Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!psuvax1!rutgers!cbmvax!daveh From: daveh@cbmvax.commodore.com (Dave Haynie) Newsgroups: comp.sys.amiga.advocacy Subject: Re: 8-bit death (was Re: What the heck IS "Interactive TV"?) Message-ID: <20855@cbmvax.commodore.com> Date: 22 Apr 91 21:42:57 GMT References: <5967@mcrware.UUCP> <1991Apr15.020525.26370@mintaka.lcs.mit.edu> <16928@chopin.udel.edu> Reply-To: daveh@cbmvax.commodore.com (Dave Haynie) Organization: Commodore, West Chester, PA Lines: 35 In article kls30@DUTS.ccc.amdahl.com (Kent L. Shephard) writes: >In article <16928@chopin.udel.edu> don@chopin.udel.edu (Donald R Lloyd) writes: >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. That all depends on whether you're a hardware, software, or CPU architect type. From the software viewpoint, the '386SX is a 32 bit CPU with some hard modes restricted to 16 bit only operations (8086 and 80286 compatibility modes, for instance). The '486, and 68000->68040 all appear to be 32 bit systems from the software view. From the hardware view, the '386sx and 68000 are 16 bit CPUs, the '386DX, '486, and 68020->68040 are 32 bits CPUs, and the 8088 and 68008 are 8 bit CPUs. From the CPU architecture view, the 68000 is a 16 bit CPU with 32 bit registers. What difference does it all make? Depends on what you're doing. Since all 680x0s run 32 bit instructions, all 680x0 code can take advantage of a 32 bit bus, and therefore a 32 bit [hardware] CPU will go close to twice as fast as as a 16 bit [hardware] CPU, all else being equal. You get "close to", because some operations are only byte or word wide even on a 32 bit system. The same would apply to a '386sx versus '386dx, under UNIX or any other 32 bit OS. Thing is, who's running their PC in a '386 native mode? Not the vast majority of people out there, most things are 8088 emulation mode. So the '386sx was a clever idea on Intel's part -- it could run nearly as fast on most things as the '386 or AMD's speedy '286s, but for real '386 stuff, although it would be much slower, it would still work. > Kent -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "That's me in the corner, that's me in the spotlight" -R.E.M.