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DEC PDP-10 (DECSYSTEM 2020) S/N 4224

This DECSYSTEM 2020 was donated to the Rhode Island Computer Museum by the University of Massachusetts, Dartmouth (formerly Southeastern Massachusetts University).

The KS10 is the smallest model in the PDP10 family of 36 bit computers manufactured by Digital Equipment Corporation. It was introduced in 1978 as a small low cost version of the KL10. It has 512 Words of Cache Memory and supports a maximum of 512 Kwords (36-bit) of memory. ADP sold a modified version of this system that supported 1024 Kwords of memory.

This machine shipped with 512 KWords of RAM memory, a master and slave pair of TU45 Tape Drives, four RP06 Disk Drives, 32 serial ports, and a LP20 Line Printer interface.

The system had problems with the KS10 chassis power supply and the tape drives. The first problem with the tape drives was defective vacuum switches that detect the position of the tape in the vacuum columns. Replacement switches purchased from World Magnetics. The CPU cabinet and tape drives run on 115VAC 30A circuits. The RP06 disk drives are usually powered by 220VAC 30A three-phase circuits. A disk drive was modified to run on a 220VAC 30A single-phase circuit. The system now has an RM03 disk drive that came from an PDP-11/70. The RM03 is configured for 16-bit data for the PDP-11/70 and needs to be modified to work with 18 bit data for the KS10.

KS10 systems use one or more Unibus chassis for I/O.

The KS10 chassis in the 2020 contains the following boards:

Slot#Module#OptionDescription
1M8629MMA64KW RAM
2M8629MMA64KW RAM
3M8629MMA64KW RAM
4M8629MMA64KW RAM
5M8629MMA64KW RAM
6M8629MMA64KW RAM
7M8629MMA64KW RAM
8M8629MMA64KW RAM
9M8618MMCMemory Controller
10Empty
11M8623CRMMicro Controller
12M8622CRAMicro Controller
13M8620DPEData Path
14M8621DPMData Path
15Empty
16M8619UBA#3Unibus Adapter
17Empty
18M8616CSLConsole
19M8619UBA#1Unibus Adapter
20Empty
21ABM9014RH11UNIBUS to 3 H854s
21CDM7297RH11MASSBUS parity control
21EFM7296RH11MASSBUS control and status
22M7295RH11MASSBUS bus control
23M7294YARH11MASSBUS data buffer and control
24CDM5904RH11MASSBUS control transceiver
24EFM688RH11UNIBUS power fail driver
25CDM5904RH11MASSBUS control transceiver
25EFM688RH11UNIBUS power fail driver
26CDM5904RH11MASSBUS control transceiver
27CDMG727Unibus Grant
28ABM9300UNIBUS terminator
28CDMG727Unibus Grant
29ABM9300UNIBUS terminator
29CDMG727Unibus Grant

The Unibus chassis in the 2020 contains the following boards:

Slot#Module#OptionDescription
1M9014RH11UNIBUS to 3 H854s
2empty
3empty
4empty
5M7819DZ11-A8-line double-buffered async EIA with modem control
6M7819DZ11-A8-line double-buffered async EIA with modem control
7M7819DZ11-A8-line double-buffered async EIA with modem control
8M7819DZ11-A8-line double-buffered async EIA with modem control
9UM9202Unibus Jumper
9MMG727Grant
10empty
11UM9202Unibus Jumper
11MM7297RH11MASSBUS parity control
11LM7296RH11MASSBUS control and status
12M7295RH11MASSBUS bus control
13M7294YARH11MASSBUS data buffer and control
14MM5904RH11MASSBUS control transceiver
14LM6886RH11UNIBUS power fail driver
15MM5904RH11MASSBUS control transceiver
16MM5904RH11MASSBUS control transceiver
17MMG727Grant
18UM9300UNIBUS terminator
18MMG727Grant
19UM9202Unibus Jumper
20empty
21UM9202Unibus Jumper
22M8586LP20LP20 control
23M8571LP20LP20 Data Path
24UM9300UNIBUS terminator
24MM8585LP20LP20 Translation RAM


The KS10. The two TU45 two tape drives are to the right. The left TU45 contains the TM03 tape controller.
The drive to the left of the CPU is a RM03. The RP06 drive is behind the RM03.

 
This is the outside and inside of the defective LH Research power supply for the KS10 chassis.


 This is the inside of the TU45 tape drive. The large white object it the vacuum pump.

 
This is the outside and inside of the TM03 Massbus interface located in the bottom of the master TU45 tape drive.
The power supply for the Massbus interface is to the left of the TM03.

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