Starte Precision Electronic Co., Ltd

Professional Electronic peripheral cable and cable assembly manufacturer!

Home > News > Content
SCSI Hard DIsk Mode And Advantages
- Sep 18, 2018 -

Medium and high-end servers generally use SCSI hard disks. The most intuitive advantage of SCSI hard disks is fast and stable, and have an unparalleled advantage over PATA and SATA. Although with the advancement of technology, higher-speed SATA hard drives have begun to appear in the high-end market, SCSI has an unparalleled advantage in terms of millions of hours of trouble-free operation. So SCSI hard drives are still the most appropriate choice for enterprise applications.

Definition of SCSI Hard Disk

SCSI (Small Computer System Interface) is a storage unit interface mode designed for small computer systems. It can dynamically divide multiple devices in a computer, and can appropriately allocate multiple tasks required by the system at the same time. Dynamically completed.

The SCSI specification has evolved to the sixth generation, from SCSI (8bit), Wide SCSI (8bit), Ultra Wide SCSI (8bit/16bit), Ultra Wide SCSI 2 (16bit), Ultra 160 SCSI. (16bit) to today's Ultra 320 SCSI, the speed from 1.2MB / s to the current 320MB / s has a qualitative leap. The current mainstream SCSI hard drives use the Ultra 320 SCSI interface, which provides an interface transfer speed of 320MB/s.

Advantages of SCSI Hard Disk

1. SCSI Hard Disk can support multiple devices. For example, the ultra 320 can connect 15 hard disks to a single channel, and the dual channel can connect 30 SCSI devices. In other words, all devices only need to occupy one irq (interrupt request).

2. SCSI also allows data to be transmitted to one device while another device performs data look-ups, which results in higher performance in multitasking operating systems such as Linux and Windows NT.

3. The CPU usage of SCSI devices is extremely low, and it does have a clear advantage in multitasking systems. Since the SCSI card has a processor, it can process all the data of the SCSI device. When the host CPU sends a work command to the SCSI card during operation, the SCSI card will work by itself, and return the work result to the CPU after the work ends.

4. SCSI devices are also intelligent, and the SCSI card itself can queue CPU instructions, which improves 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.

SCSI hard disk interface mode:

At present, there are two types of SCSI mainstream interfaces, 68-pin and 80-pin (there are 50-pin interfaces in the early stage). The main difference is the market positioning. The 68-pin is for general users and the 80-pin is for hot-swap function for more advanced disk applications. There is no difference in performance between the two. The SCA2 interface (80-pin), which supports hot plugging technology, can be easily used for hot plugging with the SCSI backplane. Currently, hot plugging is almost a must in workgroup and departmental servers. of.

In addition, Fibre Channel is also used as a SCSI hard disk interface in high-end server/workstation hard drives. Fibre Channel is a high-performance connectivity standard for bi-directional, serial data communication between servers, mass storage sub-networks, and peripherals through hubs, switches, and point-to-point connections. Fibre Channel provides remote connectivity and high-speed bandwidth for the need to efficiently transfer large amounts of data between servers and storage media. It is ideal for storage area networks, clustered computers, and other data intensive computing facilities. Its interface transmission speed is divided into 1GB and 2GB and so on.

IBM Ultrastar 36Z15 Ultra-160 SCSI 80-Pin 4Mb Cache 3.5-Inch Internal Hard Drive (HDD)

IBM IC35L036UCPR15-0 Ultrastar 36Z15 Ultra-160 SCSI 80-Pin 4Mb Cache 3.5-Inch Internal Hard Drive

HP BD1468A4C5 146,8 GB 10K U320 SCSI 3.5" HDD con SCA a 68 pin Adattatore 90 RTB

HP BD1468A4C5 U320 SCSI 3.5 inch HDD con SCA a 68 pin