How to Load Software from Tape on Commodore VIC-20

Loading software on the Commodore VIC-20 was a distinct process involving the Datasette cassette recorder. This article outlines the physical connections, the specific BASIC commands required, and the common troubleshooting steps users encountered when transferring programs from tape to memory during the early 1980s.

The primary peripheral for storage on the VIC-20 was the Commodore Datasette 1530. This cassette recorder connected directly to the computer’s expansion port on the side of the machine, eliminating the need for a separate cartridge or user port adapter. Users would insert a standard compact cassette containing the software, ensuring the tape was rewound to the beginning of the data section, which was often preceded by silent leader tape to allow the motor to reach stable speed.

To initiate the loading sequence, the user had to type a specific command into the VIC-20’s BASIC interpreter. The standard command was LOAD"",1, followed by pressing the Return key. The empty quotes indicated that the computer should load the first program it found on the tape, while the number 1 specified the device number for the cassette recorder. Upon executing this command, the screen would display the message PRESS PLAY ON TAPE, prompting the user to physically press the play button on the Datasette.

Once the play button was engaged, the computer would begin reading the audio data. The screen typically changed to display LOADING while the data transferred from the magnetic tape into the system’s RAM. This process was significantly slower than modern standards, often taking several minutes for larger programs. If the load was successful, the computer would display READY. along with the amount of free memory available. If the load failed, an ?LOAD ERROR message would appear, requiring the user to rewind the tape and try again.

After a successful load, the software was not yet running. The user had to type RUN and press Return to execute the program from memory. Reliability was a common concern, as audio tapes were susceptible to magnetic interference, stretching, and degradation. Users often had to adjust the volume knob on the Datasette or clean the read/write heads with isopropyl alcohol to ensure a clear signal path for successful data transmission.