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Altair BASIC programming

Bill Gates and Paul Allen wrote Altair BASIC. It was Microsoft's first product. At the time, Altair BASIC was a huge step forward as it allowed people to write programs using a high-level programming language. For more information about Altair BASIC, see the Altair BASIC reference manual.

By default Altair emulator boots CP/M. CP/M is more flexible and you can save files. That said, it's fun to fire up the original Altair BASIC, just keep in mind that you can't save Altair BASIC applications.

Boot Altair BASIC​

To load Altair BASIC, follow these instructions.

  1. From the web terminal, select Ctrl+M to enter the CPU monitor.

  2. Type basic, followed by Enter to boot Altair BASIC.

  3. You will be prompted for the following information:

    • MEMORY SIZE?: Select the Enter key to accept the default.
    • TERMINAL WIDTH?: Select the Enter key to accept the default.
    • WANT SIN-COS-TAN-ATN?: Enter Y or N.

    Altair BASIC responds with the amount of memory and version information.

Write and run an Altair BASIC app​

  1. From the web terminal, enter the following code to create an Altair BASIC application:

    10 for i = 1 to 1000
    20 print i
    30 next i

  2. Run the program by entering the following command:

    run

    Your program counts to 1,000.

Learn useful commands​

As you work with Altair BASIC, you'll likely use these commands often:

  • loadx : Loads a sample application into MBASIC memory
  • list : Lists application code
  • run : Runs the loaded application
  • new : Clears the current application from MBASIC memory

Also, remember that you can use the Ctrl+C keyboard shortcut to stop a program.

Load and run an application​

There are several preloaded Altair BASIC applications:

  • STARTREK.BAS
  • TICTACTOE.BAS
  • SIMPLE.BAS
  • LOOPY.BAS
  • COUNT.BAS

To load and run one of them:

  1. Enter loadx followed by the application name in quotation marks. For example, for the Tic-Tac-Toe application, enter the following command:

    loadx "TICTACTOE.BAS"

  2. Run the application by using the following command:

    run

  3. The application starts, and you're prompted to go first:

    *** WELCOME TO TIC-TAC-TOE ***
    > YOU ARE X's <
    DO YOU WANT TO GO FIRST?