Method and apparatus to determine when all outstanding fetches are complete

An apparatus for determining completion of all of one or more operations for a particular input/output device initiated prior to an inquiry start time, the apparatus comprising:

• an input/output operator;
• one or more operation requesters;
• one or more in-progress bits, each in-progress bit corresponding to a respective associated one of said one or more operations for said input/output devices, each of said one or more in-progress bits being set when said associated one of said one or more operations is initiated, and being cleared when said associated one or more operations is completed;
• and
• one or more snapshot bits of equal number to said in-progress bits.

A computer readable medium on which is embedded a program, the program comprising components that execute a method for determining completion of all of one or more operations for a particular input/output device initiated prior to an inquiry start time, the method comprising:

• providing one or more in-progress bits, each in-progress bit corresponding to a respective associated one of said one or more operations for said input/output device, each of said one or more in-progress bits being set when said associated one of said one or more operations is initiated, and being cleared when said associated one or more operations is completed;
• providing one or more snapshot bits of equal number to said in-progress bits;
• copying, at said inquiry start time, all of the one or more in-progress bits to the corresponding one or more snapshot bits;
• clearing each of said one or more snapshot bits when said associated one or more operations is completed;
• and
• determining whether every one of said one or more snapshot bits is cleared.