INT 2F - SWELL.EXE - INSTALLATION CHECK AX = CD00h Return: AX = 00FFh installed BH = major version BL = minor version Program: SWELL.EXE is a TSR(Terminate and Stay Resident) A program which remains in memory after terminating in order to provide services to other programs or the user. The name comes from the name of the DOS function call used to remain in memory after termination. which swaps programs to disk when they EXEC a child process with INT 21/AH=4Bh