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From: moraes@utcsri.UUCP (Mark A. Moraes)
Newsgroups: comp.os.minix
Subject: Re: Hardware Dependance
Message-ID: <4114@utcsri.UUCP>
Date: Wed, 11-Feb-87 08:27:11 EST
Article-I.D.: utcsri.4114
Posted: Wed Feb 11 08:27:11 1987
Date-Received: Wed, 11-Feb-87 20:43:52 EST
References: <275@ihnp3.UUCP> <459@moncol.UUCP> <2529@well.UUCP> <228@inuxf.UUCP>
Organization: CSRI, University of Toronto
Lines: 23

> > My apologies if this is a dumb question, by why the design decision to
> > make MINIX so hardware-dependant. Why wasn't the BIOS used? Does the
> > BIOS not provide enough functionality? If the problem is just speed,
> > why not write a slower version for those of us whose chips don't have
> > the right pedigree? The hardware dependance strikes at one of the
> > basic tentents of UNIX philosophy.
> > 
> > 
> > -- 
> > The opinions expressed are my own, but you're welcome to share them.
> > Harry Henderson (freelance technical editor/writer).
> 
> It seems to me that since MINIX was designed as an educational tool,
> it may have been thought to be more educational to be able to see actual
> driver code instead of a BIOS call using a software interrupt.  Not much
> to be learned there except the inefficiencies of MSDOS lower layers :-).

I suspect the main reason BIOS was not used is that it is
not re-entrant - at least 2.0 is not. That promptly makes
serious UNIX stuff impossible, or at least darn dificult!
It is probably much cleaner to start at the lowest level .

Mark Moraes.