The MFIOP modules are the main I/O module of the CISC AS/400. They are tasked with SCSI control, real-time-clock tasks and in some cases floppy drive control.

FN2507

The FN2507 is the first iteration of the module and is employed by AS/400 computers of families B, C and D.

FN2615

The FN2615 is the last design of the module and is employed by AS/400 computers of families E and F.