What is svc in mainframe?

A Supervisor Call instruction (SVC) is a hardware instruction in the System/360 family of IBM mainframe computers up to contemporary zSeries (as well as non-IBM mainframe computers such as the Amdahl 470V/5, 470V/6, 470V/7, 470V/8, 580, 5880, 5990M, and 5990A, and others; Univac 90/60, 90/70 and 90/80, and possibly. In computers, especially IBM mainframes, a supervisor call (SVC) is a processor instruction that directs the processor to pass control of the computer to the operating system's supervisor program. The SVC is a special machine instruction (hex 0A) that programs use to communicate with the operating system. SVC 4 (0A04) · SVC 5 (0A05) · SVC 6 (0A06) · SVC 7 (0A07) · SVC 8 (0A08) · SVC 9 (0A09) · SVC 10 (0A0A) · SVC 11 (0A0B) · SVC 12 (0A0C) · SVC 13 ( 0A0D). The SCVTSVCT field in the SCVT points to the SVC table. To supply user-written SVC routines to the system, you place descriptions of your user SVC routines in SYS1.