Enhanced Small Disk Interface

Enhanced Small Disk Interface ( ESDI ) was a mass storage interface, which was invented in the early 1980s by the Maxtor Corporation as successor to the ST506 interface. ESDI shifted some components of the controller to the drive electronics, such as the Data Separator, and you generalized the control so that more additional devices could be controlled (such as a removable disk and tape drives). ESDI used the same cable as ST -506 ( a 34 -pin common control cable and a 20 - pin data cable for each drive ) and could therefore easily be used to replace an ST -506 application.

ESDI was in his mid to late 80's very popular because SCSI and ATA were still very immature and ST -506 was simply not fast enough. ESDI supported data rates of 10, 15, or 20 megabits per second ( whereas the maximum rate of ST -506 7.5 Mbps was ), many contemporary high-end SCSI drives were actually ESDI drives with a SCSI bridge in the drive electronics.

After the flexible usable SCSI was standardized in 1986 and ATA replaced the desktop area fast ST -506, ESDI lost rapidly in importance and, in the mid 90s as good as no longer used.

Pin assignment

• Peripheral bus (internal)