To understand SATA, it is necessary to understand the early days of microcomputing. Back in the early 1960s, there were really only mainframes. A number of people made them; the industry was often referred to as “IBM and the Seven Dwarves.”
By the end of the Sixties, what were known as mid-range computers also came into existence; once again there were many manufacturers, though DEC had the same dominant position in mid-range computing as IBM had in mainframes. IBM did eventually get into the act, because it had to – an anti-trust suit was brought against it because, with its mainframe sales and its world-wide data centers, it was thought to be stifling fair competition. When it looked as though the result of the suit would be an order to sell its data center business, IBM decided that it could not send that division into the world without hardware and introduced a mid-range computer of its own – System/3.
Ultimately, IBM was not forced to divest its data center division and System/3 remained an IBM machine. As it had been expected to compete with IBM, the company had deliberately designed it to be totally non-compatible with the IBM 360 mainframe range and many of IBM’s later mid-range compatibility problems stem from that original decision.
While this was going on, however, something else was stirring in the computing world: the microcomputer. Although at first these were hobbyist devices, they rapidly gained a place in accounting functions and became big business. Once again, IBM had resisted getting involved; once again, they had to. They called their microcomputer the “Personal Computer” and from that moment all microcomputers were called PCs.
The AT was an early and very successful IBM PC; it replaced the previous parallel bus (a bus is not a motor vehicle; it’s the channel along which data is transferred) with a serial bus which it called the Serial AT Attachment – SATA for short; this newest bus took off and became widespread among manufacturers of microcomputers and peripherals; and so SATA was born.