Restoring Woz's Original Apple BASIC

You might not realize how much early microcomputer software has been lost over the years. Steve Wozniak's Apple BASIC is a case in point. Only a few original copies of the tape still exist, and there were no perfect binary dumps of the 4096 byte file until Michael Steil recently decided to try his hand at reading a 2002 mp3 audio recording [mp3] of the original 30 second cassette file. Using the Audacity audio editor, he was able to successfully reconstruct the signal as a series of square waves that could be decoded algorithmically.

The critical question, of course, is how much other classic software is in desperate need of archiving and restoration to ward off being lost forever. Decades-old tapes and floppy disks are prone to deoxidization and drop-outs that render them useless. The truly sad thing is that many collectors may not realize that the rare magnetic media sitting on shelves in the basement is decaying at an alarming rate.

Apple BASIC was offerered cassette tape for the Apple I. Users needed 8 KB RAM and the Apple I Cassette Interface to run it. It lived into the 1980s - renamed Integer BASIC - stored in ROM on the Apple II. Scientifically-inclined users quickly soon demanded floating-point math, and Apple turned to Microsoft to create Applesoft BASIC, obtained under an eight year license for a mere $31,000.

Steve Wozniak once described his BASIC interpreter as the most challenging part of designing the Apple I and Apple II computers. It was coded directly in machine language, because he couldn't afford a compiler. This also helped Woz to write extremely tight code.

The original Apple BASIC syntax charts included floating-point math functions, but Woz stripped them out in an effort to save time while racing to complete the first BASIC for the 6502 microprocessor (my quick look at the binary dump reveals there wasn't sufficient space to cram floating point functions into a mere 4K, either).

Woz reveals, "I'd never studied compiler/interpreter writing and had only practiced my ideas on paper before. I'd read some good books on the subject. I'd never programmed in BASIC before the Apple I. I just sniffed the air and decided that the games that would drive personal computers were written in BASIC. I picked a manual at Hewlett Packard and used their variant of BASIC as my model." It turned out to be the right decision, and Apple BASIC -- which Woz aptly refers to as "Game BASIC" -- gained a reputation for speed.

Let's hope the successful restoration of Apple BASIC encourages other vintage microcomputer enthusiasts to make copies of their old software before its too late.

Reconstructing Apple I BASIC from a Cassette Tape [via TUAW]
Scan of the original 16 page Apple 1 Basic manual