Dublin Core
Title
Digital PDP-9 Backplane Assembly
Description
A photo of a Digital Equipment Corporation wire-wrapped backplane assembly for the PDP-9 computer.
This photograph demonstrates the design philosophy of DEC computer design in the late 1960s and early 1970s: a wire-wrapped (no solder) insulated backplane that was backed with a card cage which was filled with standardized logic module cards that plugged into the backplane. Groups of these cards were used to create the CPU and other parts of the computer as signals flowed from one card to the next. The card ID numbers are visible. For example, cards with the "B" prefix noted logic (like flip-flops or gates), "R" for register or drivers, with G,W,M denoting other specialized modules.
This design pre-dates the widespread use of integrated circuits (chips). The logic modules were composed of individual transistors, resistors, capacitors, diodes, etc.
The use of standardized cards made construction and maintenance of the computer much more economical.
Visible logic modules:
B117 - Positive NOR gate
R107 - Inverter
R113 - NAND/NOR gate
R123 - Input BUS gate
R202 - Dual Flip-Flop
R601 - Pulse Amplifier
R602 - Pluse Amplifiers
W005- Clamp Loads,
W103 - Device Selector
W512 - Positive Level Converters
This photograph demonstrates the design philosophy of DEC computer design in the late 1960s and early 1970s: a wire-wrapped (no solder) insulated backplane that was backed with a card cage which was filled with standardized logic module cards that plugged into the backplane. Groups of these cards were used to create the CPU and other parts of the computer as signals flowed from one card to the next. The card ID numbers are visible. For example, cards with the "B" prefix noted logic (like flip-flops or gates), "R" for register or drivers, with G,W,M denoting other specialized modules.
This design pre-dates the widespread use of integrated circuits (chips). The logic modules were composed of individual transistors, resistors, capacitors, diodes, etc.
The use of standardized cards made construction and maintenance of the computer much more economical.
Visible logic modules:
B117 - Positive NOR gate
R107 - Inverter
R113 - NAND/NOR gate
R123 - Input BUS gate
R202 - Dual Flip-Flop
R601 - Pulse Amplifier
R602 - Pluse Amplifiers
W005- Clamp Loads,
W103 - Device Selector
W512 - Positive Level Converters
Creator
Digital Equipment Corporation
Date
ca 1967
Contributor
Charles Valentine
Identifier
2026.67