Hard disk interfaces

Three hard disk interfaces are common on today’s computers:

• PATA (Parallel Advanced Technology Attachment) – these interfaces used to be very common, but they are being replaced by SATA in newer systems. As the name implies, PATA disks use a parallel interface, which means that several bits of are transferred at once.  In Linux, PATA disks are identified as /dev/hda, /dev/hdb, and so on. Partitions are identified by numbers after the device name (e.g. /dev/hda1, /dev/hda2…).
• SATA (Serial Advanced Technology Attachment) – a serial version of the ATA protocol. As the word serial implies, SATA is a serial bus, which mean that only one bit of data can be transferred at a time. Unlike with PATA, a single cable can connect only one disk to the motherboard. Most Linux SATA drivers treat SATA disks as if they were SCSI disks and name them accordingly.
• SCSI (Small Computer System Interface) – a parallel interface that was once common on servers and high-end interfaces. Supports up to 8 or 16 devices per bus. In Linux, SCSI disks are identified as /dev/sda, /dev/sdb, and so on. Partitions are identified by numbers after the device name (e.g. /dev/sda1, /dev/sda2…).