From: barrett@iastate.edu (Marc N Barrett)
Subject: Re: Amigas are cool
Organization: Iowa State University, Ames, IA
Date: Mon, 27 Jul 1992 14:08:38 GMT

In article <1992Jul26.220004.924@msus1.msus.edu> lkoop@TIGGER.STCLOUD.MSUS.EDU writes:
>In article <1992Jul26.213033.7016@news.iastate.edu>, barrett@iastate.edu (Marc N Barrett) writes:
>>In article <1992Jul26.190744.12857@cheshire.oxy.edu> leavitt@cheshire.oxy.edu (Thomas VanNess Leavitt) writes:
>>>Just curious... is AmigaDOS 2.0 a 32 bit OS?
>>
>>   I am not completely certain what is meant by "32-bit OS", but I know that
>>much of Intuition and the graphics.library are strictly limited to 8 bitplanes.
>>The equivilents to Intuition and graphics.library under MacOS, Windows, and
>>OS/2 are clean 32-bit designs.
>
>Marc,
>   You are confusing the issue here.  Though that is not suprising given that
>the terms "32-bit OS" and "32-bit application" are not really defined well.
>In the root case, you can consider an application or OS to be 32-bit compliant
>when it is capable of taking advantage of a 32-bit microprocessor design, and
>does not have hold-over problems from 16-bit setups.  Such is the case with
>applications which might use the upper bits of an address to hold data -- this
>was no problem on a 68000 with a 24 bit address space, but fatal on the full
>32-bit 68020 and above (Microsoft Amiga Basic did something similar to this -
>part of the reason it does not work very well under 68020+ based Amigas without
>patching).
>   MS-DOS would probably not be called a 32-bit DOS as it is given memory
>restraints even in a 32-bit environment.  I would classify AmigaOS as a 32-bit
>design as it can effectively deal with and take advantage of a 32-bit
>environment.  The bitplane allotment in the system display parameters does
>not dictate this judgement.  That is a seperate subsystem in which the OS
>is dealing with the hardware it has access to.  You would not call an operating
>system to be 'non 32-bit' simply because it has to deal in smaller quantities
>when accessing a 16-bit peripheral.

   As you can probably expect, I disagree.  I see no reason why the graphics
system should not be included in the definition of whether or not an OS is 
truly "32-bit".  You are excluding it mainly out of convenience.  If it were
the other way around, and the Amiga had an OS that was 32-bit throughout and
Windows and OS/2 used graphics systems that were limited to 8-bits, I am pretty
sure you would not be excluding the graphics system from the definition.

   Besides, Inuition and graphics.library are limited to 8-bits for many of
the same reasons that old MS-DOS and MAC programs will not run in a 32-bit 
environment.  Many of the calls in graphics.library are to routines like 
Write8Pixel and Read8Pixel; these routines use bytes, and not long-words, and
cannot be adapted easily to graphics systems with more than 8 bitplanes.  About
the only thing that Commodore can do is to add new routines like Write32Pixel
and Read32Pixel that new programs can use, though this will not help old programs
that use the old routines.  

>                   ----------------------------------------
>             LaMonte Koop -- SCSU Electrical/Computer Engineering
>  Internet: lkoop@tigger.stcloud.msus.edu -OR- f00012@kanga.stcloud.msus.edu
>               "You mean you want MORE lights on this thing???"
>  ---------------------------------------------------------------------------

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| Marc Barrett -MB-  |  email: barrett@iastate.edu
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