Posts Tagged ‘HP 9845’

Tanks & Jets

Tank & Jet Games


We had two games involving tanks: “Tanks” (very clever, huh?) and “TankJet.” Tanks was a simple player-vs-player tank battle. TankJet, however, featured one or two players against the computer. (Or against each other, if you were a devious, back-stabbing bastard, huh Brad?) The jets were high-precision scale models of the new F-16s, as you can see.

In battle, you swooped in on a tank column and tried to blast them while they were shooting back. The tanks determined which jet was the greater threat and estimated your future position and fired an anti-aircraft shell at you. Working as a team, (“team”–you understand the term, Brad?), one would fly at the tank to draw fire while the other tried to destroy it.

If you were shot down, you could eject (unless you were too low, which was the best attack profile) and parachute to safety. However, the low-class tank commander might decide to shoot at you, anyway. Then it was up to your partner to defend and protect you. (Yes, “defend and protect,” not run away like a friggin’ coward!)

Not the most graphically or computationally spectacular game we wrote, but definitely one of the most fun!


Star Trek

Star Trek


What self-respecting NASA computer wouldn’t have a Star Trek game? This was mostly Brad’s creation. I provided invaluable design advice (“That sucks. Make it look better.”)

You played on a 100×100 “universe.” Long-range scans told you where Klingons and Romulans lurked. You would move into their “quadrant” and use short-range scan to find them, switch to “Bridge mode” (with viewscreen), and fire phasers or photon torpedoes until the enemy blew up. Romulan Birds-of-Prey were, well, easy prey. Klingon Battlecruisers, however, could give nearly as good as they got. And if you had to fight several at once . . . (“Captain’s log, supplemental: HOLY SHIT!!”)

During battle, you would take damage to whatever side of the ship was facing the enemy. Once your screens on that side were down, you started losing power to critical systems (computers, life support, navigation, engines, weapons). The game required fast thinking to switch to Damage Control mode, re-route power from less-critical systems to weapons (fight) or engines (flight), and continue battling, all the while shouting things like, “I’m doin’ all I ken! I canna change the laws o’ physics!”

Assuming you didn’t get killed, you could navigate (if you still had nav, computers, and engine power) to a Star Base, dock, and re-energize.

It wasn’t exactly The Original Series, but it beat the hell out of NextGen.


Lunar Lander Simulator

Lunar Lander Simulator


This was our most ambitious project. It started off as nothing but a squarish vehicle that dropped from the top of the screen to the bottom, much like the commercial Lunar Lander in the arcades of the time. You turned the engine on or off and tried not to hit too hard.

Eventually, we had the capability to descend from orbit, flying over a pseudo-randomly generated terrain. You controlled your horizontal velocity (which started at about 5500 fps when running in the “deorbit” mode) and vertical velocity by throttle and pitch. You controlled pitch by commanding a pitch rate or, if you were incredibly foolhardy brave, by turning on and off jets. An onboard guidance system could fly the entire profile for you, selecting a candidate landing site and taking you to it. Of course, that option was for wusses.

Along the way, you had to deal with numerous failures (how numerous and how bad depended on the skill level). You could have pitch jets fail (on or off), navigation biases or dispersions, fuel tank leaks or failures, computers failing, even a main engine failure. Fortunately, we had an abort mode that separated the top stage of the LM and took you out (assuming you were within the allowable pitch and pitch range).

The grid of lights are called DDDs (Digital Display Drivers), which are commonly used at NASA. The engine characteristics and mass properties of the LM are accurate.

We also had much simpler modes for beginners, which basically involved just throttling the engine up and down as you descended to the landing site.

These images are from the final version of the program. These are actual screen shots; I rewrote the entire program into C++ for the PC. Visually and functionally, however, it is virtually identical to the HP (even down to the monochrome green graphics).

NOTE: One earlier version had a different abort sequence: the pilot ejected from the LM, his/her chute opened–only to collapse, since there’s no air on the moon–and then he/she flapped his/her arms wildly until landing safely on the surface. At that point, the pilot would throw his/her arms up and grin wildly. I say “he/she” because the pilot could be of either gender. Don’t ask about THOSE graphics…. (Sadly, that version is lost to antiquity.)


HP 9845 Software

The Awesome HP 9845


I worked for NASA back in the early 1980s, where I had access to an HP 9845A/B desktop computer.

For its era, it was an awesome machine: 560 x 455 monochrome graphics, a fast, onboard interpreted BASIC, dual tape drives, a built-in thermal printer, plotter/digitizer tablet, and two external 8″ floppy disk drives, with an astonishing 256K each (the twin cabinets on the left of the picture below, each almost as big as the HP!). Our machine was decked out with a bunch of additional ROMs, boosting the machine’s capabilities even further. Of course, the $70,000 price tag might have been a bit excessive for the average consumer….

Without going into the gritty details, I will mention only that our boss allowed me and a friend to work on the machine after-hours, doing whatever we wanted. What we wanted, of course, was games. (The experience we gained showed up in our technical software, which is probably why he was so tolerant.) We just wished we could have talked into upgrading to the HP 9845C–with the color display!

Anyway, this web site is dedicated to the old HP. And to Brad.

Some of our games:

  • Lunar Lander Simulator: More simulator than game. It featured navigation failures/degradation, engine failures, fuel leaks/loss, computer malfunctions, etc. It pretty much required two people (pilot and systems). Surviving required both analytical thinking and quick reactions. I rewrote the game a few years ago, using exact copies of the original graphics, into C++ for the PC. (More…)
  • Baseball: The American classic! Customizable teams and players. One person selected pitch and controlled the defense; the other guessed which pitch (which varied how far you hit the ball) and controlled the baserunners. Lifetime stats were kept for each player. This game even featured crowd movement in the stands!
  • One-on-One: I loved this game. Both people create players according to the skills they choose and play against each other. Included real (and random) officiating–just like the real thing.
  • Star Trek: An exact recreation of the USS Enterprise and her systems. Okay, maybe not: but you did have to control navigation, life support, sensors, and weapons, all while under attack from pesky Romulans and Klingons.(More…)
  • Sub Hunt: The was the precursor to Search & Destroy. Find and sink the sub before he does the same to your fleet (and you!).
  • Jets & Tanks: Two games here: tank vs. tank or F-16 vs. tank. (More…)
  • Auto Racing: Grand Prix or Drag Race. More often than not, Grand Prix became Demolition Derby.
  • Cards: Solitaire or Blackjack–name your game.
  • Others: We had numerous other games in various stages of completion, before our career paths went in different directions: shooting gallery (pictured), where you shot at vehicles from every other game (including Klingon battlecruisers!), Mastermind, and probably others I’m forgetting.

Here’s to you, Brad.

Fellow computer genius