The ??UR (Unit Reserved) command reserves a unit to allow maintenance to be performed or makes a previously reserved unit available for normal use. Once a unit has been reserved, it is no longer available for assignment to user programs.

Syntax

Explanation

This command is the same as the nonprimitive UR (Unit Reserved) command, except that it is executed by a stack independent of the CONTROLLER stack.

You can use this command even when the CONTROLLER stack is suspended.