BioTerror! An Original Commodore PET 2001 Game by Jason Grow

BioTerror! is a turn-based strategy simulation in which you manage resource units to quarantine cities, research a cure, and eradicate infections. The game was written in 2011 for a 1977 Commodore PET 2001-8. This computer only had 8kb of RAM and 40 columns on a colorless screen.
Learn about the Commodore PET 2001.

If this game sounds interesting to you:

Visit http://www.viceteam.org/
Download the VICE Emulator and run xpet.exe.
Download bioterror!.d64
Attach it as a drive 8 disk image.
Type LOAD "*",8
After the program loads, type RUN

v1.0 commands include:

QUARANTINE [CITY NAME OR #] - quarantines cost Resource Units every day to maintain. You can quarantine any city, whether infected or not. If the city is infected, a quarantining will minimize the risk of outbreak. If the city is uninfected, the quarantine will minimize the risk of becoming infected. Manage your quarantines carefully though. As time goes on, the quarantines become less and less effective. The cost of a quarantine is dependent on a city's population count.
LIFT QUARANTINE FROM [CITY NAME OR #] - removing a quarantine can free up resource units for other activities, such as upgrading your research level. Removing the quarantine for a day will also reset the effectiveness rating back to 100%, but this is an expensive strategy.
RESEARCH [CURE CODE] - Conducting research is the first step to eradicating the infection. The simulation selects a random series of letters and numbers (no duplicates). The player guesses at these random characters and the simulation flags the code when you've found a character.
UPGRADE RESEARCH - The player can only conduct research 1 time per day. Upgrading your research will give you additional daily research attempts, and will also generate more Resource Units each day.
CURE [CITY NAME OR #] - Once you've found the cure, you must share it with each city. The cost for curing a city is dependent upon the remaining population. High populations cost more to cure.
NEW DAY - You have to move to a new day in order to conduct more research. This command initiates your next turn.
DAY [NUMBER] - If you are lazy or you just want to watch the numbers, you can jump straight to a particular day. You can hit any key to halt the simulation on a given day as it plays through.
REPORT - this page shows the user the city numbers, starting and current population counts, and percent of population infected.
MAP - shows the strategic map.

The idea for BioTerror! began 25 years ago when I was making key-graphic (aka PETSCII) screens on my C-64. After watching the movie WarGames, I wanted to produce my own version of Global Thermonuclear War. I started with the map of the Unites States. I did not have the artistic vision at the time to create a decent map, and since I was only 15, I got bored with the idea and let it rest...for 25 years.

Fast forward to the middle ages, and I had a hunger for 8-bit nostalgia. I attended the Classic Computer and Arcade Gaming Show in Cleveland back in 2010 and from there I energized my Commodore collection. I also watched scores of YouTube videos which introduced me to Phreakindee, Ben Heck, Jeri Ellsworth, KMoser, and many others. Phreakindee and Kmoser were publishing reviews of old stuff that I had never seen before, and that was as good as new to me. Jeri and Ben inspired me the most because they were doing new things with old computers. And they weren't just doing new things, they were doing great things.

I became a daily Craigslist stalker for Commodore machines, and after a year of constant search I found what was, for me, the holy grail of Commodore computing, the PET 2001. I brought it home, meticulously cleaned every nook, cranny, and contact of the machine, and began keybashing on the chiclets. My fingers were aglow with tingling sensations that are only reproduced by 2 things: good sex and vintage keyboards. I was in a state nerd-vana.

I started building key-graphic screens on the PET just to give me something fun to do. The failed C-64 WarGames map from my youth was haunting me in my sleep, so I stayed up late one night and played around with the keyboard until I got the map just right. I took a picture as a keepsake because the tape drive was unreliable. I started saving the map to tape and watched with horror and grim fascination as the screen slowly faded to black. The PET was dead.

My beloved PET, with the map
in progress, shortly before death. Notice the wire coming out of the cassette drive?

My software skills far outweigh my hardware skills, and I could not repair my PET without the help of some real hard-core 8-bit Commodore folks. There weren't any of those people within driving distance of my house, so I decided to resume my fun on the WinVice PET emulator available from viceteam.org. I created a PET keyboard by making a sticker sheet of an original PET keyboard. I cut these out and adhered them to a standard Dell PS/2 keyboard and resumed my work on my desktop running Windows XP. Since I saved the map to tape, I was able to read the analog cassette through my soundcard and convert it to a d64 disk image for use with WinVice. Here's the wav file which sounds like a fax machine. The only question remained...what can I do with the map?

The PS/2 PET keyboard I made to continue my work on a PC. Also shown is the cassette adapter that I used to record a wav file of the map through my PC sound card.

The game concept evolved over the course of a few sleepless nights and countless frosty pints. It is difficult to say how everything came together. I just kept coding various ideas until I had a playable thing. I wanted the player to be engaged by issuing orders in plain English. I wanted a strategic map, informational reports, resource management, and constant threats of danger. I wanted more than I could cram into 8kb though, and some of my best ideas were axed to keep the game small enough to run on the original 8kb PET. I cut out the animated intro screen, which was later turned into a loader page. I removed the rioting that reduced quarantine effectiveness. The most detailed aspect of the game was centered around dispatching research teams to conduct research....also ripped out of the game to save memory. The most disappointing piece to get removed was "Code Mutations". Once you found the the cure code, it was possible for the code to mutate, forcing the player to research another character. This also had the nasty byproduct of re-infecting cities.

A later (but not final) version of the map. I decided to remove some of the city connections to save memory.

The most challenging aspect of the entire project was dealing with the limited 8kb of RAM. I refactored my code more times than I could count. I found myself shortening messages just to gain 3 or 4 bytes of memory. I removed every unnecessary space, line of code, variable and REMark that I could find. The final game leaves only about 500 bytes of memory to operate. I wouldn't be surprised if a player ran out of memory if the game ran long. I was fortunate to have a very experienced gamer spend a couple hours play-testing.

Code in the process of being refactored.

Despite removing those aspects of the game, I feel that my original concept remained intact. The final product was both fun and time consuming. The game has given me a great platform for introduction to other Commodore enthusiasts, and for me, that has been the real payback for my efforts.

Thanks for your interest in my game!

Jason Grow

Comments or bug reports?
jason.grow@greatnorthweb.com

My son and play-tester, Logan, at the 2011 CCAG Show in Cleveland. We had many computers on display, but since the PET was dead, I had to run a video of BioTerror! on my Galaxy Tab.