ckp@grebyn.com (Checkpoint Technologies) (04/21/91)
In article <e1Gj02be06fI01@JUTS.ccc.amdahl.com> kls30@DUTS.ccc.amdahl.com (Kent L. Shephard) writes: >In article <16928@chopin.udel.edu> don@chopin.udel.edu (Donald R Lloyd) writes: >> Tell the millions of XT-clone users out there that the 8-bit market >>is dead. >>(Actually, IMHO, even a fast 486 qualifies as an 8-bit machine when it's >>running MS-DOS :-).~~~~~~~~~~~~~~~~~~~~~~~~ >~~~~~~~~~~~~~~~~~~~~ > >MS-DOS IS a 16 bit OS not eight bit. THe 8088 IS a 16 bit cpu with an >8 bit data bus. The 386sx is to the 386dx as a 8088 is to an 8086. >That is 16 bits vs 32 bits and 8 bits vs 16 bits. Now tell me that >a 386sx is a 16 bit cpu. How do we represent the number of "bits" for a microprocessor? The data bus for the 8088 is 8 bits wide. The registers are 16 bits wide. The ALU is 16 bits wide. The address bus is 20 bits wide. So is the 8088 an 8, 16, or 20 bit CPU? Most call it a 16 bit CPU, because of the ALU and programmer's model. The 68000 has a 16 bit data bus, 32 bit registers, 16 bit ALU, and 24 bit address bus. Most call it a 16 bit processor, even Motorola. However, the programmers model is one of a 32 bit CPU, given the registers and support for 32 bit arithmetic. So maybe it's really 32? The 68020 and 68030 have a 32 bit data bus, 32 bit registers, 32 bit ALU, and 32 bit address. Couldn't call them anything but 32 bit CPUs. The same can be said of the 386DX and 486. But the 386 and 486 are usually confined to "real mode" to run DOS, where the programming model is a 16 bit one. Even in Windows 3.0, the CPU is only switched to 16 bit protected mode. So the majority of the time, the 386 and 486 are just really fast 16 bit CPUs. The 386SX? Inside the case it's just a 386DX with some bus sizing options shorted so that only 16 data bits and only 24 address bits are brought out; theoretically it's really a 386DX. But think about what Intel is saying: you can buy the same silicon as the DX, but it's cheaper because it's been artificially constrained so it can't perform as well as the DX. I'll tell you what I call it: an insult to my intelligence. It shows what they *could* offer and what price they *could* ask, but won't. -- First comes the logo: C H E C K P O I N T T E C H N O L O G I E S / / ckp@grebyn.com \\ / / Then, the disclaimer: All expressed opinions are, indeed, opinions. \ / o Now for the witty part: I'm pink, therefore, I'm spam! \/