11. MACHINE REQUIREMENTS
Basic FORSIM with room for 1000 equations requires about CM70000 (octal) to load and execute. As the user routines and any FORSIM library routines loaded will increase this slightly, default memory CM100000 (octal) (or CM parameter on job card absent) is recommended for use at CRNL.
For jobs with a large number of equations using the sophisticated Hindmarsh/Gear/Carver/Reid algorithm, more memory may be required. This presents no problem, as the first run is normally an exploratory trial, and FORSIM will report on how much memory is required. If insufficient job card field length is available, FORSIM will swith algorithms until a suitable one is found (Runge-Kutta will always run once the program is loaded).
For extremely large user routines, it is conceivable that the program will not even load. If such a possibility is expected, it is best to use the K parameter on the job card instead of CM. Kkkk, on the job card permits the job to use kkkk00 (octal) kiloword seconds during execution and allows it to occupy up to 300000(octal) CM until this KWS limit (CM*(T+IO)) is exhausted. FORSIM will report on required CM for the next run.