DECSYSTEM-2020 KS10, S/N 4224
This DECSYSTEM 2020 was originally installed at 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 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. The disk drive was modified to run on a 220VAC 30A single-phase circuit. I also have an RM03 disk drive from an 11/70. I need to modify this drive to work with 18 bit data.
KS10 systems use one or more Unibus chassis for I/O.
The KS10 chassis in the 2020 contains the following boards:
Slot#
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21AB
21CD
21EF
22
23
24CD
24EF
25CD
25EF
26CD
27CD
28AB
28CD
29AB
29CD
Module#
M8629
M8629
M8629
M8629
M8629
M8629
M8629
M8629
M8618
M8623
M8622
M8620
M8621
M8619
M8616
M8619
M9014
M7297
M7296
M7295
M7294YA
M5904
M688
M5904
M688
M5904
MG727
M9300
MG727
M9300
MG727
Option
MMA
MMA
MMA
MMA
MMA
MMA
MMA
MMA
MMC
CRM
CRA
DPE
DPM
UBA#3
CSL
UBA#1
RH11
RH11
RH11
RH11
RH11
RH11
RH11
RH11
RH11
RH11
Description
64KW RAM
64KW RAM
64KW RAM
64KW RAM
64KW RAM
64KW RAM
64KW RAM
64KW RAM
Memory Controller
Empty
Micro Controller
Micro Controller
Data Path
Data Path
Empty
Unibus Adapter
Empty
Console
Unibus Adapter
Empty
UNIBUS to 3 H854s
MASSBUS parity control
MASSBUS control and status
MASSBUS bus control
MASSBUS data buffer and control
MASSBUS control transceiver
UNIBUS power fail driver
MASSBUS control transceiver
UNIBUS power fail driver
MASSBUS control transceiver
Unibus Grant
UNIBUS terminator
Unibus Grant
UNIBUS terminator
Unibus Grant
The Unibus chassis in the 2020 contains the following boards:
Slot#
1
2
3
4
5
6
7
8
9U
9M
10
11U
11M
11L
12
13
14M
14L
15M
16M
17M
18U
18M
19U
20
21U
22
23
24U
24M
Module#
M9014
empty
empty
empty
M7819
M7819
M7819
M7819
M9202
MG727
empty
M9202
M7297
M7296
M7295
M7294YA
M5904
M6886
M5904
M5904
MG727
M9300
MG727
M9202
empty
M9202
M8586
M8571
M9300
M8585
Option
RH11
DZ11-A
DZ11-A
DZ11-A
DZ11-A
RH11
RH11
RH11
RH11
RH11
RH11
RH11
RH11
LP20
LP20
LP20
Description
UNIBUS to 3 H854s
8-line double-buffered async EIA with modem control
8-line double-buffered async EIA with modem control
8-line double-buffered async EIA with modem control
8-line double-buffered async EIA with modem control
Unibus Jumper
Grant
Unibus Jumper
MASSBUS parity control
MASSBUS control and status
MASSBUS bus control
MASSBUS data buffer and control
MASSBUS control transceiver
UNIBUS power fail driver
MASSBUS control transceiver
MASSBUS control transceiver
Grant
UNIBUS terminator
Grant
Unibus Jumper
Unibus Jumper
LP20 control
LP20 Data Path
UNIBUS terminator
LP20 Translation RAM
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.