SCSI controller's English name is "Small Computer System Interface", as the name suggests, it is designed to expand minicomputer interfaces, and it allows the computer to install additional peripheral devices to improve system performance or add new features such as hard disks, optical drives, scanners and more.
According to speed and function, early computers are divided into large mainframes, minicomputers, microcomputers and so on. Some small workstations and servers belong to minicomputers, while personal computers belong to microcomputers. Therefore, the models that used the SCSI interface at the time were mainly middle and top grade equipment such as workstations and servers. In recent years, due to personal computer performance and demand have increased greatly, the application of SCSI in PC (ordinary microcomputer) is increased accordingly.
In fact, SCSI is not a new type of interface. It has gone through nearly 20 years since someone noticed the problem of function extension of minicomputers, started to develop a new unified expansion interface and formally set down the SCSI standard in 1986. Earlier, Apple (Apple Computer) took the lead in selecting SCSI as the standard Mac computer interface, and many peripherals adopted a unified interface to the main system. Because the expensive SCSI interface cards and devices, and almost all kinds of peripheral interfaces have less expensive alternatives in terms of PC, SCSI is not favored, relatively, there are not much SCSI devices available. In contrast, peripheral products that support the SCSI interface have been added to scanners, optical drives, recorders, MO and other devices from hard drives and tape drives. The opportunities for everyone to access SCSI are increasing; combined with the progress of manufacturing technology, the prices of SCSI cards and peripherals are no longer high which shows that the SCSI market is already quite mature.