Disk Controller in Computer Architecture

The disk controller moves the disk drive head, and reads, and/or writes data. Today, there are two types of disk controllers:

• IDE (integrated disk electronics)
• SCSI (small computer systems interface)

Integrated Disk Electronics (IDE): An IDE disk drive is connected to the ISA bus with a flat ribbon cable. The IDE disk controller supports two hard disks, each with a 528-megabyte capacity. In 1994, hard disk drive vendors introduced EIDE (extended IDE) which supports four devices, such as hard disks, tape drives, CD-ROM devices, and larger hard disk drives. The EIDE has two connectors. Each cable is connected to the EIDE controller and can support two hard disk drives with a capacity of up to 250 GB. EIDE is used in IBM-compatible computers.

Small Computer System Interface (SCSI): The small computer system interface (SCSI) standard is defined by the American National Standards Institute (ANSI) for connecting daisy-chaining multiple I/O devices, such as scanners, hard disks, and CD-ROMs, to the microcomputer, SCSI is a standard interface for all types of microcomputers. It is used in Macintosh, RISC workstations, and minicomputers, as well as in higher-end IBM-compatible computers. The SCSI bus comes with different types of controllers.

SATA (Serial Advanced Technology Attachment): SATA is a serial bus for connecting mess storage such as hard disk, optical drive, and solid-state drive to a computer.