sion not to write its own PC operating system. Eventually it did do so - OS/2.The IBM PC was based on Intel's 8088 processor, which was released in 1980. The 8088 was a 16-bit processor which had 8 registers, about 100 instructions, and an unusual (some would say brain damaged) segmented 20-bit memory architecture capable of addressing 1 Mb of memory. It ran at a clock speed of 4.77 MHz in the original IBM PC. The 8088 was actually the second x86 processor. Its predecessor, the 8086 (released in 1978), used 16-bit external busses, whereas the 8088 used 8-bit busses. This made the 8088 about 20% slower than the 8086, but 8-bit busses were critical to keeping down the total system cost.IBM's decision to use the x86 architecture was widely criticized, and lead to the PC and its descendants facing many problems that other machines didn't face, mainly because of the x86's segmented memory model. So why did IBM chose the 8086 series when alternatives such as the Motorola 68000 were so much better? Apparently IBM's own engineers wanted to use the 68000, but IBM had already obtained the rights to manufacture the 8086 (for use in its Displaywriter intelligent typewriter), in exchange for giving Intel the rights to its bubble memory technology. Another factor was that the 8088 could use existing low cost 8-bit components, whereas 68000 components were more expensive and not widely available at that time. In any case, thanks to the PC's open design, the Intel x86 architecture went on to completely dominate the computing industry - proof that technical superiority sometimes doesn't matter.Graphical User Interfaces Arrive - The Xerox AltoIn the late 1970's and early 80's, the Xerox Alto started the graphical user interface revolution which would sweep through the computer industry over the following decade. The desk-sized Alto, and its commercialized descendant the Xerox Star, were the first GUI-based computers. Researchers at Xerox PARC (Palo Alto ...
