Difference between revisions of "PDP-9"

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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.
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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.
  
 
Its principal intended use was for [[real-time system]]s, 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.
 
Its principal intended use was for [[real-time system]]s, 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.
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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.
 
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==Further reading==
 
==Further reading==
  
 
''(All available online through [[BitSavers]].)''
 
''(All available online through [[BitSavers]].)''
 
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* [http://www.bitsavers.org/pdf/dec/pdp9/PDP-9_UsersManual.pdf PDP-9 User Handbook]
 
 
 
 
==External links==
 
==External links==
  
 
* [http://www.bitsavers.org/pdf/dec/pdp9/ PDP-9] - Has manuals for KE09, KG09, KX09, KF09, etc
 
* [http://www.bitsavers.org/pdf/dec/pdp9/ PDP-9] - Has manuals for KE09, KG09, KX09, KF09, etc
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** [http://www.bitsavers.org/pdf/dec/pdp9/PDP-9_UsersManual.pdf PDP-9 User Handbook]
 
** [http://www.bitsavers.org/pdf/dec/pdp9/DEC-09-I3CA-D-68.pdf TC02 DECtape Transport Control Instruction Manual]
 
** [http://www.bitsavers.org/pdf/dec/pdp9/DEC-09-I3CA-D-68.pdf TC02 DECtape Transport Control Instruction Manual]
 
** [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]
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[[Category:DEC Systems]]
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[[Category: DEC Systems]]

Revision as of 23:31, 11 February 2022


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)


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.

Instructions had a 4-bit opcode, 1 bit of indirect, and 13 bits of address. It was a load-store architecture, with a single accumulator. 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.

Multiply/divide was a hardware option, the KE09A Extended Arithmetic Element, 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.

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.

External links