magnetic drums (early patents)

[Mark KAHRS]

A fascinating topic.

Here's a fun patent to read:

http://www.google.com/patents?id=lBJtAAAAEBAJ

Patent number: 2614169
Filing date: Jul 24, 1950
Issue date: Oct 1952
Inventor: A. A. COHEN
Assignee: Engineering Research Asso

Some mention is made of how they made it in 1950.

Coombs original patent:

http://www.google.com/patents?id=gSBXAAAAEBAJ&dq=patent:3119110

Patent number: 3119110
Filing date: May 2, 1949
Issue date: Jan 21, 1964
Inventor: J. M. COOMBS
Assignee: Sperry Rand Corporation

They appear to use spray paint --- not deposition.