IBM Phases Out Vacuum Tubes

Vacuum tube module from early 700 series[1] IBM computer
Vacuum tube module from early 700 series IBM computer.

Having begun shipping the IBM 608 calculator, the first fully transistorized computer, in 1957 IBM phased out vacuum tubes in computer design:

“It shall be the policy of IBM to use solid-state circuitry in all machine developments. Furthermore, no new commercial machines or devices shall be announced which make primary use of tube circuitry.”

By this time IBM was satisfied with the reliability of transistors and convinced of the advantages of solid state over vacuum tube technology.  

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