Access and Interfaces

During the history of a long drive, he uses many types of interface. We used ST-506 interface, still using the method of encoding data Modified Frequency Modulation (MFM). A data encoding is also used on floppy disks. Data transfer rate capable generated by this interface is 5 Mbps (Mega bits per second). Then slightly increased with use of 2.7 RLL encoding method, to reach the number of data transfer rate of 7.5 Mbps.

In Enhanced Small Disk Interface (ESDI), supports the use of multiple data rates. Hard disk and automatically adjusts the controller, in accordance with the attached device. Data transfer rate is able to produce 10, 15 and 20 Mbps. Initially, the SCSI is a rapid transfer rate, which is 5 Mbps. Then This single interface that dramatically increases. In the device interface to this, there is no limits. The use of buffers, both at the SCSI bus controller, or also on the drive it self, allows this. ATA drives have the advantage of the integrated controller. Initially made little problem with compatibility. Especially in the configuration master / slave, where two drives are connected with a data cable.

This problem is resolved in the 1990s, when the ATA began to standardized specifications. Although there is still a problem, when incorporating the device DMA (direct memory access) and non-DMA. Serial ATA eliminates the master and slave configuration. Each drive is served by a single-channel I / O exclusively, with a data cable.

Alternative use of FireWire / IEEE 1394 and USB (1.0/2.0) is also becoming known lately. Actually, in the device is an ATA or SATA drives, which added to the adapter interface to USB or FireWire. Besides can be used externally, this alternative is also used because of its simplicity. No need to add a port or hard disk controller card, if the number of available ports is no longer sufficient.