SIMON (Batch Interactive test/debug)

SIMON (Batch interactive test/debug) was a proprietary test/debugging toolkit for interactively testing Batch programs designed to run on IBM's System 360/370/390 architecture.

It operated in two modes, one of which was full instruction set simulator mode and provided Instruction step, conditional Program Breakpoint ("Pause") and storage alteration features for Assembler, COBOL and PL/1 programs.

High level language (HLL) users were also able to see and modify variables directly at a breakpoint by their symbolic names and set conditional breakpoints by data content.

Many of the features were also available in "partial monitor mode" which relied on deliberately interrupting the program at pre-defined points or when a "program check" occurred.In this mode, processing was not significantly different from normal processing speed without monitoring.

It additionally provided features to prevent application program errors such as Program Check, "Wild branch", and Program loop. It was possible to correct many errors and interactively alter the control flow of the executing application program. This permitted more errors to be detected for each compilation which, at the time, were often scheduled batch jobs with printed output, often requiring several hours "turnaround" before the next test run.

Operating systems

Simon could be executed on IBM MVS, MVS/XA, MVS/ESA or DOS/VSE operating systems and required IBM 3270 terminals for interaction with the application program.

Origin of the product name

The name SIMON was not an acronym (despite its suggestive connection to instruction SIMulatiON). In fact it was simply named after the writer's son, like its predecessor OLIVER!

See also

• Assembly language
• Batch programs
• Instruction Set Simulator for description of "full simulation mode"
• OLIVER (CICS interactive test/debug)
• SIMMON a similar tool, internal to IBM laboratories and written entirely independently