CompuServe Messages

Phillip W may be overstating his case, but he has a point. Three 16-bit chips came out in roughly the same time frame: The Intel 8086, the Zilog Z80, and the Motorola 68000. Of the three, the Motorola chip had by far the best framework for future expansion: 68000 programs had the capability of using 24-bit addresses directly. The 8086, with its 64K instruction reach, was clearly the most crippled for the future: its instruction set was already overloaded. All three chips had architectures based on earlier 8-bit products. Intel had the clumsiest 8-bit product; heck, it had its origins in a 4-bit chip, and the history had gone 4004, 8008, to 8080. The 68000 was expanded to the '20, '30, '40 and '60 in a number of ways, but the improvements were largely in the area of new instructions and more addressing modes. The 8086, in contrast, was in a "64K blocked" mode, and major surgery had to be performed to unblock it. "Protected mode" is a clever idea, but it was also a radical change, and the MS-DOS operating system couldn't handle it. Even today, MS-DOS requires protected mode to be disabled when it takes over an operation. I've run across no such anomaly in the 680×0. From the 80386, newer intel chips have smooth upward compatibility; but the road from the 8086 to the 386 was a bumpy one indeed. The 68000 to 68060 path, in contrast, shows no comparable signs of retrofit. Intel had the most popular chip for small computer systems: a large part of that world ran on CP/M. When PC-DOS/MS-DOS came into place, it was a recut of CP/M, and couldn't shake loose from the intel chip line. It wasn't because the chip set was superior. Many people on this board would agree that technical superiority does not always assure leadership in the marketplace. –Jim