First-Hand:Innovations in Disk Recording, MFM and 3PM Code

Submitted by George V. Jacoby (M '51; SM '58; F '81)

I received the Diploma Ing. degree in electrical engineering from the Technical University of Budapest, Hungary, in 1941.

In the United States, I worked with Honeywell on research and development of industrial instruments, optimizing control methods and servo mechanisms. In 1958, I joined RCA, and worked on various phases of magnetic recording, servo systems and new equalization methods for digital tape recorders and disk files. In 1965-66, I invented and developed into a new product, the Delay Modulation code, with which I doubled reliably the linear bit density of the previously standard Manchester code. Five years later, the same technique became generally accepted by the digital recording industry, as the MFM code.

In 1971, I joined Sperry Univac working as Manager, Advanced Recording Techniques, and later as Senior Professional Consultant. In the mid-1970's, I invented the 3PM code which I provided a reliable fifty percent density increase over the MFM code in a new high density disk file. For this invention, I received the ISS/Sperry Univac Outstanding Contributor's Award in 1978. I hold twenty patents with several pending.