scram switch = S = scratch monkey

scratch

1. [from `scratchpad'] adj. Describes a data structure or recording medium attached to a machine for testing or temporary-use purposes; one that can be scribbled on without loss. Usually in the combining forms `scratch memory', `scratch register', `scratch disk', `scratch tape', `scratch volume'. See also scratch monkey. 2. [primarily IBM] vt. To delete (as in a file).

scram switch = S = scratch monkey