What is the computer hard drive interface?

The hard disk interface is a connecting part between the hard disk and the host system, which transmits data between the hard disk cache and the host memory. The different hard disk interface determines the connection speed between the hard disk and the computer, in the whole system, the quality of the hard disk interface directly affects the program running speed and performance.

General classification and large class classification

From the overall point of view, the hard disk interface is divided into IDE, SATA, SCSI and Fibre Channel Four, IDE interface hard disk for home products, but also partly applied to the server, SCSI interface of the hard disk is mainly used in the server market, and Fibre Channel only in high-end servers, the price is expensive. SATA is mainly used in the home market, there are SATA, sataιι, sataιιι, is now the mainstream; in the IDE and SCSI large categories, but also can be divided into a variety of specific interface types, and each have different technical specifications, with different transmission speed, such as ATA100 and SATA; ULTRA160 SCSI and Ultra320 SCSI all represent a specific hard disk interface, and their speed varies considerably.

HDD Interface Classification

Ide

IDE's English is all called "Integrated Drive Electronics", namely "Electronic Integrated Drive", the common 2.5-inch IDE hard disk interface It is meant to refer to "Hard disk controller" and "Disk body" integrated with the hard drive. The integration of the disk and the controller reduces the number and length of cables to the hard drive interface, enhances the reliability of the data transmission, and makes it easier to make the hard drive because the hard drive manufacturer does not need to worry about whether its hard drive is compatible with the controller produced by other manufacturers. For users, hard disk installation is also more convenient. IDE this interface technology from the birth has been constantly developing, performance has been continuously improved, its low-cost, compatible with the characteristics of strong, for its other types of hard disk can not replace the status.

The IDE represents a type of hard disk, but in practical applications, it is also customary to use the IDE to address the earliest IDE type hard disk ATA-1, a type of interface that has been eliminated with the development of interface technology and later branched out into more types of hard disk interfaces, such as ATA, Ultra ATA, Interfaces such as DMA, Ultra DMA, and so on are part of the IDE hard disk.

Scsi

SCSI is called "Small Computer system Interface" (Small computer system interface), SCSI interface is a completely different interface with IDE (ATA), the IDE interface is standard interface of normal PC, and SCSI is not the interface specially designed for hard disk , it is a kind of high-speed data transmission technology which is widely used in small machine. SCSI interface has a wide range of applications, multitasking, large bandwidth, low CPU usage, as well as hot Plug and so on, but the high price makes it difficult as the IDE hard drive, so the SCSI hard disk is mainly used in high-end servers and high-end workstations.

Fibre Channel

The English spelling of Fibre Channel is fibre Channel, same as the Scis interface. Fibre Channel was not originally designed for hard disk design and development of interface technology, is designed for the network system, but with the storage system on the speed of the need to gradually apply to the hard disk system. The Fibre Channel hard disk is developed to improve the speed and flexibility of the multi-disk storage system, and its appearance greatly improves the communication speed of the multi-disk system. The main characteristics of Fibre Channel are: hot-pluggable, high-speed bandwidth, remote connection, large number of connected devices.

Sata

SATA (serial ATA) port of the hard drive is also called serial hard disk, SATA hard disk interface is the future of PC hard drive trend. In the 2001, the Serial ATA Commission, made up of Intel, APT, Dell, IBM, Seagate and Serial, officially established the ATA 1.0 specification, and in 2002, although serial ATA related equipment was not officially listed, serial The ATA Commission has preempted the Serial ATA 2.0 specification. Serial ATA uses serial connection, the Serial ATA bus uses the embedded clock signal, has the stronger error correcting ability, compared to the past its biggest difference is can carry on the transmission instruction (not only the data) to examine, if discovers the error will automatically correct, this greatly enhances the data transmission reliability. The serial interface also has the advantages of simple structure and hot-swappable support.

Sataii interface

SATA II was developed on the basis of SATA, and its main feature was that the external transmission rate was further increased from SATA 1.5Gbps (150mb/sec) to 3Gbps (300MB/SEC), in addition to NCQ (Native Command Queuing , native command queue), Port multiplier, staggered start (staggered spin-up) and a series of technical features. Pure external transmission rate of 3Gbps is not true SATA II.

The key technology of SATA II is the external transmission rate and NCQ technology of 3Gbps. NCQ technology can optimize the instruction execution order of the hard disk, avoid moving the head to read and write the hard disk in the same order as the traditional hard disk, and in contrast, it will sort it after receiving the command, and the head of the sort will be addressed in an efficient order. So as to avoid the loss caused by repeated movement of the head, prolong the hard life. In addition, not all SATA drives can use the NCQ technology, in addition to the hard disk itself to support NCQ, also requires the motherboard chipset SATA controller support NCQ. In addition, the NCQ technology does not support the FAT file system, and only the NTFS file system is supported.