It might just be a reformatting procedure, but—
COMMON DEF T S$ VAR A$ LOAD S$,0OUT A$ STOP ENDEdit: added COMMON and removed space before OUT After you call T with a valid file extension and name within S$ (ex. "TXT:FILE") print the variable S$ on the console. The contents of the string have been modified as a result of the load instruction. If you print S$ during runtime, the anomaly does not occur. I'm not sure what the modified string characters are for, I can only guess that it's SB's way of converting the name and extension into something the file system can use.