Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!cica!gatech!udel!mmdf
From: Leisner.Henr@xerox.com (marty)
Newsgroups: comp.os.minix
Subject: Re: C compilers in 286 protected mode. (was compress)
Message-ID: <20050@louie.udel.EDU>
Date: 19 Jul 89 18:52:13 GMT
Sender: mmdf@udel.EDU
Lines: 32

Having a C compiler which understands segmentation is part of the problem.

Having an operating system which understands segmentation is another
problem.

How does brk work on a segmented system?  Think about it.  The 286
malloc/brk systems are somewhat bizarre (compared to linear address space
machines).

I tend to think the 286 is a collossal blunder which is incredibly
difficult to deal with.  Xenix 286, MicroPort and Ms-Dos vendors have a
large market to target at of people who have 286 machines.  I spent a lot
of time with the 286 and kinda feel it wasn't worth it since to get take
advantage of the 286 hardware its hard to have a generic operating system.


I feel protected mode buys you significant OS features (well, protection
for one).

A mixed model C compiler in a non-linear address space just causes grief.

It would be relatively simple to generate large data model code with 1
code, 1 data, 1 stack segment -- on the surface this fits Minix'es memory
models but I found it would require extensive changes to the system to
implement (there is a implicit assumption S and D are in the same data
space and all messages are passed in D space).

marty
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