A book by two professors of media studies examines the challenges of designing games on the Atari 2600, and posits that the infamous port of Pac-Man wasn't a half-assed effort after all.
Racing the Beam sets up the Atari Video Computer System (later 2600) as a console that profoundly shaped game design because its limitations forced programmers to come up with new efficiencies and tricks to deliver more complex games. The book also points out that it was an unusually long-lived platform - going into 1992 - despite its lightweight computing power.
The VCS' big setback, according to the book, is that the console had a tiny 128 bytes (yes bytes) of RAM, which could not accommodate a frame buffer - in other words the portion of RAM that stores the image data for each successive screen displayed by the game. So VCS programmers had to generate graphics purely in real time. For those who complain about how difficult it is to program for the PlayStation 3, this is the equivalent of "In my day, I walked six miles to school in the snow, uphill both ways."
By "racing the beam," programmers came up with a few tricks. The information space inside three blank spots that the electron gun didn't have to render was rededicated to things like joystick inputs, scoring and other processes. In some cases they shrank the playing screen more to give themselves more programming space. Pitfall!, one of the deepest games of its generation, made use of this.
Further, the VCS could only display two sprites on the screen at any given moment. How they compensated for that is a technical challenge that I can't intelligently describe. But suffice to say, in Pac-Man - a disappointing port partially blamed for the early 1980s video game crash - every time you ate a dot, the game redrew the screen. This manic redrawing accounted for the ghosts' flicker, which, of course, was justified because THEY GHOSTS after all.
The book's authors, Nick Monfort and Ian Bogost, say that arcade ports to the 2600 lay the foundation for future practices in bringing arcade games home. Says Bogost:
"The porting of arcade games to home systems was first really worked through on the VCS. It was because of this VCS development that developers were able to figure out what to try to carry over and what to leave behind, and how to adapt the arcade experience for more limited consoles that would be played at home."
The authors say Racing the Beam is the first in a series of "platform studies" that will probe how gaming platforms affect how games are created.
Racing the Beam: How Atari 2600's Crazy Hardware Changed Game Design [Wired]