Yesterday I have written a blog entry with a small program to calculate date and time from a given Unix time stamp.
Like my HP41 I have used an HP48 for a long time (I am using an HP50G until today). There are several emulators for HP48 calculators (Android, iOS and so on). I am running such an emulator on my Android phone. So I have written the same program for the HP48.
If you like it, I am happy. It’s not a program to solve the problems of the world but it’s still useful for a simple job.


Simply enter the Unix timestamp (number of seconds) and run the program. The resulting date and time is shown in a message box.

More than 30 years ago I have used my HP41 to do the day work. Today there are several emulators for this very useful machine. So I have installed an emulator on nearly every device that I own. A stupid calculation that must often be done is to get the date and time based on a given Unix time. Unix time is given in seconds since 1.1.1970.
The calculation is easy done with a small HP41 program. If a CCD module or CCD OSX is installed (and a time module or the emulation of a HP41CX) only some lines of code are needed.
Here it is, a printout of a very simple program, that makes the job. Enter the Unix timestamp and run the program to get the real date and time.


Today we are working on programs with million lines of code. Even simple programs often contain several thousand lines of code. Writing such a small program within minutes that makes a simple job without any gimmicks is sometimes more fun than creating big software systems. Last time I have written a program for my original HP41 is more than 25 years ago. It’s like riding a bike, learned once, never forgotten.

I am working with computers since the late seventies. My first own computer was a HP86b from Hewlett Packard. I have needed a long time to collect all the money to purchase such a fully featured HP-System. For the HP86 I have written several commercial programs. A word processing system that was sold very often, a statistical system (sold sometimes), several big programs to drive testing units and several binaries. Writing binaries for the HP-Series 80 computers was a pleasure because the build in BASIC language could be expanded with new BASIC words. To do so, for every new BASIC word a definition must be given, sometimes a parser must be written and a at least the functional code must be written. If every thing was done well, the BASIC language was extended with a completely new functionality. I remember, sometimes a was a real hack to find the system internals needed to write advanced language extensions. All the code was written in HP Series 80 assembler.
One of my best language extensions was very usefull for nearly every user. I have expanded the system language by a great amount of essential commands. Because the language binary was very usefull I have translated the binary into ROM-code. Using a ROM-drawer a customer was able to install my custom ROM into a HP series 80 computer, expanding the system language without a need to load any additional binaries. I have given the name SYSEXT to this system ROM. And the word SYSEXT itself becomes a system language extension command. If someone enters SYSEXT into a computer equipped with my ROM, a copyright was shown on the screen.

Now it’s nearly 30 years later and  I have given the code for the SYSEXT ROM to public some years ago. Now an android emulator for the series 80 systems was build by Olivier de Smet. I have seen that the SYSEXT ROM was one of the preinstalled ROMs in the emulator. I have downloaded the emulator into my Galaxy S4, plugged in the ROM (not physically, activating it, switching it on within the emulator) and the language extensions are still present. So I have entered the command SYSEXT (the language extension command that simply shows a copyright) into the emulator. As expected, the emulator shows “(c) Andre Koppel Software 30.87″, a message from the past.

Brand new technology (Android, Galaxy S4) makes it possible to emulate very old systems showing the details and persons who have worked decades in the past with computers. This way I become part of the computer history. If someone likes to try the HP Series 80 computers, download the “go87″ App from GooglePlay. The manuals of the system and several details can be found on several web sites.

By the way, during the last 20 years I have written an emulator for the HP-Series-80 BASIC because it was a powerfull language, easy to learn. The BASIC language has become part of the ERP-System INVEP sold by my company. Sometimes a user writes own addons for our system using this language not knowing the history behind…

Here is a scan of the original promotional poster for my ROM (from 1984):


Die Firma Koppel Software erstellt seit 30 Jahren Software für Messtechnik, Anlagensteuerung und Automatisierung. Seit einigen Jahren sind Datenanalysen und Visualisierungen im Technisch-Wissenschaftlichenn Bereich hinzugekommen. In diesem Blog wollen wir uns zu verschiedenen Themen äußern und von Zeit zu Zeit auch Code für die Allgemeinheit besteuern.

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