Gustav Tauschek in 1933
Gustav Tauschek in 1933

Magnetic drum memory was a magnetic data storage device. Since its founding in 1932, the drum became the backbone of many early computers. It formed the primary working memory of the computer and sometimes served as the secondary storage.

But later on, the magnetic core memory and hard disk drives came into existence and replaced the drums. That’s because they offered better size balance, reliability, high speed, and had the potential for further enhancements. Besides, they had a denser storage capacity than drums. And due to that, the manufacturing of drums stopped in the 1970s.

6 Facts about the Magnetic Drum Memory

  • Magnetic drum memory was the first magnetic data storage device and an early computer memory form to be created.
  • Gustav Tauschek is the mind behind the famous magnetic drum memory.
  • The drum memory was the first magnetic data storage device for computers.
  • Magnetic drum memory had a capacity of about 62.5 KB.
  • The data storage device could store 500000 bits across its total surface
  • The principles at work in magnetic drum memory helped to lead researchers to create another and even more important innovation: the hard disk drive.

Magnetic Drum Memory History 

Magnetic drum memory was the first magnetic data storage device and an early computer memory form to be created. The data storage memory was designed and developed by the Austrian engineer GustavTauschek in 1932 in Austria. 

The device played a vital role in computer memory development and was initially used in Atanasoff-Berry computers (ABC computer) in 1942. However, most people and computer users adopted its use between 1950 and 1960.

Gustav Tauschek, born on April 29, 1899, was an exceptional self-taught Viennese engineer who also invented many other devices and systems for punch card machinery. He is also the mind behind the first OCR (Optical Character Recognition) machine, better known as the reading machine, invented in 1928.

While working for Rheinmetall in Sömmerda, Germany, between 1926-1930, Tauschek created a complete accounting system based on punched cards. However, the accounting system was never mass-produced. 

In the spring of 1928, Rheinmetall came up with a subsidiary company for developing new punch card-based machines. But towards the end of the same year, IBM bought the subsidiary, assuming its monopoly on the market. In the process, Tauschek received a five-year contract and sold to IBM about 169 patents in his lifetime.

In 1932, Tauschek obtained a US patent for his magnetic drum device (see US patent 1880523 and the lower patent drawing).

Tauschek patent drawing
Tauschek patent drawing from 1929 of magnetic drum memory device

In its basic form, the magnetic drum memory had a metal cylinder coated with a ferromagnetic recording material.

Many considered it a precursor to the hard disk drive (HDD) but in the drum form rather than a flat disk. Most designs featured one or more rows with fixed read-write heads, designed along the drum’s long axis and each one occupying a track.

The drum’s controller task was to select the right head and then wait for the appearance of data beneath it as the drum rotated. At the same time, stationary write heads emitted an electrical pulse to alter the magnetic orientation of a particle at a specific position on the drum.

On the other hand, the read heads, also stationary, recognized a particle’s orientation as binary 1 or 0. Tauschek’s prototype could store 500000 bits across the drum’s total surface. It had a capacity of about 62.5 KB.

As late as 1980, the magnetic drums were still used as the main memory by many people with the PDP-11/45 machines. Drums for swapping were also still in use at various original UNIX sites.

Besides, the minuteman ICBM launch control centres continued to use the magnetic drum memory units after adopting them in the early 1960s. They only changed after the REACT upgrades that occurred in the mid-1990s.

In the modern-day, the BSD Unix and its descendants is the name of the default swap device. It originates from the use of the drum secondary storage devices as backup storage for pages in virtual memory.

By following the principles at work in magnetic drum memory, researchers have created another more advanced innovation named the hard disk drive. However, there are slight differences between the magnetic drum memory and the modern hard disk drive. 

For instance, the magnetic drum heads did not have to move to the track access, and the controller waited for the data to appear beneath the relevant head as the drum turned. With the modern disk drive, the disk head takes a particular time to move into its place. Also, the performance of a drum with fixed heads is entirely determined by its rational speed.

Magnetic Drum Memory: How It Worked

Magnetic drum memory consisted of a metal cylinder or drum coated with a ferromagnetic recording material. In between the drum, there were rows fitted with fixed read-write heads arranged along the drum’s axis, occupying each track. 

magnetic digital storage drum memory
A magnetic digital storage drum memory from 1950s

The memory device also had a controller whose major work was to select the proper head and wait for data to appear beneath it as the drum rotated.

On the other hand, the stationary write-heads emitted an electrical pulse, changing the magnetic orientation of a particle at a specific position on the drum. The process generated a series of binary digits. And the read heads, which were also stationary, recognized a particle’s orientation as either a binary 1 or 0.

Magnetic Drum Memory: Historical Significance

Through the invention of the magnetic drum memory, many developers dwelled on its principles and designed the various modern random access memory cards and secondary storage devices, better known as hard disk drives for their computers.

The modern hard disk drives also have magnetic storage systems with more premium features. With the many advancements, computer manufacturers have streamlined their services to produce computer devices able to accommodate the current hard drive disks.

Magnetic Drum Memory Explained – Everything You Need To Know FAQs (Frequently Asked Questions) 

What is Magnetic Drum Memory?

A Magnetic Drum Memory refers to the magnetic data storage device used by early computers. It functioned as the main working memory, similar to the modern RAM cards (random access memory). In other instances, the magnetic drum memory served as secondary storage.

How does Magnetic Drum Memory Work?

The device consists of a metal drum coated with a ferromagnetic recording material. Its controller selects the proper head and waits for the data to appear beneath it as the drum turns. On the other hand, stationary write heads release electrical pulse, changing the magnetic orientation of a particle at a given position on the drum. Finally, the read heads recognize a particle’s orientation as, either binary 1 or 0.

Who invented Magnetic Drum Memory?

The magnetic drum memory was invented by the Austrian engineer Gustav Tauschek (1899-1945) in 1932 in Austria. Tauschek was a genius self-taught Viennese engineer, who besides the drum-memory, invented also many devices and systems for the punch-card machinery, as well as the first OCR (Optical Character Recognition) the machine in 1928, the so-called Reading Machine.

When was Magnetic Drum Memory invented?

The magnetic drum memory was invented in 1932.

What Did the Magnetic Drum Do?

The drum memory served as a magnetic storage device for most early computers. It could be used as the main working memory or as secondary storage.

What computer generation used the magnetic drum memory?

Atanasoff berry computer

Is magnetic drum memory still used?

No, subsequent advancements in hard disk drives and magnetic-core memory led to the decline of the magnetic drum as storage for computers. In fact, they ceased to be manufactured by the 1970s.

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