Difference between revisions of "PDP-9"

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(Front panel functions used microcode. (Just some, or all?))
(List front panel functions implemented with microcode; Memory Extension was bank switching)
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| price = US$30K (8KW system)
 
| price = US$30K (8KW system)
 
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[[Image:CIPG-PDP9.png|200px|thumb|right|PDP-9 at MIT Cognitive Information Processing Group.]]
  
 
The '''PDP-9''' was [[Digital Equipment Corporation|DEC]]'s fourth 18-bit computer, and the first DEC [[Central Processing Unit|CPU]] to use [[microcode]]. A little over 400 were built. It was a re-implementation of the [[PDP-7]]; the PDP-9 'Basic Software System' manual indicates that most PDP-7 software will run, un-modified.
 
The '''PDP-9''' was [[Digital Equipment Corporation|DEC]]'s fourth 18-bit computer, and the first DEC [[Central Processing Unit|CPU]] to use [[microcode]]. A little over 400 were built. It was a re-implementation of the [[PDP-7]]; the PDP-9 'Basic Software System' manual indicates that most PDP-7 software will run, un-modified.
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It was a [[load-store architecture]], with a single [[accumulator]]. [[Instruction]]s had a 4-bit opcode, 1 bit of indirect, and 13 bits of address. Opcodes 000-060 were memory-reference instructions; for non-memory operations ('074' opcode), and [[input/output|I/O]] ('070'), bits in the 'address' field were used to specify details. '064' opcodes were for the optional [[Extended Arithmetic Element|EAE]].
 
It was a [[load-store architecture]], with a single [[accumulator]]. [[Instruction]]s had a 4-bit opcode, 1 bit of indirect, and 13 bits of address. Opcodes 000-060 were memory-reference instructions; for non-memory operations ('074' opcode), and [[input/output|I/O]] ('070'), bits in the 'address' field were used to specify details. '064' opcodes were for the optional [[Extended Arithmetic Element|EAE]].
  
For the high-speed [[read-only memory|ROM]] needed for a microcoded design, it used hard-wired [[core memory]], similar to that in the [[Apollo Guidance Computer]]. [[Microinstruction]]s were 36 bits wide, of which 6 were the 'control memory address', the [[address]] of the next one; there was no micro-[[Program Counter|PC]]. Conditional micro-branching was available by modifying the CMA during that microinstruction. [[Front panel]] functions used microcode.
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For the high-speed [[read-only memory|ROM]] needed for a microcoded design, it used hard-wired [[core memory]], similar to that in the [[Apollo Guidance Computer]]. [[Microinstruction]]s were 36 bits wide, of which 6 were the 'control memory address', the [[address]] of the next one; there was no micro-[[Program Counter|PC]]. Conditional micro-branching was available by modifying the CMA during that microinstruction. Some [[front panel]] functions (START, EXAMINE/DEPOSIT (NEXT), and READ IN) are implemented with microcode.
  
Multiply/divide was a hardware option, the KE09A EAE, which also performed shifting (it was installed in pre-wired slots in the CPU's [[backplane]]). Use of more than 8KW of main memory (all core in the PDP-9) required the Memory Extension Control, KG09A. A [[memory management]] option, the KX09A, which included a boundary [[register]] to set the boundary between protected and un-protected memory, and two modes for the CPU, was also available.
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Multiply/divide was a hardware option, the KE09A EAE, which also performed shifting; it was installed in pre-wired slots in the CPU's [[backplane]]. Use of more than 8KW of main memory (all core in the PDP-9) required the Memory Extension Control, KG09A, which provided [[bank switching]]. A [[memory management]] option, the KX09A, was also available; it included a [[register]] to set the boundary between protected and un-protected memory, and two modes for the CPU.
  
 
The KF09A Automatic Priority Interrupt option provided 8 levels of [[interrupt]] priority, each of which could support up to 8 [[peripheral|devices]]. Each device could provide its own [[interrupt vector]]. The DM09 [[Direct Memory Access]] Channel Multiplexor Adapter provided high-speed devices with direct access to main memory for data transfers.
 
The KF09A Automatic Priority Interrupt option provided 8 levels of [[interrupt]] priority, each of which could support up to 8 [[peripheral|devices]]. Each device could provide its own [[interrupt vector]]. The DM09 [[Direct Memory Access]] Channel Multiplexor Adapter provided high-speed devices with direct access to main memory for data transfers.
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A large range of [[peripheral]]s were available, including [[DECtape]] (via the TC02 controller), [[magnetic tape]] (via the TC59), [[drum]] (RM09 controller) and [[fixed-head disk]] (RB09; and RS09, via the RF09 controller). The RM09 and RB09 use the DM09.
 
A large range of [[peripheral]]s were available, including [[DECtape]] (via the TC02 controller), [[magnetic tape]] (via the TC59), [[drum]] (RM09 controller) and [[fixed-head disk]] (RB09; and RS09, via the RF09 controller). The RM09 and RB09 use the DM09.
  
[[Image:CIPG-PDP9.png|200px|thumb|right|PDP-9 at MIT Cognitive Information Processing Group.]]
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{{semi-stub}}
  
 
==See also==
 
==See also==
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** [http://www.bitsavers.org/pdf/dec/pdp9/DEC-09-I3CA-D-69.pdf TC02 DECtape Control Maintenance Manual]
 
** [http://www.bitsavers.org/pdf/dec/pdp9/DEC-09-I3CA-D-69.pdf TC02 DECtape Control Maintenance Manual]
 
* [https://bitsavers.org/pdf/dartmouth/theses/Blean_-_The_PDP-9_Mini_Time-Sharing_System_197206.pdf Dartmouth PDP-9 Mini Time-Sharing System]
 
* [https://bitsavers.org/pdf/dartmouth/theses/Blean_-_The_PDP-9_Mini_Time-Sharing_System_197206.pdf Dartmouth PDP-9 Mini Time-Sharing System]
 
{{semi-stub}}
 
  
 
{{Nav DEC}}
 
{{Nav DEC}}

Revision as of 11:39, 24 July 2023


PDP-9
Manufacturer: Digital Equipment Corporation
Year First Shipped: 1966
Form Factor: minicomputer
Word Size: 18 bits
Logic Type: PNP Transistor FLIP CHIPs
Design Type: microcoded
Memory Speed: 1 μsec
Physical Address Size: 15 bits (32K words)
Virtual Address Size: 13 bits (direct), 15 bits (extended)
Memory Management: bounds register
Predecessor(s): PDP-7
Successor(s): PDP-15
Price: US$30K (8KW system)


PDP-9 at MIT Cognitive Information Processing Group.

The PDP-9 was DEC's fourth 18-bit computer, and the first DEC CPU to use microcode. A little over 400 were built. It was a re-implementation of the PDP-7; the PDP-9 'Basic Software System' manual indicates that most PDP-7 software will run, un-modified.

Its principal intended use was for real-time systems, including data recording and process control. A variety of models were offered; the basic system provided 8K words of main memory, and the PDP-9/L was a cost-reduced system with cheaper peripherals and 4KW of memory.

It was a load-store architecture, with a single accumulator. Instructions had a 4-bit opcode, 1 bit of indirect, and 13 bits of address. Opcodes 000-060 were memory-reference instructions; for non-memory operations ('074' opcode), and I/O ('070'), bits in the 'address' field were used to specify details. '064' opcodes were for the optional EAE.

For the high-speed ROM needed for a microcoded design, it used hard-wired core memory, similar to that in the Apollo Guidance Computer. Microinstructions were 36 bits wide, of which 6 were the 'control memory address', the address of the next one; there was no micro-PC. Conditional micro-branching was available by modifying the CMA during that microinstruction. Some front panel functions (START, EXAMINE/DEPOSIT (NEXT), and READ IN) are implemented with microcode.

Multiply/divide was a hardware option, the KE09A EAE, which also performed shifting; it was installed in pre-wired slots in the CPU's backplane. Use of more than 8KW of main memory (all core in the PDP-9) required the Memory Extension Control, KG09A, which provided bank switching. A memory management option, the KX09A, was also available; it included a register to set the boundary between protected and un-protected memory, and two modes for the CPU.

The KF09A Automatic Priority Interrupt option provided 8 levels of interrupt priority, each of which could support up to 8 devices. Each device could provide its own interrupt vector. The DM09 Direct Memory Access Channel Multiplexor Adapter provided high-speed devices with direct access to main memory for data transfers.

A large range of peripherals were available, including DECtape (via the TC02 controller), magnetic tape (via the TC59), drum (RM09 controller) and fixed-head disk (RB09; and RS09, via the RF09 controller). The RM09 and RB09 use the DM09.

See also

External links