A circuit that allows CPU to ‘interact’ with the hard disk, floppy disk or similar disk drive is called as the disk controller.
Earlier, the typical disk controllers were identified with the help of their storage methods as well as data encoding process as well. They were implemented on different controller card. MFM (Modified Frequency Modulation) controllers were commonly found in small computers, used for both hard disk as well as floppy disk drives. RLL (Run Length Limited) controllers made the use of data compression process to raise storage capacity by 50%, approximately. A proprietary storage algorithm that could recheck disk storage was designed and created by Priam. SASI (Shugart Associates Systems Interface) acted as SCSI’s predecessor.
Currently, the modern disk controllers are fixed into disk drive. For an instance, disks known as ‘SCSI disks’ currently have SCSI controllers that are built in. Earlier, before most of the SCSI controller functions were implemented in a single chip, different SCSI controllers were used to interface disks to the bus of SCSI.
At present, PATA (IDE) as well as Serial ATA for home purposes are the most commonly found types of interfaces found. Various high end disks use SCSI, Serial Attached or Fibre Channel SCSI. Flash memory timing access can be controlled with the help of disk controllers. This flash memory is not mechanical in nature at all (which means it is not a physical disk).