The History of Magnetic Tape

Oberlin Smith developed the first theory of magnetic tape recording in 1878. It consisted of a string full of iron fillings that passed through a coil of wires. A telephone circuit converted the sound into modulated electrical currents that magnetize and demagnetize the filings as they travel past the coil. When the string is rewound and passed through the coil again, an electrical signal can reproduce the original sound. Unfortunately, Smith never built this device

In 1894, Valdemar Poulsen discovered the principles of magnetic recording.  He created a machine called the Telegraphone and demonstrated a prototype in 1900 at the Paris Exhibition. It was the first successful magnetic sound recorder. At this exhibition, Poulsen recorded the voice of Emperor Franz Joseph, which is still preserved today.

The recorder worked by using a steel wire wrapped in grooves around a cylinder. An electromagnetic head was passed over the wire for recording and playback. 

In 1928, Fritz Pfleumer received a patent that would change everything. The patent was for the application of magnetic powders to a strip of film. This created "tape-recording"

After WWII tape recorders gained commercial appeal. The invention of the 8-track in 1965 revolutionized music recordings.

Tape recordings eventually came to be used as a medium for recording videos and storing computer data.