Lessons on Converting Batch Systems to Support Interaction

Software often evolves from batch to interactive use. Because these two usage styles are so different, batch systems usually require substantial changes to support interactive use. Specific issues that arise during conversion include assumptions about duration of system execution, incremental and partial processing, scope of processing, unordered and repeated processing, and error handling. Addressing these issues affects the implementation in the areas of memory management, assumptions and invariants, computational organization, and error handling. We use as a working example our conversion of the batch processor for the UniCon architecture description tool into an interactive architecture development tool. To capture the lessons for practitioners undertaking this type of conversion, we summarize with a checklist of design and implementation considerations.