more than 4K [[word]]s of memory
* MP-8/L Memory Parity
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* MP-8/L Memory [[Parity]]
  
 
It could perform an addition to the [[accumulator]] in 3.2 µseconds, and a subtraction in 6.4 µseconds.
 
It could perform an addition to the [[accumulator]] in 3.2 µseconds, and a subtraction in 6.4 µseconds.
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==External links==
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* [http://www.bitsavers.org/pdf/dec/pdp8l PDP-8/L] - Original PDP-8/L documents
  
 
{{Nav PDP-8}}
 
{{Nav PDP-8}}
  
 
[[Category: PDP-8s]]
 
[[Category: PDP-8s]]

Revision as of 03:01, 16 May 2021


PDP-8/L
PDP-8'L Astrotype.jpg
PDP-8/L from an ICS Astrotype system
Year Introduced: 1968
Form Factor: minicomputer
Word Size: 12
Logic Type: TTL
Design Type: clocked random logic
Clock Speed: 312KHz
Memory Speed: 1.6 µseconds
Physical Address Size: 8KW (requires optional MC-8/L)
Virtual Address Size: 4KW
Memory Management: none
Bus Architecture: positive logic I/O bus
Operating System: TSS/8
Predecessor(s): PDP-8/I
Successor(s): PDP-8/E


The PDP-8/L was a effectively a cost-reduced version of the PDP-8/I in the PDP-8 line; it apparently had the same CPU as the -8/I.

The primary differences between the two are:

  • The -8/L was slightly slower
  • The -8/L used a positive I/0 bus, not negative
  • The -8/L was not pre-wired for a number of devices
  • The -8/L could not accomodate the Extended Arithmetic Element
  • The -8/L supported a maximum of 8KW of main memory

Options for the -8/L included:

  • DW08-A Negative I/O Bus Interface, to allow use of older PDP-8 devices
  • MC-8/L Memory Extension Control, bank switching needed to support more than 4K words of memory
  • MP-8/L Memory Parity

It could perform an addition to the accumulator in 3.2 µseconds, and a subtraction in 6.4 µseconds.

External links

  • PDP-8/L - Original PDP-8/L documents