1. Chapter 6 Adding SCSI cards and Drives
Prepared by:
Khurram N. Shamsi

2. What is SCSI? SCSI is short for Small Computer System Interface.
The SCSI card controls various SCSI devices.
SCSI devices may be hard drives, optical discs, scanners or tape drives.

3. How SCSI works?
A SCSI card is inserted into a PCI slot inside the computer.
A SCSI card has its own processing chip and does not need to rely on the CPU (Central Processing Unit).
A SCSI card can link up to 15 devices per card.

4. Types of SCSI cards
There are various versions of the SCSI card that feature different connectors as the technology has evolved.
25-pin SCSI card
These controls original SCSI devices
50-pin SCSI card
These controls Narrow (8-bit) SCSI-2, FastSCSI, and Ultra SCSI devices
68-pin SCSI card
These controls Wide (16-bit) Ultra-Wide, Ultra2, Ultra 160, and Ultra 320 devices

5. Advantages of SCSI
Many people prefer SCSI to standard IDE as SCSI technology is much faster.
SCSI is commonly used in servers and industrial applications.
It is fast and more robust technology than IDE (Integrated Drive Electronics).
Wide range of applications are available.
Better flexibility for RAID (Redundant Array of Independent Disks).
Better for storing and moving large amount of data.
SCSI devices are designed to be used for 24/7 to address the needs of the server market.
SCSI devices are highly reliable.

6. Disadvantages of SCSI
The SCSI devices are more expensive then IDE devices.
SCSI devices are not widely supported.
There are different kinds of SCSI interfaces.
It is important to match the right SCSI controller to the desired SCSI components.
SCSI devices create more noise and heat.

7. Steps to Install SCSI devices
Shutdown your computer and disconnect all peripherals connected to it.
Unplug the power cables from the outlet.
Check if the SCSI cable you have has all connectors OK or if there are any bent pins.
The next step is to attach one end of the SCSI cable to the free SCSI connector of the device you want to connect and make sure the connector is firmly plugged in the SCSI port.
The last step in connecting a SCSI device is to connect the other end of the cable to the computer’s SCSI connector.
If the SCSI port is external you should be able to identify it easily on the rear of your computer based on the sise of the SCSI port that matches your SCSI cable.

8. Suggested Websites http://en.wikipedia.org/wiki/SCSI