Wire recording
From Just Solve the File Format Problem
Wire recording is a medium for magnetic sound recording. It was invented in the 1890s, and had its greatest popularity in the late 1940s and early 1950s before magnetic tape eclipsed it in popularity.
Wire recording uses steel (or stainless steel) wire to encode magnetic impulses which could store analog sound signals. It had some advantages in the early days for its compactness and ready availability of the recording medium (it could use wire created for other uses, though specialized recording wire was manufactured). However, as tape drives got more compact, they took over as the dominant medium, allowing for such enhancements as multiple tracks for stereo sound.