Screen Art: HP 9845C Demo

The HP 9845C Demo

The demo package for the HP 9845C is remarkable for several reasons. One aspect is that it is one of the most complex BASIC programs ever developed for the 9845 series. The demo required two full tapes as distribution media, and the main program alone consisted of more than 4,000 lines of BASIC code. The other, more important aspect lies in the fact, that HP's engineers not only demonstrated the outstanding capabilities of their 9845C system with high resolution graphics, fast vector engine and up to 4,913 colors, they also used the 9845C as platform for implementing many state-of-the-art concepts in computer graphics and human interaction, like 3D shading, ordered dithering, wireframe rendering, interactive light pen control or just using color for better visualization of complex data.

The demo had been primarily developed by Colin Cantwell, who also played a crucial role in the design of Star Wars' space ships such as Tie Fighter, Star Destroyer or X-Wing Fighter. Colin worked as a consultant for the team which created the 9845C color system and had been a visionary for computer graphics applications. He also supported the creation of the War Games movie by programming all the tactical NORAD screens of that movie with an HP 9845C (see the War Games Section for more information).

HP itself

HP itself

The examples which were chosen for the demo covered a large scale of applications the 9845C was intended for. In total there are six cathegories, each consisting of six demo applications, giving all together 36 different demo cases. Each demo case has its own controls, so for example different visualization parameters, data sets, object parameters or viewpoints can be selected. The whole demo application is completely menu-driven, with one main menu and six submenus. Navigation within those menus is possible with both light pen or soft key control. The cathegories are:

  1. Main menu (Color Graphics)
  2. Introducing Color
  3. Computing with Color
  4. Engineering Applications
  5. Scientific Applications
  6. Management Graphics
  7. Advanced Graphics

These sections range from basic information how to produce and to use color on a computer system, over general data visualization techniques and common engineering, scientific and business applications up to using 3D graphics for architects and a light pen controlled, color graphics computer game (Gravity).

Space Shuttle Demo

Famous Space Shuttle Demo

9845C Shuttle Demo

The Shuttle Demo on a Real HP 9845C

The space shuttle demo was created by Colin with a 9874A digitizer. If that looks familiar to you, it has been re-used as a standard demo in Autocad for many years.

9845C Demo

My Son Demonstrating the Gravity Game as Part of the 9845C Demo

The demo software was part of each HP 9845C distribution package as part number 09845-15240 and included two software tapes plus user manual. Although today there are in priciple still enough demo software tapes available, most suffer from data loss due to defects of the magnetic coating. Since there have been several versions produced, it was not possible for me to reconstruct one complete demo program from the tapes alone. Fortunately Jon from the hpmuseum found one complete set of demo files on one of his backup disks, so it was possible to run the full demo and to take example screenshots in order to get an idea of the capabilities of the 9845C.

Actually, it is not sure whether it is easier to find a complete set of demo software or a working 9845C system to run it.

If you like to see the demo in action, here is a record of a Polish science series from 1980 where the HP 9845C had been introduced. Of course, you need to know Polish to understand the dialogs, may be there is someone who likes to add subtitles...

Just click on the links to start playing from YouTube:

Sonda 1 Sonda 2 Sonda 3 YouTube
part 1 of 3
part 2 of 3
part 3 of 3

Sonda was a cult-classic Polish popular science program - the recorded episode entirely focused on the HP9845c computer (thanks to Michal for the hint).

You also can run the full demo on your own PC with the HP 9845C MAME based emulator (see the emulator project for instructions).


Below are 9845C produced screenshots taken from the demo on an HP 9845C system. Also have a look into the 9845C demo screen dump gallery to get an impression on the original binary graphics bitmaps produced by the 9845C demo.

Click to enlargeStart Screen Click to enlargeColor Graphics Menu Click to enlargeIntroducing Color Menu Click to enlargeClipper Ship Click to enlarge4913 Colors
Click to enlargeColor Cube Click to enlargeColor Cylinder Click to enlargeColor Shading Click to enlargeMixing Light Click to enlargeComputing Menu
Click to enlargeColored Line Click to enlargeCross Sections Click to enlargeOpaque Planes Click to enlarge3D-Surfaces Click to enlarge3D-Prisms
Click to enlargeColor Plots Click to enlargeEngineering Menu Click to enlargeSpace Shuttle-1 Click to enlargeSpace Shuttle-2 Click to enlargeSpace Shuttle-3
Click to enlarge3D-Rotation Click to enlargeField Strength-1 Click to enlargeField Strength-2 Click to enlargeField Strength-3 Click to enlargeStress Analysis
Click to enlargeIC-Wafer Yield-1 Click to enlargeIC-Wafer Yield-2 Click to enlargeFloor Plan Click to enlargeScientific Menu Click to enlargeHydrogen-1
Click to enlargeHydrogen-2 Click to enlargeHydrogen-3 Click to enlargeAcid Rain Click to enlargeXRay-Astronomy-1 Click to enlargeXRay-Astronomy-2
Click to enlargeJupiter-1 Click to enlargeJupiter-2 Click to enlargeJupiter-3 Click to enlargeJupiter-4 Click to enlargeIce-Movement
Click to enlargePlanets Click to enlargeManagement Graphics Menu Click to enlarge3D-Bar Chart Click to enlargePrism Map Click to enlargeArea-Color
Click to enlargeBar-Chart Click to enlargePie Chart Click to enlargeAdvanced Graphics Menu Click to enlargeArchitecture-1 Click to enlargeArchitecture-2
Click to enlargeArchitecture-3 Click to enlargeArchitecture-4 Click to enlargeCIE-Diagram Click to enlargeComputer Mapping Click to enlarge3D-Wireframe-1
Click to enlarge3D-Wireframe-2 Click to enlargeTopography Click to enlargeGravity Game


Click here for downloading files related with the HP 9845C demo software:

HP disk image with the complete demo software:
HP 9845C Demo Guide: 9845C-Demo-Guide_09845-15241-29pages_Sep80.pdf

Please note that the demo software requires a light pen installed. If no light pen is avaliable you will have to comment out the instructions which produce error messages.