Newsgroups: comp.sys.amiga.advocacy Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!menudo.uh.edu!sugar!peter From: peter@sugar.hackercorp.com (Peter da Silva) Subject: Re: 8-bit death Message-ID: <1991May5.022646.19235@sugar.hackercorp.com> Organization: Sugar Land Unix -- Houston, TX References: <1991May1.064455.3058@kessner.denver.co.us> <21135@cbmvax.commodore.com> <1991May3.041705.9907@kessner.denver.co.us> Date: Sun, 5 May 1991 02:26:46 GMT In article <1991May3.041705.9907@kessner.denver.co.us> david@kessner.denver.co.us (David Kessner) writes: > IMHO, the 'bits' of an OS is the largest number it can put in a CPU register. I have never, in my experience, seen an O/S with registers. That's hardware. But then, if you wish: > In this light, MS-DOS is a 16 bit OS. Plain and simple. Same is true for CP/M. HL on the 8080 is 16 bits wide. IX and IY on the Z80 are too. Or how about MCP, the O/S I worked on in my last job... the 1802 has *16* 16-bit registers! That's 12 (or is that 13) more than the 8088. > Yes, I include the BIOS in the general scheme of MS-DOS. Microsoft doesn't. > Why? For several reasons: > The operating system (and/or device drivers) should deal with any > hardware differences between machines-- and that is the role of the > BIOS. That doesn't handle the differences between the IBM-PC, HP150, Victor 9000, TI-PRO, etc... or more recently the Data General 1... > The BIOS is highly standardized. In fact, they are (almost) > interchangeable between machines-- as long as the machines have the ...exact same bugs and features as the IBM-PC/XT or /AT (including crummy UARTS that don't support synchronous I/O)... > The BIOS plays just a large of a role in the MS-DOS world as MS-DOS > itself does. When you do application programming, you try to call > BIOS functions rather than MS-DOS functions (their faster, usually), > etc. I'm not discussing bugs and other implementation shortcoming in MS-DOS here. Just the software architecture. > And this makes it a 8 bit OS? Yes. The fact that it doesn't provide a hardware-independent application program interface for these resources. All an O/S is, at the bottom level, is a resource manager. So that's what I look at: what resources it manages and how complete the interface. > From the software point of view (which is the view MS-DOS has) the > 8088 and 8086 are identical (with a few very small differences) and are 16 > bits... No, they're a hybrid between 8-bit and real 16-bit CPUs. > I like how you said 'very similar' and not 'identical'. The 8088 should > be evaluated by it's own merits and not those of it's predicesors. Yes, and on those merits it really sucks. Motorolas 16/32 and 8/16 bit CPUs of the same era (68000, 6809) both blow it out of the water. > In the same, MS-DOS should be evaluated by looking at MS-DOS-- not CP/M. Why? CP/M was one of its competitors. > This is more of a function of the hardware than MS-DOS. Well look at the fate of computers that did a better job. If MS-DOS had been a real 16-bit O/S instead of a port of an 8-bit one the HP150, Victor 9000, TI PRO, and so on would have been successes. > (Damn Compatibility) Compatibility is only a problem if what you're compatible with causes problems. > Yes, and no. CP/M is more widely ported, true, and that's because of it's > early history in a time where there was not a lot of hardware standards-- > much like the history of UNIX. There were not a lot of hardware standards when the PC came out, either. > If you cant flame MS-DOS, who can you flame? Damn good question. -- Peter da Silva. `-_-' .