Hard disk: interface type

The hard disk interface is the connecting part between the hard disk and the host system, which is used to transfer data between the hard disk cache and the host memory. Different hard disk interfaces determine the connection speed between the hard disk and the computer. In the whole system, the quality of the hard disk interface directly affects the running speed of the program and the system performance. On the whole, hard disk interfaces are divided into four types: IDE, SATA, SCSI and Fibre Channel. IDE interface hard disks are mostly used in household products, but also partially used in servers. SCSI interface hard disks are mainly used in the server market, while Fibre Channel is only used in high-end servers, which is expensive. SATA is a new type of hard disk interface. It is still in the stage of market popularization and has a broad prospect in the home market. Under the IDE and SCSI categories, there are many specific interface types, with different technical specifications and transmission speeds, such as ATA100 and SATA; Both Ultra160 SCSI and Ultra320 SCSI represent a specific hard disk interface, and their speeds differ greatly.

IDE
The full English name of IDE is "Integrated Drive Electronics", that is, "Electronic Integrated Drive". It is intended to refer to the hard disk drive that integrates "hard disk controller" and "disk body" together. The integration of the disk body and the controller reduces the number and length of cables for the hard disk interface, enhances the reliability of data transmission, and makes hard disk manufacturing easier, because hard disk manufacturers no longer need to worry about whether their hard disks are compatible with the controllers produced by other manufacturers. For users, hard disk installation is also more convenient. IDE, an interface technology, has been constantly developing since its birth, and its performance has also been constantly improved. Its low price and strong compatibility have created its irreplaceable position for other types of hard disks.

IDE represents a type of hard disk, but in practical applications, people are also accustomed to using IDE to refer to the earliest IDE type hard disk ATA-1. This type of interface has been eliminated with the development of interface technology, and since then more types of hard disk interfaces have been developed, such as ATA, Ultra ATA, DMA, Ultra DMA and other interfaces belong to IDE hard disk.

SCSI
The full English name of SCSI is "Small Computer System Interface", which is a completely different interface from IDE (ATA). IDE interface is the standard interface of ordinary PC, while SCSI is not an interface specially designed for hard disk, but a high-speed data transmission technology widely used on minicomputers. SCSI interface has the advantages of wide application range, multitasking, large bandwidth, low CPU utilization, and hot plug, but the high price makes it difficult to popularize like IDE hard disk, so SCSI hard disk is mainly used in middle and high-end servers and high-end workstations.

Fibre Channel
The English spelling of Fibre Channel is Fibre Channel. Like SCIS interface, Fibre Channel is not an interface technology originally designed for hard disks, but is designed specifically for network systems. However, with the speed requirements of the storage system, it is gradually applied to hard disk systems. Fibre Channel hard disk is developed to improve the speed and flexibility of multi hard disk storage systems. Its appearance has greatly improved the communication speed of multi hard disk systems. The main characteristics of Fibre Channel are: hot pluggable, high-speed bandwidth, remote connection, large number of connecting devices, etc.

Fibre Channel is designed for multi hard disk system environments such as servers. It can meet the requirements of high-end workstations, servers, mass storage subnetworks, and peripherals for bidirectional and serial data communication through hubs, switches, and point-to-point connections.

SATA
The hard disk using SATA (Serial ATA) port is also called serial hard disk, which is the trend of PC hard disk in the future. In 2001, the Serial ATA Committee composed of Intel, APT, Dell, IBM, Seagate and Maxtor formally established the Serial ATA 1.0 specification. In 2002, although the related equipment of Serial ATA has not been officially launched, the Serial ATA Committee has established the Serial ATA 2.0 specification first. Serial ATA adopts serial connection mode. Serial ATA bus uses embedded clock signal, which has stronger error correction capability. Compared with the past, its biggest difference is that it can check transmission instructions (not only data). If errors are found, they will be automatically corrected, which greatly improves the reliability of data transmission. The serial interface also has the advantages of simple structure and hot plug support.

Serial hard disk is a new type of hard disk interface completely different from parallel ATA. It is well-known for its serial data transmission. Compared with parallel ATA, it has many advantages. First, Serial ATA transmits data in a continuous serial manner, and only 1-bit data is transmitted at a time. This can reduce the number of pins of SATA interface, reduce the number of connecting cables, and improve the efficiency. In fact, Serial ATA can complete all the work with only four pins, which are respectively used to connect cables, connect ground wires, send data and receive data. At the same time, this architecture can reduce system energy consumption and reduce system complexity. Secondly, Serial ATA has a higher starting point and greater development potential. The data transmission rate defined by Serial ATA 1.0 can reach 150MB/s, which is higher than the maximum data transmission rate of 133MB/s that can be reached by the latest parallel ATA (ATA/133). The data transmission rate in Serial ATA 2.0 will reach 300MB/s, and eventually SATA will achieve the maximum data transmission rate of 600MB/s.