The average computer uses one of two hard drive types: ATA or SATA. However, there is another hard drive type that’s typically found only in high-end workstations and servers. This type of hard drive is called SCSI. The acronym SCSI stands for Small Computer System Interface. This type of hard drive is also affectionately known as “Skuzzy”. Just like ATA and SATA, SCSI can be utilized when connecting more than one hard drive to a specific computer system. Optical drives, printer,s tape drives, and scanners can all support SCSI.
SCSI standards were first introduced in the year 1986. This was also the same year ATA was released. Since that time, incredible advancements have been made to SCSI, particularly in the areas of bus width, speed, and connectible devices.
If you plan to connect your SCSI drive to a motherboard, you will be required to use an adaptor card, commonly known as a ‘host adaptor’. This adaptor serves as a data transfer gateway as opposed ot a processing center. System resources remain free during loaded data processing because of the SCSI controller. One bonus to these systems is that they ca operate while utilizing almost no PC power, they do so because SCSI drives offer direct communication. ATA and SATA drives all rely on the computer system itself to provide processing. This factors in more significantly when one takes into account the fact that one SCSI adaptor will support as many as fifteen other devices. This type of support could overwhelm a single controller if said controller was required to manage the communication for each of the devices.
Various drives connect to a computer system by the means of pin connection blocks. These blocks are often called ‘headers’ and can be located on desktop modem motherboards. These headers are utilized to support 40-pin ATA connectors or 7-pin SATA connectors. Because the SCSI is significantly specialized, you will only find built in adaptors on high-end motherboards. Depending on your computer’s age, the header may be equipped with 25, 50, 68, or 80 pins respectively. You may also consider the stand-alone variety of SCSI adaptor, which are readily available for PCI or PCI-X slots. These stand alone units can be chosen to match the available drives.
For an SCSI bus to identify all the devices within a system, each drive on the bus is required to have specific configuration and a unique value using the switches thereon. This unique value represents an SCSI ID, which translates into a number ranging between 0 and 15 on a 16 device capacity system.