Date: Thu, 31 May 2007 09:22:38 -0400 From: Mike Meyer <mwm-keyword-freebsdhackers2.e313df@mired.org> To: rmgls@wanadoo.fr Cc: freebsd-hackers@freebsd.org Subject: Re: direct I/O access Message-ID: <18014.52254.333433.704250@bhuda.mired.org> In-Reply-To: <20070531084755.816A61C0008F@mwinf1907.orange.fr> References: <20070531084755.816A61C0008F@mwinf1907.orange.fr>
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In <20070531084755.816A61C0008F@mwinf1907.orange.fr>, rmgls@wanadoo.fr typed: > On Wed, 30 May 2007 12:39:10 -0400, Mike Meyer <mwm-keyword-freebsdhackers2.e313df@mired.org> wrote, > > > Actually, protected mode is just the beginnings of it. I've never done > > much x86 assembly, but going from the '020 to the '030 (or maybe it > > was the '010 to the '020). I had to start invalidating the hardware > > caches after certain operations. After that, I switched to RISC > > hardware, which were designed assuming that the real people writing > > assembler would be few and far between, and did crazy things like > > rearrange the instruction sequence behind your back and add extra > > instructions. Modern systems do this kind of stuff as well. > > do you think that it would be better to rewrite the soft in C??? > in this case, i have more work to do! > first of all, learning C on the finger tip, before working on my soft. > > and i thought that it would be very interesting to learn > the heart of FreeBSD. Well, if you want to learn "the heart" of FreeBSD, I think you'd be better off working in C. The code that isn't part of FreeBSD on pretty much every platform would seem to be disqualified as the heart. > > This really is a kludge, though. You haven't said what you're trying > > to do. If you're trying to keep an old one-of device working, this is > > probably the best way. But if it's a real device that other people > > might be using, then writing a real device driver, or seeing if you > > can make the device work with something like the iic drivers might be > > better. > > in fact, they are: > - a direct to disk recorder, > - a sampler. > > they are not usable by other people, because they were discontinued. So nobody else has them? You can't pick one up used on eBay? I personally tend to run all but my most critical servers on "discontinued" hardware. It's fast enough to do the job running FreeBSD, and reasonably reliable; it's just not fast enough to run modern versions of Windows. And I can buy a system and a hot spare for a fraction of the cost of a new system. <mike -- Mike Meyer <mwm@mired.org> http://www.mired.org/consulting.html Independent Network/Unix/Perforce consultant, email for more information.
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