Hard Drive Types

Hard Drive Types

Listed below are commonly used Hard Drive Interfaces. 


Acronym or abbreviation Meaning Description
SASI Shugart Associates System Interface Historical predecessor to SCSI.
SCSI Small Computer System Interface Bus oriented that handles concurrent operations.
SAS Serial Attached SCSI Improvement of SCSI, uses serial communication instead of parallel.
ST-506 Seagate Technology Historical Seagate interface.
ST-412 Seagate Technology Historical Seagate interface (minor improvement over ST-506).
ESDI Enhanced Small Disk Interface Historical; backwards compatible with ST-412/506, but faster and more integrated.
(P)ATA (Parallel) AT Attachment Successor to ST-412/506/ESDI by integrating the disk controller completely onto the device. Incapable of concurrent operations.
SATA Serial ATA Modification of ATA, uses serial communication instead of parallel.
USB Universal Serial Bus Used for connecting external drives. An external drive enclosure can convert an internal drive to an external drive.
IEE1394 “Firewire” (Apple) or “I link” from Sony The theoretical speed of IEEE1394 is double that of USB 1.0.
SSD Solid-State drive Uses solid-state memory to store persistent data. An SSD emulates a hard disk drive interface, thus easily replacing it in most applications.