DCJ11 Processors

The DCJ11-based processor is a microcomputer with a 22-bit address bus, a 16-bit data bus, full floating point instruction set and a built-in memory management unit (MMU). It can address up to 4 MB of memory and reserves the top 8 KB of the address space for I/O devices. The processor has kernel, supervisor and user modes and provides separate instruction and data spaces for each, which in turn, provides more addressable space to individual programs.

This processor was used in the PDP-11/53, PDP-11/73, PDP-11/83 and PDP-11/93 line of Q-bus computers. It was also used in the PDP-11/84 and PDP-11/94 line of UNIBUS computers.

The table below contains a breakdown and comparison of the DCJ11-based processors.

DCJ11 Processors and Their Capabilities
Processor LSI-11/53 LSI-11/53+ LSI-11/731 LSI-11/732 LSI-11/83 LSI-11/93
Module Number M7554 M7554-01 M7554-02 M7554-04 M8192 M8192-YB M8192-YC M8190 M8190-AB M8190-AC M8190-AD M8190-AE M8981-AA M8981-BA
Model Number KDJ11-DA KDJ11-DA KDJ11-DB KDJ11-DD KDJ11-AA KDJ11-AB KDJ11-AC KDJ11-BC KDJ11-BB KDJ11-BD KDJ11-BA KDJ11-BF KDJ11-EA KDJ11-EB
Introduced 1986 1987 1987 1988 1984 1985 1985 1986 1986 1986 1987 1987 1990 1990
Discontinued 1988 1988 1988 1988 1996 1996 1996
Module Size Quad Quad Quad Quad Dual Dual Dual Quad Quad Quad Quad Quad Quad Quad
Chipset J11 J11 J11 J11 J11 J11 J11 J11 J11 J11 J11 J11 J11 J11
FPJ11 Compatible no no no no no3 yes onboard no yes onboard yes onboard onboard onboard
PMI Support no no no no no no no yes yes yes yes yes yes yes
Cache no no no no Single Tag Single Tag Single Tag Dual Tag Dual Tag Dual Tag Dual Tag Dual Tag no4 no4
Memory Management yes yes yes yes yes yes yes yes yes yes yes yes yes yes
Performance (VUP) 0.29 0.29 0.29 0.45 0.45 0.45 0.45 0.45 0.45 0.72 0.72 1.00 1.00
Dhrystones/sec 690/7496 690/7496 690/7496 763/8106 763/8106 763/8106 810/8626
931/9987
810/8626
931/9987
810/8626
931/9987
930/9886
1100/11817
930/9886
1100/11817
Whetstones (KIPS) 91.7 91.7 91.7 93.5 93.5 200.0 97.18
101.09
97.18
101.09
217.48
243.99
113.68
120.59
250.08
285.79
Clock Frequency 15 MHz 15 MHz 15 MHz 18 MHz 15 MHz 15 MHz 15 MHz 15 MHz 15 MHz 15 MHz 18 MHz 18 MHz 18 MHz 18 MHz
Q-bus Address Size 22-bits 22-bits 22-bits 22-bits 22-bits 22-bits 22-bits 22-bits 22-bits 22-bits 22-bits 22-bits 22-bits 22-bits
Q-bus Interrupts 4-level 4-level 4-level 4-level 4-level 4-level 4-level 4-level 4-level 4-level 4-level 4-level 4-level 4-level
RAM Capacity 4 MB 4 MB 4 MB 4 MB 4 MB 4 MB 4 MB 4 MB 4 MB 4 MB 4 MB 4 MB 4 MB 4 MB
Onboard RAM 0.5 MB 0.5 MB 1.5 MB 1.5 MB no no no no no no no no 2 MB 4 MB
Onboard ROM 32 KB 32 KB 32 KB 32 KB no no no 16 KB5 16 KB5 16 KB5 16 KB5 16 KB5 yes yes
Onboard LTC Register yes yes yes yes yes yes yes yes yes yes yes yes yes yes
Onboard Serial Ports 2 2 2 2 no no no 1 1 1 1 1 7 7
ODT Microcode yes yes yes yes yes yes yes yes yes yes yes yes yes yes
Boot Firmware yes yes yes yes no no no yes yes yes yes yes yes yes
Self-Test Diagostics yes yes yes yes no no no yes yes yes yes yes yes yes
Memory Refresh yes yes yes yes no no no yes yes yes yes yes yes yes
Termination 120 ohms 120 ohms 120 ohms 120 ohms 250 ohms 250 ohms 250 ohms 120 ohms 120 ohms 120 ohms 120 ohms 120 ohms 120 ohms 120 ohms
AC Bus Load 3 3 3 3 3.4 3.4 3.4 1 1 1 1 1 1 1
DC Bus Load 1 1 1 1 1 1 1 1 1 1 1 1 1 1
+5V Load 2.5 A 2.9 A 2.9 A 2.9 A 4.5 A 4.5 A 4.5 A 5.5 A 5.5 A 5.5 A 5.5 A 5.5 A 4.5 A 4.5 A
+12V Load 0.18 A 0.17 A 0.17 A 0.17 A 0.1 A 0.1 A 0.1 A 0.1 A 0.1 A 0.6 A 0.6 A

1 Sometimes referred to as an LSI-11/73A processor.
2 Sometimes referred to as an LSI-11/73B, or LSI-11/73+ processor.
3 The KDJ11-AA is incompatible with the FPJ11-AA, but can be upgraded to be FPJ11-AA compatible. See uNOTE # 025.
4 Due to the speed of the onboard memory, the cache is no longer needed.
5 Supports 2K & 8K ROMs.
6 With Q-bus memory. The first number is without register declarations, the second is with register declarations.
7 With PMI memory. The first number is without register declarations, the second is with register declarations.
8 Average performance measured using the C version of Whetstone v2.1, using Q-bus memory.
9 Average performance measured using the C version of Whetstone v2.1, using PMI memory.

Summary

Any of the LSI-11/73 processors would be desirable to own. They are farily common and affordable. One thing to watch out for is the KDJ11-AA module, which has no FPJ11 support. The easiest way to tell is by looking at the module number on the ejector handles. The photo below is of an M8192-YB, which has FPJ11 support. If the right-hand ejector handle, circled in red, were blank, then it would likely be a KDJ11-AA processor. The FPJ11 socket is circled in blue.

M8192 Processor

The M8192 and M8190 are both LSI-11/73 processors and are generally differentiated by referring to them as LSI-11/73A and LSI-11/73B, respectively. The LSI-11/73A processor is a stripped down unit, with just a CPU and cache, whereas the LSI-11/73B processor is a nearly identical, but slower version of the LSI-11/83 processor.

The LSI-11/83 & 93 processors are more difficult to find, and much more expensive. LSI-11/53 processors are somewhat common and cost about the same as an LSI-11/73B, even though they are around 15% slower, due to the lack of a cache. They do contain quite a bit of memory, however, which helps to even out the value.

References

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