The Apple-1 Software Library ^Beta

Also referred to as Integer BASIC. Sold by Apple Computer on cassette tape for $5, order code A1T001X.

History

At the time, BASIC was a very popular language that enabled people to do more stuff with their mini- and microcomputers more easily. In order for the Apple-1 to succeed it needed a BASIC.

Apple BASIC was written by Steve Wozniak himself and later on improved further by other people. It did not support floating point arithmetic, so no decimals could be used. It was open source and was shared amoung fellow hobbyists.

Instructions

The Preliminary Apple BASIC Users Manual explains how BASIC is loaded from cassette tape:

Hit the CLEAR SCREEN button which will clear the screen and display only the cursor (a flashing @ sign) in the upper left corner of the screen.

Hit the RESET button which will cause the computer to print a backslash (\) and move the cursor down a line.

Place the BASIC cassette into the recorder, rewinding it if necessary.

1. Type C100R RETURN
2. Type E000.EFFFR (don't hit RETURN yet!)
3. Start the tape
4. Hit RETURN
5. When BASIC is loaded (about 30 seconds) the computer will print a backslash (\).

To enter BASIC type E000R RETURN. The computer will print a few characters, then, on the next line, print the prompt character >. This prompt character (>) is used throughout BASIC to signify that the BASIC is ready for additional commands or statements.

To exit BASIC hit the RESET button. This will return control to the monitor. To re-enter BASIC from the monitor without losing the previous program, enter BASIC at E2B3 RETURN, instead of EOOO RETURN. This is extremely useful when you have unintentionally hit the RESET button while in BASIC. Normally, you should enter BASIC at E000 RETURN, which clears any previous programs.

The various BASIC statements and control structures are explained further by the manual.

Versions

Several versions are known to exist. Wendell Sander did some research into this:

There were many versions of Apple 1 Basic provided by Apple in the early days. There was just Woz and SJ and Woz was writing Basic while the computers were being sold. When someone got a copy from SJ it was just the last stable version from Woz.

I bought my Apple 1 at a Byte Shop in mid 1976 and I got 4 different versions of Basic over the next 6 months or so. I labeled them version A through D. Version A did not even have an INPUT statement so about all you could do is print HELLO WORLD. Version B added the INPUT statement, Version C added Arrays and Version D added PEEK and POKE. I have copies of C and D but have not been able to find any earlier. The Huston brothers got a copy of Apple 1 Basic in late 1977 or early 1978 when they were employees at Apple that includes a checksum program and I presume that was the last version. By late 1976 and early 1977 Woz was focused on the Apple II.

Based on the above, together with a blog article and another topic, the following comparison can be made;

Maybe Woz has the early versions still lying around, who knows?

Example program

The following program can be entered while running BASIC. It displays the fibonacci numbers and can be started with the RUN command. Use LIST to check if the program is entered correctly.

05 REM Fibonacci numbers 
10 LET M = 5000
20 LET X = 1 : LET Y = 1
30 IF (X>M) THEN GOTO 100
40 PRINT X
50 X = X + Y
60 IF (Y>M) THEN GOTO 100
70 PRINT Y
80 Y = X + Y
90 GOTO 30
100 END

References

• Preliminary Apple BASIC Users Manual as provided by Apple Computer.
• Personal website by Wendel Sander explaining the differences between versions of Apple BASIC.
• Byte code comparison of the versions by Wendel Sander.
• Pagetable blog article by Michael Steil about the reconstruction of Apple 1 BASIC from a cassette tape. Referred to as the Pagetable BASIC version.
• History of an early BASIC patch, a topic by Colin Howell on Applefritter.
• Tips for loading BASIC by Larry Nelson on Applefritter.