From: furballs@sequent.com (Paul Penrod)
Newsgroups: comp.os.os2.advocacy,comp.os.ms-windows.advocacy
Subject: Re: FCC will proclaim Microsoft is run by Communists! : )
Date: 27 Dec 92 01:52:56 GMT
Article-I.D.: sequent.1992Dec27.015256.7567
Organization: Sequent Computer Systems, Inc.

In article <1992Dec25.163338.29576@tc.cornell.edu> bai@msiadmin.cit.cornell.edu (Dov Bai-MSI Visitor) writes:
>In article <1992Dec25.102400.13417@donau.et.tudelft.nl> linstee@dutecaj.et.tudelft.nl (Erik van Linstee) writes:
>
>>Well, I don't know anything about your FTC, and I don't quite get
>>what it has to do with software needing to know about systems
>>internals.
>>All I am saying is that software engineers needn't worry about
>>system internals. Only time critical software needs to grab an
>>interrupt and as regular software goes this would only be a
>>comm. package. And even then the designer needn't know about
>>the internals, because he can use a library that installs an
>>interrupt handler. Of course he can prefer to do it himself, as
>>I often do, but that is only because I choose not to use anything
>>I don't have total control over. this is of course only feasible
>>if you design a piece of software by yourself.
>>Summary: application designers need not worry about system internals,
>>thats what the systems the designers are for.
>
>Does not the DOS programmer need to know about segment:offset 
>addressing, what memory model to use, and when ? Can one program
>effectively on DOS without that knowledge ?
>

Yes, one can, as long as one understands the limitiations between
applications development in the true portable sense, and the
virtual machine layer that interfaces into the OS and hardware. XED
was ported to DOS this way. I know, I did the port. The
applications layer was completely unaware of DOS, and compiled to
run on 17 other UNIX platforms form the same set of source.

>How about the differences between 286/386 ?
>

see above...

>How about the 640k limit and how to overcome it ? Need not the 
>programmer know about extended/expanded memory, DPMI/VCPI interfaces ?
>I have in front of me the second edition (1992) of the book
>"Extending DOS - A Programmer's Guide to Protected Mode DOS" by
>Ray Duncan. The first introductory chapter include detailed description 
>of selectors, descriptors etc. 
>
see above... 

Also, there are libraries out there to handle these kinds of
things, including several very good ones on virtual memory
management that require little understanding of how DOS operates.

NOW, the real issues was:

Does Microsoft enjoy an advantage using undocumented calls in the
applications. Again I say NO. There is NO advantage to using
undocumented calls, when those calls can/will/and do change from
release to release of the OS, causing the application to break in
how every many spots those calls were issued from. This forces the
programmer to go back and change things once again, and maybe if
he's smart, figure out how it should be done using the documented
calls in the first place.

I tried this trick once years ago. I got bit.

I would rather spend my time in useful persuits, rather than fixing
something that never need fixing in the first place.

JMHO..

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