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Slice of History | April 29, 2016
Magnetic Data Storage
From 1967 through the early 1970s, a number of studies were conducted at JPL with the goal of reducing the size of computer memory and developing miniature storage media for spacecraft computers.
These early tests used Curie-point writing to communicate the bits (ones and zeroes) of computer data. In various tests, a hot wire stylus, an electron beam, or a ruby laser were used to heat tiny dots (around one micrometer in size) on thin ferromagnetic manganese bismuthide (MnBi) film. The material was heated to just above its Curie temperature (the point at which the material is demagnetized) then cooled within a magnetic field, controlling the direction of the magnetization for each dot. The recorded bits of information were observed with polarized light using the Faraday effect. The recorded information could be completely erased by saturating the film in an applied magnetic field, then the recording process could be repeated.
The newest Historical Photo of the Month http://beacon.jpl.nasa.gov/historical-photo-of-the-month shows Dr. George Lewicki and Dr. Dimiter Tchernev who worked on this task. It received NASA funding of $175,000 per year (about $1.2 million in 2016 dollars). The studies were documented in a series of published papers, articles in JPL Space Programs Summaries, and a press release. It was reported that one square inch of magnetic film could hold as much data as computer memory that (in 1967) took up ten cubic feet of space.
For more detailed information about the history of JPL, contact the Library and Archives Reference Desk at (818) 354-4200 or archives@jpl.nasa.gov. If you have questions about the Historical Photo of the Month, please contact archivist Julie Cooper at Julie.A.Cooper@jpl.nasa.gov.
TAGS: MAGNETIC, DATA, STORAGE, HISTORY, COMPUTER, MEMORY, ELECTRON, RUBY, LASER
