Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!ncar!gatech!usenet.ins.cwru.edu!ncoast!allbery From: allbery@NCoast.ORG (Brandon S. Allbery KB8JRR/AA) Newsgroups: comp.sys.amiga.advocacy Subject: Re: 8-bit death Message-ID: <1991May10.003301.7881@NCoast.ORG> Date: 10 May 91 00:33:01 GMT References: <1991May3.041705.9907@kessner.denver.co.us> <1991May5.022646.19235@sugar.hackercorp.com> <1991May7.063757.804@kessner.denver.co.us> Reply-To: allbery@ncoast.ORG (Brandon S. Allbery KB8JRR/AA) Followup-To: comp.sys.amiga.advocacy Organization: North Coast Public Access Un*x (ncoast) Lines: 70 As quoted from <1991May7.063757.804@kessner.denver.co.us> by david@kessner.denver.co.us (David Kessner): +--------------- | In article <1991May5.022646.19235@sugar.hackercorp.com> peter@sugar.hackercorp.com (Peter da Silva) writes: | >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. | >> 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. | | So be it. But _you_ are the only one that wishes to bother talking about | CP/M, etc, etc. +--------------- Strictly speaking, it's the number of bits in the general registers/ accumulator. HL was not a general register. Actually, even more strictly speaking, it's proper to use a hybrid designator for the processors with more than one register size, thus the 8080, Z80, and 1802 (and 6809) are 8/16-bit registers. Of course, by this rule, so is the 80x86 (AH/AL)... and the 680x0 (XXX.B instructions). The largest general register disambiguates, thus AX makes the 80x86 16-bit and d0-d7 make the 680x0 32-bit. Except for the 68000 only addressing 24 bits of memory... "Bits" in this context is as meaningless as MIPS. Why fight over it? +--------------- | >> 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 was limited by a bad inital design. Early on, a lot of programmers | learned that the BIOS didn't do many things very well-- namely video/graphics, | serial I/O, and a few other things. Then there were many programmers that | insisted on going around the OS and access the hardware directly. The BIOS | cannot mask the hardware differences when the BIOS is not used. +--------------- Exactly. Take a look at the BIOS serial driver some time, and have a good laugh. The other problem is that when BIOS or DOS did manage to do what you wanted, it was dog slow doing it. +--------------- | You wanted to know why I thought of the BIOS as part of MS-DOS... And I | told you... +--------------- That's not why the BIOS is part of MS-DOS, it's why MS-DOS is such a miserable excuse for an OS. BIOS was intended as a platform on which MS-DOS or CP/M-86 could be implemented in a hardware-independent fashion by providing the most basic interface to the hardware; CP/M-86 never caught on, and MS-DOS performed so miserably, that programmers resorted to calling BIOS directly or even diddling the hardware itself. It's notable that, when programs *did* do things through MS-DOS, Concurrent CP/M's DOS compatibility mechanism could multitask them quite well... and just about all standard CP/M-86 programs could be multitasked as well, because fewer CP/M-86 programmers had to resort to BIOS or hardware to get things done. ++Brandon -- Me: Brandon S. Allbery Ham: KB8JRR/AA 10m,6m,2m,220,440,1.2 Internet: allbery@NCoast.ORG (restricted HF at present) Delphi: ALLBERY AMPR: kb8jrr.AmPR.ORG [44.70.4.88] uunet!usenet.ins.cwru.edu!ncoast!allbery KB8JRR @ WA8BXN.OH