Abstract: A method for operating a computer to allow the running of a source program written for a first computer on a second computer. The second computer is assumed to include a branch taken trap. The method defines a plurality of collection points in the source program. A trap handling routine is supplied for processing traps. The trap handling routine determines whether execution has halted because of a branch taken trap at one of the collection points, and if so, retrieves information identifying an event from a queue and transferring the information and control to a handler in the source code. If execution has halted because of a branch taken trap at a location other than one of the collection points, execution of the source program is resumed with the branch taken trap armed. If execution has halted because of an asynchronous event, information specifying the event is stored in the queue, the branch taken trap is armed, and execution of the source program is resumed at the point at which execution was halted.