From:	Brian Luczkiewicz <luczkiew AT acsu DOT buffalo DOT edu>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: **MAKING OS**
Date:	Tue, 20 Jul 1999 13:46:18 -0400
Organization:	University at Buffalo
Lines:	33
Message-ID:	<7n2cia$jjr$1@prometheus.acsu.buffalo.edu>
References:	<7mt7ta$52f$1 AT ionews DOT ionet DOT net>
NNTP-Posting-Host:	ubppp233-150.dialin.buffalo.edu
X-Newsreader:	Microsoft Outlook Express 4.72.2106.4
X-MimeOLE:	Produced By Microsoft MimeOLE V4.72.2106.4
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

I have made afew attempts at this myself (with little, but some luck). I
don't think it would be impossible for it to run under dos, but for it to
stand alone, you usually need to set up interrupts (anything above 0x20 is
ok). This is difficult (if not impossible) in c++, so I would recommend
assembler for at least the IDT and the GDT. DJGPP should be good, but you
won't be doin' very much printf-ing until you rewrite the standard library
to use bios functions. There are also a few things you should set down for
yourself ahead of time:

Protected mode or not? (DOS is not. DOS runs in real mode)
Multitasking or not?
Real Time or not?
Multithreaded or not?
Networkable or not?

The list can go on. Try to find the linux kernel sources for v0.01
(kernel.org has 'em in the historic directory). They make for good reading,
even though they have a tendency to be a little bit hacked over in some
places. (Such as the interrupt handler that does one thing, print to the
screen "Undefined Interrupt").

-Zorr


IOnet News wrote in message <7mt7ta$52f$1 AT ionews DOT ionet DOT net>...
>I am trying to write my own o/s in c++, i really dont know where to start.
>I am an advanced c++ programmer but never tried an OS.  any help would be
>great.  I want it to run under dos maybe, but not for sure.   It would be
>good if it could run all on its own
>
>

- Raw text -