Abstract: The invention provides a method and apparatus for logging all references to microstore addresses irrespective of the number of times that a same address is referenced and irrespective of the order in which addresses are referenced. It provides a log indicating simply whether each address of the microstore has or has not been referenced within a prescribed time period. There is no limit placed on the duration of the prescribed time period and thus logging can cover long-term events such as, the full execution of a single macro-instruction, the full execution of an assembly level routine or the execution of all micro-instructions resident in the microstore as they are subjected to all possible input parameters. A practical tool for global visualization of computer operations is therefore provided.

Abstract: A conditional trace system in a computer system for controlling the enablement of a trace operation in the computer system, the computer system including a set of instructions for operating said computer, the set of instructions including branch instructions, the branch instruction generating a jump signal whenever the branch instruction performs a branch operation, the conditional trace system comprising a conditional trace field in each branch instruction where the conditional trace field has either a first or second value and a first means responsive to the value of said conditional trace field and the jump signal for selectively enabling and disenabling the trace operation within the computer system.