IBM Transformer Read-Only Store (TROS)
IBM Transformer Read-Only Store
In moving away from vacuum tubes, IBM engineers experimented with read-only stores as a way to reduce the number of expensive transistors needed for control logic. First used in SCAMP, a small computer developed at the IBM Hursley Laboratory for scientific applications, TROS was used in the System/360 Model 40 to facilitate emulation of the older 1401 and 1410 computers in addition to the basic Model 40 control functions.