⟩ What is the significance of above the line and below the line?
Before IBM introduced MVS/XA architecture in the 1980’s a program’s virtual storage was limited to 16 Megs. Programs compiled with a 24 bit mode can only address 16 Mb of space, as though they were kept under an imaginary storage line. With COBOL II a program compiled with a 31 bit mode can be ‘above the 16 Mb line. (This ‘below the line’, ‘above the line’ imagery confuses most mainframe programmers, who tend to be a literal minded group.)