Description of Photograph

Published in Bird, Peter  LEO - The First Business Computer  (Wokingham: Hasler, 1994), plate 30.

This image appears in the interactive plan for our Virtual LEO I installation , p43.

Research comments: I believe that the first row of racks (those closest to the middle of the calculator room and partially seen in this photo, were responsible for interfacing LEO to the mercury delay lines (the store - LEO's memory) held under the floor.  However, this is a very early photo taken in the construction phase of LEO when racks were being moved around and added to, so it is hard to be 100% certain. As LEO became fully operational it would consist of 21 of those racks arranged in four rows. The photo shows racks from the valve side, enabling thermionic valves to be changed easily for maintenance. Accessing the racks from the other side provided the means to change electronic components in each unit.  Each rack could hold 12 units (modules) and approximately 200 valves. These valves created a lot of heat.  Each 7 foot rack was constructed to allow cool air to be drawn up from the bottom, cooling the valves with the warm air drawn up and out through a ventilation system. (CM)

Provenance
Collected by Peter Bird as part of his research for his book LEO - The First Business Computer (1994).

Date: c1950

Physical Description: 1 photographic print; black and white

Archives Hub References: CMLEO/PB/PH/1/60542
PJB/3/2/041A

Other References: DCMLEO20190510037
                  
                  
                  
                  


Comment on This Photograph

This exhibit has a reference ID of CH60542. Please quote this reference ID in any communication with the Centre for Computing History.