System for repositioning an I/O device to a predetermined position to retry a program without knowledge of which part of the program caused the retry

摘要

Repositioning within an input/output device is accomplished without any knowledge of where the input/output device is currently positioned. The input/output device is repositioned to a predetermined position, in order for a program to be retried. The predetermined position is determined from a previously executed program. The previously executed program is scanned looking for commands. For each command found, a position identifier is adjusted based upon the type of command. When the scan and adjustments are complete, the position identifier represents the predetermined position used for repositioning the input/output device.