SCSI, SAS, FC, PATA, SATA, FATA Hard Disk Drives
SAN - NAS - DAS - iSCSI - HP XP Disk Array Family - HP Enterprise Virtual Array - HP Modular Smart Array - Disk Drive Types - D2D and VTL - Tape Libraries - CASThe two most common types of Disk Drives are Enterprise-class and Low-duty cycle drives. Enterprise-class drives are designed and manufactured for 24x7 I/O duty cycle, whereas Low-duty cycle (aka Desktop-quality drives) are designed and built for 20 to 30% I/O duty cycle. Each drive type can have one of many interfaces including:
- Enterprise-class Disk Drives:
- Parallel SCSI interface (PSI, aka SCSI)
- Serial-Attached SCSI (SAS)
- Fibre Channel (FC)
- Low-duty cycle Disk Drives:
- Parallel ATA (PATA)
- Serial-Attached ATA (SATA)
- Fibre Attached Technology Adapted (FATA)
- Parallel SCSI interface (PSI, aka SCSI) is one of the interface implementations in the SCSI family. In addition to being a data bus, SPI is a parallel electrical bus: There is one set of electrical connections stretching from one end of the SCSI bus to the other. A SCSI device attaches to the bus but does not interrupt it. Both ends of the bus must be terminated.
- Serial-Attached SCSI (SAS), an evolution of parallel SCSI into a point-to-point serial peripheral interface in which controllers are linked directly to disk drives. SAS is a performance improvement over traditional SCSI because SAS enables multiple devices (up to 128) of different sizes and types to be connected simultaneously with thinner and longer cables; its full-duplex signal transmission supports 3.0Gb/s. In addition, SAS drives can be hot-plugged.
- Fibre Channel Protocol (FCP) is the interface protocol of SCSI on the Fibre Channel. FC Drives are dual-port and include Native Command Queuing (NCQ) -a technology Native Command Queuing (NCQ) is a technology designed to increase performance of FCSATA hard disks under certain situations by allowing the individual hard disk to internally optimize the order in which received read and write commands are executed. NCQ is also built into certain SATA II and SCSI hard drives.
- Parallel Advanced Technology Attachment (PATA), a disk drive implementation that integrates the controller on the disk drive itself. This technology has been gradually replaced almost entirely by SATA since its market introduction in 2003.
- Serial ATA (SATA), an evolution of the Parallel ATA physical storage interface. SATA is a serial link -- a single thin cable with a minimum of four wires creates a point-to-point connection between devices. Transfer rates start at 150 MBps.
Contact Nth Generation today to learn more about when and where to use each type of hard disk drive with your Data Center applications.
- Fibre Attached Technology Adapted (FATA) is simply the low cost version of Fiber Channel hard drive in conjunction with ATA mechanism instead of SCSI. FATA can be considered as slower and less reliable than full-featured Fiber Channel hard drive although more reliable than desktop ATA drives and cost approximately half as much as regular FC drives per GB of capacity.