|
SCSI - Small Computers System InterfaceGeneral information SCSI1, SCSI2 and SCSI3It was not cheap those days to buy such an interface adapter card: in 1981 I bought my HP-IB for 400 USD or so. Neither the attacheable devices were cheap (printers, plotters, data acquisitions units, etc.). The Small Computers System Interface, SCSI for short, pronounced "scuzy", was originally developed by IBM in the mid '80s, as far as I can remember. It was an 8-bit parallel interface designed to asynchronously operate some peripheral devices. SCSI was similar to the IEEE-488 8-bit, but cheaper, and soon became popular in the PC world. The SCSI specification, opposite to the well-defined IEEE-488 standard, was not standardized, and manufacturers starded producing SCSI devices uncompatible with SCSI interface cards from other manufacturers. The need for a standardization in the SCSI world became evident, and this event occurred at the beginning of the '90 when the SCSI2 standard was first introduced. The term SCSI1 was introduced as well, to designate all those SCSI equipments that were produced before the SCSI2 advent. SCSI2 is a true and robust standard, and a general description from the programmer's standpoint is given here. SCSI2 is not the end of the story. Technology has been advancing these years, faster and wider bus became possible, and new devices appeared on the market (like CD recorders and DVD recorders). This situation led to the evolution of the standard, that is now called SCSI3. A general introduction to the SCSI3 is given here. SCSI, fast-SCSI, wide-SCSI, ultra-SCSI, ultra-wide-SCSI
The information provided in this article is very basic. For detailed information the most comprehensive site to visit is the following: Gary Field's SCSI Info Central.
|