For the server or workstation, SCSI hard disk is the undoubted choice. SCSI (Small Computer System Interface) is a widely used interface specification, which can connect hard disks, optical drives, printers, scanners, tape drives and other devices. It can be called another control core besides CPU in the system. Compared with the common IDE hard disk, SCSI hard disk has many advantages.
First, the SCSI interface has a higher transmission rate. At present, the latest IDE interface specification can reach the transmission speed of 133MB/s, while the SCSI interface increases the peak bandwidth to 320mb/s; In the corresponding hard disk technology, IDE products obviously lag behind SCSI products. Take Seagate's two representative products as an example. Barracuda IV is one of the best IDE hard disks at present, with a rotation speed of 7200rpm, an average data transfer rate of about 34MB/s, and a seek time of over 15 ms,-Cheetah X 15. It is the best SCSI hard disk, reaching 15000rpm and an average data transfer rate. ..
Secondly, another advantage of SCSI hard disk is its low CPU utilization. PIO working mode was adopted in the early IDE hard disk. During data transmission, the CPU utilization rate basically reaches 100%, and other operations cannot be carried out at all. The emergence of DMA technology has solved this problem to some extent. CPU does not need to monitor the whole process of data transmission, but it still occupies high system resources. However, SCSI devices do not have this problem. The CPU only needs to send data transmission instructions to the SCSI control chip, and does not participate in data processing and calculation. This feature is especially suitable for occasions where I/O operations are frequent or large-capacity file exchange is often involved, so it is widely used by servers and workstations.
In addition, SCSI has many advantages, such as rich expansibility, high error correction ability and higher intelligence when multitasking. Nevertheless, the high price still restricts the development of SCSI hard disk, which is far less popular than ordinary IDE hard disk and can only be applied to some high-end servers and workstations.