The IBM 308X is a line of mainframe computers, of which the first model, the Model 3081 Processor Complex, was introduced November 12, 1980.[1][NB 1] It consisted of a 3081 Processor Unit with supporting units.
Later models in the series were the 3083[2] and the 3084.[3] The 3083 was announced March 31 and the 3084 on September 3, both in 1982.
The IBM 308X line introduced the System/370 Extended Architecture[4] (S/370-XA) required by the new MVS/SP V2[5] and the Start Interpretive Execution[6] (SIE) instruction used by the new Virtual Machine/eXtended Architecture Migration Aid[7] (VM/XA MA).
All three 308X systems, which IBM had marketed as "System/370-Compatibles,"[8] were withdrawn August 4, 1987.