MFM is an acronym for Modified Frequency Modulation, which is a method of recording digital information on a magnetic medium of some sort, such as a tape or a disk by removing blank areas. The data-encoding scheme doubles the possibility of the storage that can be attained when compared to the previous recording technique used.
Technipages Explains MFM
Said recording technique was called Frequency Modulation or FM – while effective, MFM simply outdid it by a significant amount. A common misconception is that MFM refers to hard disk controllers that conform to a specific standard – the ST-506/ST-412. This is not true at all – it refers to the method used to get data on the disk and has nothing to do with disk interface standards like the ST-506. Instead, it’s a run-length limited or RLL encoding scheme that was mostly used on IBM-manufactured disks.
It was first released in 1970 and by 1976, it was one of the most common floppy disk encoding schemes out there. It was replaced reasonably quickly by more efficient RLL schemes and thus didn’t make the jump from floppy disk to physical hard drives very well, despite being used on a few early hard drive models. Although technically still in use, MFM is now obsolete except for a handful of specific disks that use that type of magnetic recording technology. More efficient multi-layer encryption mechanisms allowed for multiple times the storage at faster speeds on newer generations of hard drives and storage media.
Common Uses of MFM
- MFM is a type of encoding standard used commonly on IBM floppy disks.
- Although it is now outdated, it did pose a significant improvement over previous standards.
- MFM offers multi-layer data recording mechanisms
Common Misuses of MFM
- MFM refers to the hard disk controllers that follow the ST-506/ST-412 standard
