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From: dacut@henry.ece.cmu.edu (David A. Cuthbert)
Subject: Re: Is this ground dead?  Also, info on Mach that's more recent
Date: 1998/01/17
Message-ID: <69rdmb$j29$1@encore.ece.cmu.edu>#1/1
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References: <34AE2AE8.ED17B2C6@gildea.net>
 <5lzpky66rq.fsf@tequila.systemsz.cs.yale.edu>
 <69jr4q$44j$1@encore.ece.cmu.edu> <tgmEMy5z4.9vs@netcom.com>
Organization: Electrical & Computer Engineering, Carnegie Mellon University
Reply-To: henry.ece.cmu.edu!dacut
Newsgroups: comp.os.mach,comp.unix.bsd.misc,comp.lang.ada
Date: 1998-01-17T00:00:00+00:00
List-Id: <comp.lang.ada>


Thomas G. McWilliams <tgm@netcom.com> wrote:
>David A. Cuthbert <dacut@henry.ece.cmu.edu> wrote:
>: At any rate, relying on type safety for protection means that you
>: can't use C, C++, or assembly, or anything written in those
>: languages (so forget device drivers).  Assembly is the killer here;
>
>Have you used Ada?  Ada is type-safe and more powerful than C for
>low level bit-twiddling. Ada is a natural for device drivers and
>systems programming.

Used, no; glanced at code samples, yes.  My impression is that it
looks rather neat (nicer than C++ in many respects), but I've invested
too much into my C++ tools to even consider a switch.

I'm somewhat confused as to how Ada can be "natural" for device
drivers and systems programming.  For example, how do I code a task
switch or set up a DMA channel to a device in Ada?  Relying on a
library written in anything but Ada doesn't count.

Of course, I have no idea how I'd do that in C or C++, either, without
relying on nasty tricks like relying on assumptions about the
compiler's code generation and purposely breaking the type system.

-- 
David A. Cuthbert (dacut@ece.cmu.edu)
Graduate Student    Electrical and Computer Engineering
Data Storage Systems Center, Carnegie Mellon University