This article will introduce SCSI interface, including types, differences, and merits.
It is an intelligent and universal interface standard.
Characteristics
SCSI is an universal interface.
On the SCSI bus, the host adapter can be connected with 8 SCSI peripheral controllers.
SCSI is a multi-task interface with bus arbitration function.
Multiple peripherals hung on one SCSI bus can work simultaneously.
And SCSI devices have equal possession of the bus.
The connecting cable can reach 6 meters when SCSI interface is connected to external devices.
SCSI interface can transmit data synchronously and asynchronously.
The synchronous transmission rate reaches 10MB/s, and the asynchronously transmission rate reaches 1.5MB/s.
Types
SCSI-1
SCSI-1 is the oldest version.
Its asynchronous transmission frequency is 3MB/s, and the synchronous transmission frequency is 5MB/s.
If you use external equipment, none of the internal interfaces can be used.
(Namely all internal interfaces cannot be used.)
SCSI-2
Early SCSI-2 is called Fast SCSI.
The data transmission rate is promoted from original 5MB/s to 10MB/s by increasing the synchronous transmission frequency.
SCSI supports 8-bit parallel data transmission and 7 peripherals can be connected to it.
And later WideSCSI supports 16-bit parallel data transmission with a rate of 20MB/s and it can support 16 peripherals.
SCSI-3
SCSI-3 was born in 1995.
It is also called UltraSCSI, which had a faster synchronous transmission rate of 20MB/s.
If the 16-bit transmission Wide mode is adopted, the data transmission rate can be promoted to 40MB/s.
This SCSI version uses 68-pin interface and it is mainly used in keyboard.
SCSI-3 has many types.
Differences
Except for SCSI,IDEis also a commonly used interface.
In addition, IDE has high cost performance and wide range of applications, etc.
And this causes the limitation of the range of practical use.
