Difference between revisions of "System unit"
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The initial system units were [[DEC card form factor|hex]] height, four-slot assemblies. (Sometimes a number of these were wired together to form a single unit, such as in the [[PDP-11/20]]'s [[KA11]] [[Central Processing Unit|CPU]], which used three.) | The initial system units were [[DEC card form factor|hex]] height, four-slot assemblies. (Sometimes a number of these were wired together to form a single unit, such as in the [[PDP-11/20]]'s [[KA11]] [[Central Processing Unit|CPU]], which used three.) | ||
| − | + | Later on, 'double' system units (also hex-height, but nine slots wide) appeared. There were also custom backplanes (such as for the [[PDP-11/45]] and [[PDP-11/70]], in the latter backplanes for both the CPU and memories such as the [[MJ11 memory system|MJ11]] and [[MK11 memory system|MK11]]) which were even wider than that, but generally a double was the maximum width for an option. | |
Each slot held six 'connectors', DEC's term for a [[DEC edge connector contact identification|group of edge connector pins]], denominated 'A'-'F'. | Each slot held six 'connectors', DEC's term for a [[DEC edge connector contact identification|group of edge connector pins]], denominated 'A'-'F'. | ||
Revision as of 23:19, 13 January 2022
A system unit is a standard modular backplane from DEC, used mostly in UNIBUS PDP-11s.
The initial system units were hex height, four-slot assemblies. (Sometimes a number of these were wired together to form a single unit, such as in the PDP-11/20's KA11 CPU, which used three.)
Later on, 'double' system units (also hex-height, but nine slots wide) appeared. There were also custom backplanes (such as for the PDP-11/45 and PDP-11/70, in the latter backplanes for both the CPU and memories such as the MJ11 and MK11) which were even wider than that, but generally a double was the maximum width for an option.
Each slot held six 'connectors', DEC's term for a group of edge connector pins, denominated 'A'-'F'.
All the DEC chassis boxes (such as the BA11-K and BA11-L) had mechanical mountings and DC power connectors intended to hold system units.
