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Micron Blog

Part 2: Magnetic Drum Memory

Magnetic Drum Memory: A Forerunner of the Modern Hard Drive

  1. Tape Drives
  2. Magnetic Drum Memory
  3. The Birth of the Hard Drive
  4. The 5.25-inch Hard Drive
  5. Limitations of the HDD
  6. The RAM SSD & NAND
  7. NAND in SSDs

Almost in parallel to tape drive development, magnetic drum memory was  finding use as a data storage media.

While working under a contract with IBM (The Tabulating Machine Company) in 1928 [14], Austrian engineer, Gustav Tauschek, who was self-taught [15], developed the first electromagnetic drum storage device. He received a U.S. patent for his work on drum storage in 1932, but his invention would not become generally popular until the 1950s and 1960s.

Figure 4: "Setting Device for Calculating Machines and the Like" from Tauschek’s 1932 U.S. Patent

In its most basic form, magnetic drum memory is simply a metal drum or cylinder coated with a ferromagnetic material. Stationary write heads emit an electrical pulse, changing the magnetic orientation of a particle at a given position on the drum. The read heads, which are also stationary, recognize a particle's orientation as either a binary 1 or 0. Tauschek's prototype could store 500,000 bits across the drum's total surface for a capacity of about 62.5KB.[16]

The Workhorse of Modern Industry

In the 1950s, the world of computers was changing, and while it would be decades before the personal computer completely revolutionized the business world, companies like IBM were making huge strides in electronic data processing.  It was against this backdrop that the engineers at IBM's Endicott, New York, laboratory launched the 650 Magnetic Drum Data Processing Machine in 1953 [17].

Originally, IBM believed that the total market for 650's might be 50 installed units. But in less than two years, 75 of the drum-based machines had been installed and the company expected to install more than 700 more units over the next few years [18].

"The development requirement underlying the 650 was for a small, reliable machine offering the versatility of a stored-program computer that could operate within the traditional punched card environment. IBM—and the industry—wanted a machine capable of performing arithmetic, storing data, processing instructions and providing suitable read-write speeds at reasonable cost. The magnetic drum concept was seen as the answer to the speed and storage problems."[19]

By 1962, when IBM stopped manufacturing the 650, more than 2,000 units had been sold, making it the most popular computing machine of the era. [20] The principles at work in magnetic drum memory would help to lead researchers to another and perhaps even more important innovation: the hard disk drive.

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Notes [14]Gustav Tauschek, "Setting Device for Calculating Machines and the Like," U.S. Patent 1880523 (October 4, 1932). [15] Brian Randell, "The History of Digital Computers," University of Newcastle upon Tyne (1974):page 4 [16] "People Behind Informatics," Universitat Klagenfurt, downloaded from and "Lecture 16: The First Modern Computers," School of Analytic Studies & Information Technology, York University, downloaded from [17] "The IBM 650, Workhorse of Modern Industry," IBM, Armonk, N.Y. downloaded from [18] "The IBM 650, Workhorse of Modern Industry," IBM, Armonk, N.Y. downloaded from [19] "The IBM 650, Workhorse of Modern Industry," IBM, Armonk, N.Y. downloaded from [20] "The IBM 650, Workhorse of Modern Industry," IBM, Armonk, N.Y. downloaded from

About Our Blogger

Dean Klein

Dean Klein is Vice President of Memory System Development at Micron Technology. Mr. Klein joined Micron in January 1999, after having held several leadership positions at Micron Electronics, Inc., including Executive Vice President of Product Development and Chief Technical Officer. He also co-founded and served as President of PC Tech, Inc., previously a wholly-owned subsidiary of Micron Electronics, Inc., from its inception in 1984. Mr. Klein’s current responsibilities as Vice President of Memory System Development focus on developing memory technologies and capabilities.

Mr. Klein earned a Bachelor of Science degree in electrical engineering and a Master of Electrical Engineering from the University of Minnesota, and he holds over 220 patents in the areas of computer architecture and electrical engineering. He has a passion for math and science education and is a mentor to the FIRST Robotics team ( in the Meridian, Idaho school district.

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