Card from a Card-Capacitor Read-Only Store (CCROS), System/360 Model 30

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  • Details
  • Description
Date Introduced
1965 ca.
Photographer
Richards, Mark
Dimensions
overall: 1/8 in x 7 1/4 in x 3 1/4 in
Manufacturer
International Business Machines Corporation (IBM)
Credit Line
Gift of Brian Knittel
Copyright Owner
© Mark Richards
Location
United States
Keywords
microcode; microprogramming; Storage; Memory
Object ID
102630209

The CCROS held microcode in Model 30s. Microcode could be easily changed by swapping one punched card for another with a different hole pattern. That allowed a Model 30 to emulate differently configured IBM 1401 computers — important for customers considering upgrading from a 1401.