Software for the Old Machines

They contained software for the HP-41, HP-75 and HP-71 systems. The disks are available today as "LIF" images, which are raw bit copies of the old disks, including formatting. These images are available at ftp.math.jyu.fi and at The MoHPC FTP site. Both sites have software for writing the images to floppies on old PCs running DOS. The JYU site has them one level up from the given URL, and the museum in the hpil subdirectory. The museum also has the files each disk contains broken out individually in the swap directory under hpil. Be that as it may, it's hard to take advantage of these disks on real machines today. That's due to two factors. First, these LIF images are for single sided, double density disks, which modern PCs have trouble handling. Due to the lack of support for single-sided media in modern BIOS, I know of no program that will write to real single sided media on any PC I own. (My systems range from a Pentium/75 to an Athlon 64, with lots of steps inbetween.) Fortunately, lots of utilities will read such disks. Also fortunately, a couple of utilities will write a single sided image to double sided media. Still, dealing with these images on real media can be a pain.

The second problem is that not overall index exists for the contents of the swap disks. I'm trying to remedy that with a project I call Swapdex That link is to a Wiki for the project, which you are most welcome to contribute to, if you wish.

To get around the disk access problems, you can use emulators for the HP-41 and HP-71 (but not for the HP-75). The best ones to use for accessing HP-IL are those by JF Garnier. They run under DOS, but you can use DOSEMU and FreeDOS to make them work under Linux. If there is no requirement to access real hardware, the LIF images alone will give you hours of fun, and opportunities to contribute to swapdex, of course. 8)

If you do want to access real hardware, you have a couple of choices. You can use the emulators, or Tony Duell's LIF utilities for Linux to extract individual files. You can then use the HP 82164 HP-IL to RS-232C interface to transfer the software to the calculator or handheld computer. Tony has a nice article about this at the MpHPC site. Second, you can do what I did, and grab one of Christoph Klug's HP-IL/ISA cards, or an original HP card. You'll need an older Intel machine for the ISA slots, but you've already proven you like old computer hardware, of you have read this far. 8)

I never touched an HP-71B back then, let alone programmed one, but there were, nonetheless, strong points of reference between the machines I did use and this cool little handheld BASIC computer. Even though the BASIC on the 71 is much better than Applesoft, to give an example of a language I used an awful lot, the similarities were stronger than the improvements HP's BASIC offered. In a nutshell, BASIC sucks. The line numbers clutter the code visually, and nine times out of ten serve no other purpose than that. Compounding this, the interpreter in both machines renders all keywords and variable names in upper case only, regardless of how you type them in. Then there's the generous provision of two whole characters for variable names themselves. And the second character has to be a number! Yecch! I knew all of this at one time, and blissfully forgot about it as I went on to more capable languages, with their own set of endearing quirks and foibles.

So why do I feel so good about having written this stupid little Yahtzee clone in BASIC? I guess it's the pride of having overcome the visual clutter, the enforced spaghetti, the unhelpful variable names, the slow speed and tiny memory to produce something that actually works. This is a game that I actually play every day. (But I'm easily amused.)

The 9816 is a machine I programmed professionally at my first real programming job. Far more detail about this than you may be interested in is in the README file. That file also contains instructions for playing the game.

The Pascal is HP Pascal version 2.1. I make the disks available here in two formats. The first is "teledisk" format. This is a DOS program that will read and write double sided, double density disks. It also will read single sided disks. It won't write to single sided media on my P75, but it will write single sided images to double sided media, or even to standard HD media if the second open tab is covered with tape to simulate DS/DD. These images are single sided, but you can write them to double sided disks by telling teledisk to only use side "0".

The second format presented here is a straight sector-by-sector image copy. I obtained thes using a version of Tony Duell's lifimage, which is part of his LIF utilities distribution for Linux. I hacked his code so the program would only read from cylinders 0 to 69, head 0 and sectors 0 to 15. This allowed the image copy to complete without error. Here are links to the teledisk program, a ZIP file containing all the teledisk images images, and the individual images as well. Following this is a tar file with all the lifimage images, and then each of those files individually. These are compressed using gzip.