Show Dec 22, 2010

Dec - 08 2010 | By

Play the Atari "Battle Zone" arcade tank game from 1980 Here!!

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Ed Rotberg was the guest today. He was the programmer & designer of the Atari game called Battle Zone, a vector graphics, tank commander, shoot-em-up style game from about 30 year ago.
Paul asked how much memory & speed were required for the game at that time.

Ed said those early video games didn't have hard drives but used ROM to store the program. RAM was 256 to 512 bytes and about 4K of ROM.

Battle Zone was programmed in assembly language. At that time, each computer instruction was 1 byte long <8 bits> so there was a max of 256 instructions available.
– It took about 9 or 10 months to finish programming the game but it involved long hours.
– The CRT was special. It didn't do raster scan but vector graphics instead.
– The circuitry & peripheral capabilities around the microprocessor were uniquely designed for each new game that came out.
– Battle Zone was not the first vector graphics game by Atari, but it was the first fully 3D arcade game.
– There was no hidden line removal so the tanks, and such, were transparent.
Collision detection required a lot of computing power, so only one projectile at a time was allowed to be fired.
– The positions of the tanks were actually done in 2D. The missiles and exploding debris were the only things that could change vertical positions.
– The microprocessor used was the 6502 by Mostek. That was the same chip used in the Commodore 64 & the Apple 2 computers.

There is a Java-based emulator of Battle Zone, See the above link. Ed said the emulation is very accurate.
– The emulator uses the actual ROM image from the game.
– All of the hardware is emulated.

Paul mentioned that the movie Tron Legacy has just come out. The original Tron movie was by Disney and came out in 1982 or 1983.

Atari would not let the programmers put their names in the credits for fear that some other company would try to hire them. Eventually they were allowed to use their initials in the default values of the highest score table.

After Battle Zone, Ed co-programmed for one project and directed another project, neither of which were finished before he left Atari to form his own company.
– The first project was the original Star Wars game.
– The other was Dragon Riders of <something I couldn't make out>. It never made it to production.
– Star Wars was a vector graphic game.
– Dragon Riders, eventually called Fire Beast, was a raster graphics game.
– Raster games, at the time required too much horsepower to run in 3D.
– The 6502 chip ran at 1 megahertz, 1,000 times slower than a 1 gigahertz processor.
– The chipmaker AMD isn't making even 32bit processors anymore, only 64bit. And most distributions of modern operating systems are 64bit.

Ed said that few students of programming actually learn assembly programming these days. They are not likely to use assembly, though it does provide insight into how things work in the computer. He said it has helped in writing more efficient code. It has also helped to take advantage of the limited hardware they had back then. Now days, game designers don't need to know the technical aspects of their creations because the tools (programs) they use are so sophisticated. The designers can then concentrate on the creative aspects. But, eventually, a programmer has to incorporate all the design elements into the completed game.

The 6502 had 4K transistors, compared to the current processors that have hundreds of thousands. The chip was priced well below its competitors like the Intel 8080 & the Z80. Ed said the 6502 was more efficient than the others even though it too had a 8bit buss and a 16bit address space.

At the time Ed was writing Battle Zone, the US military approached Atari to write a training program. They wanted a simulator for the Bradley fighting vehicle. Ed, being a pacifist, was not thrilled and Atari was not amenable to the extra documentation that the military required. But he did work on the project and had to put in long hours to meet the deadline.

Paul asked Ed what he thought about current games being so realistic. Ed said he's happy with the trend but he's not pleased with all of the violence. He said many parents don't want to monitor their kids and expect the government to issue standards. He's mostly avoided working on violent games.

Paul asked if Ed had worked with force feedback handsets.
– Yes, he's worked for Silicon Entertainment on a NASCAR simulator game console. It provided physical feedback as if the vehicle was shaking or rounding a corner, etc. It cost the player about $7 for the experience.

According to Ed, the better arcade games had a lifespan of about 1 year. It depended on how much they were earning.

There were a couple of versions of Battle Zone. The original had a periscope feature, but it limited how many people could watch, and that limited its earning potential.

Paul wondered how the games were market tested.
– Ed said they used focus groups or they would just monitor how much it actually earned.
– Later on, they made the consoles collect data on the usage. Eventually, they put modems in them so the data could be sent back to the company.
– They had to make sure people didn't play too long or too short for each quarter spent. Too long and the company wouldn't earn as much money. Too short and the player would stop playing out of frustration.
– Some games were made with reprogrammable ROMS so the gaming experience could be changed.

The game Lunar Lander was mentioned. It was another game that Ed worked on.

Ed talked about there being collectors of arcade consoles and conventions featuring the old games. He said about 50,000 Battle Zone consoles were produced worldwide. Atari sold them to distributors but not to the end operators. The distributors were the same ones who handled pinball machines & jukeboxes.

Ed appeared in the credits of the original Tron movie for his sound effects work.

The sounds in Battle Zone were generated from the ROM. But music from the 1812 Overture did use a sound chip. It was the first game to use the sound chip from the Atari 800 computer.

John called to reminisce about playing Battle Zone in junior high. He also mentioned some controversy about the library lending violent games and wondered what other options are available for teenagers.
– Paul mentioned the video game called Mist that was non-violent.
– Glenn suggested getting kids to read books or get outdoors.
– Try to achieve a balance of entertainment options.

There was some talk about rating systems. First applied to movies and music and then to video games, the rating systems can get politicized. People will take positions for political reasons and lose sight of what's best for kids. Ed thinks censorship by the government sets a bad precedent and that parents are in the best position to oversee their children.

Some games have had hidden content inserted by the programmers. The content sometimes violates the rating of the game and causes controversy when discovered at a later time. There is a website dedicated to these easter eggs at

Paul said there are sometimes easter egg facilities in CDs — a hidden track called track 0. You put the CD into the player and it starts playing at track 1, but if you hit the button to play the previous track, it will, on some players, play track 0 — the hidden content.

Glenn mentioned that he couldn't find the original Tron movie on DVD. Ed said it should be available. Apparently, it was on Netflix, specifically, where Glenn couldn't find it

Paul said the audio of this show will be "stored up" on

Last updated: 9:51 PM 12/22/2010 

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