Difference between revisions of "System unit"
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| − | A '''system unit''' is a standard modular [[backplane]] from [[DEC]], used mostly in [[UNIBUS]] [[PDP-11]]s. | + | A '''system unit''' is a standard modular [[backplane]] from [[Digital Equipment Corporation|DEC]], used mostly in [[UNIBUS]] [[PDP-11]]s. |
| − | 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]] [[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.) |
| − | Late 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]], the latter 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. | + | Late 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. |
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. | 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. | ||
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Revision as of 12:57, 29 October 2017
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.)
Late 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.
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.
