AccessionIndex: TCD-SCSS-T.20121208.013 Accession Date ......2012/12/08 · Figure 5: Plessey...
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AccessionIndex: TCD-SCSS-T.20121208.013 Accession Date: 8-Dec-2012 Accession By: Dr.Jeremy Jones Object name: Plessey Core Store Vintage: c.196x Synopsis: Plessey 66/942 low-density early stacked core memory array. S/N: 11788. Description: This is a low-density early stacked 1k x 24-bit core memory array, made by Plessey Components Ltd, Towcester, England. Plessey made core memories for a number of computer companies, and for example made 48-bit core memories for the Ferranti Atlas and for the English Electric KDF9, and the Atlas Supervisor Memory stored 1k words, so it is possible that it is a 24-bit slice of part of the core memory of one of these machines. However the robust construction of the unit and its colour suggests a military application, and given its weight more likely for the army or navy. The core memory is in a grey housing, ??? x ??? x ?? mm (approx. 225 x 125 x 100 mm). On the top are two manufacturing labels. The sloping ends have two DB-37M male connectors, labelled YDRIVE, SENSE, XDRIVE and INHIBIT. Internally there is a base board, a top board, 13 memory layers, and the wiring looms which connect the memory layers to the D-type connectors. The middle 32 pins on two sides of the lowest memory layer are soldered to the base board and similarly with the top memory layer and top board. The other memory layers are sparsely wired on the other two sides. The underside of the base board has a matrix of low-power signal diodes (very like 1N914). All the components are passive, there don’t appear to be any active components. The additional paper label states that this is a stack of 24 planes, each a 32 x 32 array in the X and Y dimensions, representing a 1Kword RAM. Presumably there are two planes per layer, and the implication is that there is an additional redundancy layer. Atlas (but not KDF9) core memories included extra (redundant) parity bits. Accession Index Object with Identification TCD-SCSS-T.20121208.013 Plessey 66/942 Core Store Type No: 66/942. Made by Plessey Components, Towcester, England. S/N: 11788 Ref No: [blank] Marking: ‘A stack of 24 planes 1Kword RAM 32 x by 32 y’ This unit was given to Dr.Jeremy Jones by his father, who had worked in the U.K. computer industry. References: 1. Magnetic-core Memory, see: http://en.wikipedia.org/ Visited 8-Jul-2015.
Transcript of AccessionIndex: TCD-SCSS-T.20121208.013 Accession Date ......2012/12/08 · Figure 5: Plessey...
AccessionIndex: TCD-SCSS-T.20121208.013 Accession Date: 8-Dec-2012 Accession By: Dr.Jeremy Jones Object name: Plessey Core Store Vintage: c.196x Synopsis: Plessey 66/942 low-density early stacked core memory array. S/N: 11788. Description: This is a low-density early stacked 1k x 24-bit core memory array, made by Plessey Components Ltd, Towcester, England. Plessey made core memories for a number of computer companies, and for example made 48-bit core memories for the Ferranti Atlas and for the English Electric KDF9, and the Atlas Supervisor Memory stored 1k words, so it is possible that it is a 24-bit slice of part of the core memory of one of these machines. However the robust construction of the unit and its colour suggests a military application, and given its weight more likely for the army or navy. The core memory is in a grey housing, ??? x ??? x ?? mm (approx. 225 x 125 x 100 mm). On the top are two manufacturing labels. The sloping ends have two DB-37M male connectors, labelled YDRIVE, SENSE, XDRIVE and INHIBIT. Internally there is a base board, a top board, 13 memory layers, and the wiring looms which connect the memory layers to the D-type connectors. The middle 32 pins on two sides of the lowest memory layer are soldered to the base board and similarly with the top memory layer and top board. The other memory layers are sparsely wired on the other two sides. The underside of the base board has a matrix of low-power signal diodes (very like 1N914). All the components are passive, there don’t appear to be any active components. The additional paper label states that this is a stack of 24 planes, each a 32 x 32 array in the X and Y dimensions, representing a 1Kword RAM. Presumably there are two planes per layer, and the implication is that there is an additional redundancy layer. Atlas (but not KDF9) core memories included extra (redundant) parity bits.
Accession Index Object with Identification TCD-SCSS-T.20121208.013
Plessey 66/942 Core Store Type No: 66/942. Made by Plessey Components, Towcester, England. S/N: 11788 Ref No: [blank] Marking: ‘A stack of 24 planes 1Kword RAM 32 x by 32 y’
This unit was given to Dr.Jeremy Jones by his father, who had worked in the U.K. computer industry. References: 1. Magnetic-core Memory, see:
http://en.wikipedia.org/ Visited 8-Jul-2015.
Figure 1: Plessey 66/942 Core Store three-quarter view
Figure 2: Plessey 66/942 Core Store, enhanced closeup of paper label
‘A STACK OF 24 PLANES
1KWORD RAM 32 x by 32 y’
Figure 3: Plessey 66/942 Core Store top view
Figure 4: Plessey 66/942 Core Store Y-drive connector closeup
Figure 5: Plessey 66/942 Core Store X-drive connector closeup
Figure 6: Plessey 66/942 Core Store right side view
Note the damage to the top layer
Figure 7: Plessey 66/942 Core Store bottom view
Figure 8: Plessey 66/942 Core Store left side closeup
Figure 9: Plessey 66/942 Core Store left side closeup from other end
