SCSI-180°DIP Section

Small computer system interface (SCSI) is an independent processor standard for system level interfaces between computers and intelligent devices (hard disks, floppy drives, optical drives, printers, scanners, etc.). SCSI is an intelligent universal interface standard.

1. SCSI can support multiple devices, SCSI-2 (fastscsi) can connect up to 7 SCSI devices, and widescsi-2 can connect 15 SCSI devices. In other words, all devices only need to occupy one IRQ. At the same time, SCSI also supports a wide range of devices, such as CD-ROM, DVD, CDR, hard disk, tape drive, scanner, etc.

2. SCSI also allows one device to transfer data and another device to look up its data. This can achieve higher performance in multitasking operating systems such as Linux and windows NT.

3. SCSI occupies a very low CPU, so it has obvious advantages in multitask system. Since the SCSI card itself has a CPU, it can handle all the transactions of SCSI devices. When the host CPU sends work instructions to the SCSI card, the SCSI card will work by itself. After the work is finished, the work results will be returned to the CPU. In the whole process, the CPU can carry out its own work.

4. The SCSI device is also intelligent. The SCSI card can queue CPU instructions by itself, which improves the work efficiency. In multitasking, the hard disk will be in the current head position, and the adjacent tasks will be completed first and then processed one by one.

5. The fastest SCSI bus has a bandwidth of 160MB / s, which requires the use of a 64 bit 66MHz PCI slot. Therefore, the maximum speed that can be achieved in the PCI-X bus standard is 80mb / s. if it is used with a dedicated hard disk with 10000rpm or 15000rpm, it will bring obvious performance improvement.