How fast is scsi 2

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SCSI-2 was released in with optional bit bus, unlike the original SCSI which was only 8 bits, and has more pins and device connection capacity.

The SCSI-2 interface is fast and efficient. It has a connection capacity of 16 or more devices, compared to 8 devices in the case of the original SCSI. All of these types differ in functionality and included features.

The grades are backward compatible, so as long as you have the connectors right, you can over-buy and be assured your chain will still work. Fortunately, there are only two styles of internal SCSI connectors for consumer devices, so your chances of getting it right are pretty good.

The only time you're likely to see the third type of connecter SCA is if you're working on a storage array with hot swappable drives. The following section assumes you know more jargon than is presented in the Basic section above, but you don't have to be an engineer to understand it.

If you feel you've understood everything up to this point without a hitch, keep reading. If your question wasn't answered in this section, check the Frequently Asked Questions at the bottom of the article. SCSI is an amazingly robust technology. It uses very little processor time, won't overload the system bus, the components it controls can run very fast, and it can control a great quantity of devices.

Why, then, do most home and office computers use a competing technology? First, a bit of history Using SCSI, the Macintosh world avoided all these problems and only required one bus to run all its devices. As data processing speeds increase, so do the demands for faster data transfer. This means that you can transfer 8 bits at a time, 5 million times a second. To increase the speed of data transfer, you can increase the width of the bus, increase the clock speed, or both.

This uses a separate pin on the cable to ensure accurate transfer. Why is SCSI so fast? People often dismiss the reason that SCSI is fast, and simply assume that it's faster than whatever technology their currently using. This is a set of signals that all SCSI devices must be able to understand the embellishments on this protocol such as Fibre Channel and the IEEE bus are outside the scope of this article.

This system allows a SCSI device to stream data from one device to another with a single command. The CD ROM could just as easily been told to send it's data to a hard disk, bypassing the controller and system bus entirely and saving a lot of bandwidth. These requests add up to a lot of data being needlessly transmitted on the bus. SCSI-2 is used with Personal Computers and computer Peripheral devices and includes command sets for magnetic and optical disks, tapes, printers, processors, CD-ROMs, scanners, medium changers, and communications devices.

SCSI-2 may be either a Single-Ended data bus transmitting data referenced to ground [unbalanced], or a balanced differential bus. Single-ended and differential devices are electrically incompatible and can not be mixed on the same physical bus [refer to the electrical description]. SCSI-2 asynchronous transfers would operate up to 1.

SCSI commands are sent at the asynchronous rate. The differential characteristics conform to the EIA interface standard. The Single-ended 'A' cable interface used a 50 pin Centronics connector, with a single-ended driver and receiver configuration which defined the maximum cable length of 6 meters.

The cable used may be either a conductor flat cable or signal twisted-pair cable. The pin out for the 'A' Single-ended data cable is listed below.

The 'B' cable uses a pin connector. A conductor flat cable or signal twisted-pair cable shall be used for the 'B' cable. The 'B' cable has a maximum length of up to 25 meters using differential drivers and receivers.