From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262290AbVF2BJv (ORCPT ); Tue, 28 Jun 2005 21:09:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262275AbVF2BJp (ORCPT ); Tue, 28 Jun 2005 21:09:45 -0400 Received: from smtp04.mrf.mail.rcn.net ([207.172.4.63]:28487 "EHLO smtp04.mrf.mail.rcn.net") by vger.kernel.org with ESMTP id S261389AbVF2BI4 (ORCPT ); Tue, 28 Jun 2005 21:08:56 -0400 X-IronPort-AV: i="3.93,240,1115006400"; d="scan'208"; a="52944245:sNHT25078792" Subject: Re: Newbie Roadmap? From: Howard Owen To: Horst von Brand Cc: LKML List , Eric Smith In-Reply-To: <200506282141.j5SLfZbH010128@laptop11.inf.utfsm.cl> References: <200506282141.j5SLfZbH010128@laptop11.inf.utfsm.cl> Content-Type: text/plain Organization: EGBOK Consultants Date: Tue, 28 Jun 2005 18:08:48 -0700 Message-Id: <1120007328.29900.67.camel@Quirk.egbok.com> Mime-Version: 1.0 X-Mailer: Evolution 2.0.2 (2.0.2-16) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org I originally sent this as a private reply to Horst, not having seen it show up on the list. I can't resist tinkering, so this version is slightly improved from the one I sent earlier. Sorry for the duplicate, Horst. Thanks so much for your reply! If I needed the device to work for some practical purpose, I would agree with your suggestion, and call the problem solved with a userland driver. However, I'm interested in writing a proper driver mainly for the fun and education of the effort. There is another hobbyist interest that attracts me about the project. That will take a little explanation, if you will indulge me. The HP-41C won over a generation of engineers. It was a computing system, rather than a mere programmable calculator. At about the same time as the MITS, Altair and Apple 1 hobbyist microcomputers, HP came out with this expandable machine. They also designed, and later released the "dog-slow" HP-IL bit serial master/slave network. The fanatical following of HP-41 enthiusiasts peaked in the US in the mid-to-late 1980s. Before then, they had built a culture of sharing that was not unlike what emerged as the Berkeley branch of the "Open Source Movement." The legacy of all this is a mountain of technical literature and software. Hewlett Packard added greatly to the hoard by cutting loose of most of the internal documentation on the HP-41C and its peripherals under a "don't bother us" license. Nowadays, there is still a community of engineers and similar folks who like to play with HP-41Cs. These folks also have about 100 other HP calculator models to play with, but the 41 seems to hang in there near the top of people's lists. The culture partakes of the earlier sharing culture that the original fans built. However, most of today's participants are DOS or Windows users. For example, there are half a dozen HP-41C emulators that run on PCs. All but one run on DOS/Windows only. One of these is EMU41, by J. F. Garnier. This is a DOS application that emulates the 41C at the microcode level. J. F. has also written code to emulate the HP-IL loop, so his virtual calculator can have virtual printers and disks attached to it. Another one of the old timers of the HP-41 world, Cristoph Klug, has kept up correspondence with M. Garnier. He decided to start raiding old HP-IL hardware for chips so he could produce a new supply of the old HP-IL ISA card. This is the card I'm interested in writing a driver for. Cristoph suggested to J. F. that he modify EMU41 to allow it to talk to the real HP-IL board. J. F. did this, and the result is a hardware/software combination that lets virtual and real devices communicate over the HP-IL loop. It's pretty cool. But J. F. and Cristoph are both old school. Neither of them have expressed much interest in Linux. (One thing I hope to do is to tempt them into paying more attention to Linux.) I entered the picture a mere six weeks ago. I had been looking for a software calculator to port to pdaXrom, a Linux OS for the Sharp Zaurus clamshell PDA models. I ran across Nonpareil, the one and only HP-41C emulator for Linux that I mentioned above. I successfully ported it in an afternoon. (This is testament to the hard work of the pdaXrom crew and to that of Eric Smith, the author of Nonpareil.) That got me thinking about my old, long-lost HP-41CV. I ended up buying one on eBay and the rest, as they say, is history. I was hooked by the idea of wedding the HP-41C, which is the machine on which I first learned to program, to Linux, which has been my favorite OS since 1992, and is currently what gives me the resources to buy old calculator gear. The idea of bringing together the earliest computer technology I had contact with and the latest cutting edge was irresistible to me. So I've been in discussions with Eric Smith about emulating HP-IL for Nonpareil. Eric is an obscure CPU microcode wizard. (Obscure CPU, not obscure wizard. 8) Nonpareil doesn't merely emulate the HP-41C, it also emulates every HP calculator leading up to the 41C with varying degrees of success. Eric is a guy who could produce working emulations of disks and printers, if I could talk him into it. And given a reasonable device interface, he could talk to real hardware too. So that's my intention: to provide Eric with a reasonable driver for the "HP-41C peripheral virtualization project," and to learn about 2.4 and 2.6 character mode drivers while I'm at it. Longer term, I want to design and implement a USB interface to the HP-IL IC. That way I could talk to my HP-41C from my Zaurus running pdaXrom, and then I wouldn't need Nonpareil 8). (Although I'd still probably want access to the virtual HP-IL driven coke machine Eric will undoubtedly write.) Thanks again for your note! Best regards, Howard On Tue, 2005-06-28 at 17:41 -0400, Horst von Brand wrote: > Howard Owen wrote: > > I've embarked on a project to write device drivers for an obscure and > > rare ISA card. It's a modern version of the HP 82973 HP-IL interface > > produced by Cristoph Klug. HP-IL was a bit-serial, dog-slow version of > > HP-IB (IEEE-488) that was designed to work with the HP-41C family of > > calculators, and later with the HP-71 and HP-85. The 41C calculators are > > my hobby interest. I'd like to introduce myself, and ask for pointers > > for a newbie device driver author. > > As you say later you have stuff working in userland under DOSEMU (and the > "dog slow" part), I'd suggest a userspace driver. It is probably easier to > work with, and has the advantage that you can run it under the bog-standard > $DISTRO kernel with some care, no patching/reconfiguring/rebuilding to be > done. > > [No, I'm just an old hand here; no expert of any sort. Good luck!] -- Howard Owen hbo@egbok.com "Even if you are on the right EGBOK Consultants Linux Architect track, you'll get run over if you fwd:50279 pstn:+1-650-218-2216 just sit there." - Will Rogers