MEM 0040h:0077h - FIXED DISK - I/O port offset {IBMInternational Busiuness MachinesInternational Busiuness Machines) A hardware, software and other service technology company founded in 1911. documented only for XTIBM PC XT} Size: BYTE SeeAlso: MEM 0040h:0075h"FIXED DISK",MEM 0040h:0076h"FIXED DISK"