High Quality Content by WIKIPEDIA articles! In IBM mainframe computers such as S/360, and all its successors up to contemporary zSeries, a supervisor call instruction (SVC) is a processor's instruction requesting a function from a supervisor (usually a kernel). IBM mainframes operate in either of two states: problem state and supervisor state. Problem state does not relate to difficulties, but to the state in which the computer is supposed to solve the user's problem, such as administration or text processing. In supervisor state, programs have privileges to perform management tasks.