Jacob Rabinow (hard disk)

It means inventing is a hell of a lot of fun if you don’t have to make a living at it. It means an inventor can get a job, solving day-to-day problems; the industry says, ‘Fix it but don’t change it,’ so they don’t have to re-tool. Do something new and people say ‘It’s different, but who needs it?’
Jacob Rabinow

Notched-Disk Magnetic Memory Device (c.1951) Courtesy of the National Institute of Standards and Technology
Notched-Disk Magnetic Memory Device (c. 1951)
Courtesy of the National Institute of Standards and Technology

At the end of the 1940s, the American engineer and prolific inventor at the National Bureau of Standards (NBS), Jacob Rabinow (1910-1999), served as a consultant on computer development services for government agencies. Asked to design a machine to record on and read from sheets of magnetic material, he instead proposed adopting discs as used by Valdemar Poulsen in 1898 in his experiments with magnetic recorders. An inductive magnetic read/write head moved in the space between the disks that were mounted on a spindle.

In 1949 Rabinow built an experimental model of his disk-based storage unit, called a Notched-Disk Magnetic Memory Device. Each disk on the machine had a pie section, called a notch, removed. This allowed the read/write head to be moved from one disk to another. Approximately 18 inches in diameter, each disk held about 500000 bits of data.

in August 1952, Rabinow reported experimental work on a notched-disk memory. In March 1951 he filed a patent for a “Magnetic Memory Device” that was granted in October 1954 (US patent Nr. 2690913). NBS policy was that inventions made as part of an employee’s job belonged to the government. As foreign rights remained with the inventor, Rabinow received patents in several foreign countries and sold non-U.S. rights to Remington-Rand for $15000, but the company never used the patent.

IBM 350 Disk Storage
IBM 350 Disk Storage

Several years later, seeking a better method than punched cards, magnetic drums, or tape to store and access information, Reynold Johnson’s team at IBM in San Jose, CA included a description of Rabinow’s device in a 1953 report on “A Proposal for Rapid Random Access File.” They adopted the disk concept as the basis for the RAMAC project that yielded the first commercial hard disk drive in 1956.

In September 1956 IBM introduced a new model computer—the IBM 305 RAMAC (Random Access Memory Accounting) system. Nothing interesting as a design, it was one of the last vacuum tube systems designed by IBM, but… it introduced disk storage technology to the world—IBM 350 Disk Storage (see the nearby photo), so it became a market hit and more than 1000 305s were built before production ended in 1961.

The 350 Disk Storage Unit consisted of the magnetic disk memory unit with its access mechanism, the electronic and pneumatic controls for the access mechanism, and a small air compressor. Assembled with covers, it was 150 cm long, 170 cm high, and 72 cm deep. It was configured with 50 24-inch magnetic disks containing 50000 sectors, each of which held 100 alphanumeric characters, for a total capacity of 5 million characters.

Disks rotated at 1200 rpm, and tracks (20 to the inch) were recorded at up to 100 bits per inch. The execution of a “seek” instruction positioned a read-write head to the track that contained the desired sector and selected the sector for a later read or write operation. Seek time averaged about 600 milliseconds. The disk system cost some $10000.

Over the next several years, as storage memory continued to evolve, the HDD would emerge as the next new, more adaptable solution and would replace many of the earlier, groundbreaking storage technologies.

IBM 3340 Winchester Direct Access Storage Facility (© IBM)
IBM 3340 Winchester Direct Access Storage Facility (© IBM)

During the first several decades of the development of HDDs, IBM was the main innovator. In 1961 it invented heads for disk drives that “fly” on a cushion of air or on “air bearings.” In 1963 it came up with the first removable hard drive, 1311, which has six 14-inch platters and holds 2.6MB. In 1966 it introduced the first drive using a wound-coil ferrite recording head. In 1973, IBM introduced the 3340, or Winchester Direct Access Storage Facility (see the nearby photo). The smaller and lighter 3340 marked the next real evolutionary step in hard disk storage.

The 3340 featured a smaller, lighter read/write head that could ride closer to the disk surface—on an air film 18 millionths of an inch thick, and with a load of fewer than 20 grams. The Winchester disk file’s low-cost head slider structure made it feasible to use two heads per surface, cutting the stroke length in half. The disks, the disk spindle and bearings, the carriage, and the head-arm assemblies were incorporated into a removable, sealed cartridge. A track density of 300 tracks per inch and an access time of 25 milliseconds were achieved. It had three types of data modules: 35 megabytes, 70 megabytes, and 70 megabytes of which 0.5 megabytes were accessible with fixed heads. Two-to-four 3340 drives could be attached to the IBM System/370 Model 115 processor, which had been announced concurrently with the 3340, thus providing a storage capacity of up to 280 million bytes.

IBM continued also to decrease the size of the disks and the platters. In 1979 IBM’s 3370 used seven 14-inch platters to store 571MB, the first drive to use thin-film heads. The same 1979, IBM’s “Piccolo,” which uses six 8-inch platters to store 64MB.

Seagate's ST506 was the first hard disk drive for personal computers
Seagate’s ST506 hard disk

In 1980, a new and unknown company made a small revolution in HDD (hard disk drives) production. Till then only large and well-funded companies could afford to buy a hard disk, but now it has become possible for the broader public. Seagate Technology was founded in 1979 (under the name “Shugart Technology”) by Alan Shugart and Finis Conner. Their first product (released in 1980) was the ST-506 (see the nearby photo), the first hard disc to fit the 5.25-inch form factor of the (by then famous) Shugart “mini-floppy” drive. The ST506 held just 5MB of data and cost $1500. The hard disc was a hit and was later released in a 10-megabyte version, the ST-412.

In 1983 the company Rodime released the first in the world 3.5-inch hard drive. The company engineers used the 3.5-inch form factor of the floppy disk drives again. The RO352 includes two platters and stores 10MB. In 1998 IBM announced its Microdrive, the smallest hard drive to date, designed to fit in a CompactFlash (CF) Type II slot. It was launched in 2 models—170 MB and 340 MB.

Despite computer technology and other sectors of the tech industry developing exponentially faster, magnetic hard disk drives (HDDs) are still the technology of choice for storing computer and server data. As the storage market is changing, it’s very likely that hard drives will be replaced by future technology. According to some research, the use of hard disks could come to an end soon. Solid-state drives (SSDs) are already replacing hard disks as a primary storage source for computers.

Biography of Jacob Rabinow

Jacob Rabinow (1910-1999)
Jacob Rabinow (1910-1999)

Jacob Rabinow was born as Яков Рабинович in the Jewish family of Aaron and Helen Rabinovich (born 1882) in Harkov, Russian Empire (now Kharkiv, Ukraine), on 8 January 1910. Арон Рабинович (Aaron Rabinovich) married Елена Флайшер (Helen Fleisher) from Кременчук (a city in central Ukraine) in 1908 and they had two sons: David (born 1908), and Jacob. In 1914, the family moved to Kustanay, Siberia (now Kostanay, Kazakhstan), where Aaron Rabinovich established a small shoe factory. The talent of an inventor in the young Jacob woke up under the influence of science fiction books, especially Jules Verne. He was also captivated by the machinery in their factory and by his father’s attempts to automate some production operations.

After the Revolution struck in 1917, Aaron lost the factory, but the revolutionaries didn’t molest him because he was a Social Democrat, and apparently, he was neutral enough so that neither the Communists nor the White Guards bothered him much, except that the factory was confiscated. In 1918, while in Kustanay, the 8-year-old Jacob made his first invention–the machine (“a couple of ropes with a stick in between”) to throw rocks. The young boy was quite pleased with his brilliant idea until an adult informed him that his rock thrower was actually a Roman ballista, which had been invented some 2000 years before 🙂

In 1919, when the Civil War was still raging between the Whites and the Reds, the Rabinovich family took whatever they could carry and left for China. Unfortunately, Aaron caught typhus just as they arrived at Harbin in China, and died about a week later. The family (Helen Rabinovich, Jacob, and his two years older brother David), had some money and they lived in China for two years until finally got permission to travel to the United States where they had relatives. In June 1921 they settled in New York, where Helen opened a corset shop in Brooklyn. Jacob was put directly into fourth grade, although he didn’t understand a word of English, but at the end of a few months this, he learned very quickly and became a very good mathematics student. He also began to play with the radio just about the same time and built his first professional radio set for his teacher, a one-tube receiver for $11. Jacob never stopped building radio equipment since then, and during the Great Depression, he worked in a radio factory.

Jacob got out of high school in 1927, then he took half a year to work full-time, to earn a few bucks, and then he entered New York City College. At that time he was naturalized and shortened his surname from Rabinovich to Rabinow. When the Depression wiped out his mother’s shop in Brooklyn, “Kuba,” as she called Jacob, had to borrow the $62 tuition for graduate engineering school at City College. Jacob graduated from City College with a Bachelor’s Degree in Engineering in 1933, and a Master’s Degree in Electrical Engineering in 1934. In fact, initially, he had taken a “straight” B.S. at CCNY because he had been told repeatedly that there was no chance in America for a Jewish engineer, but when the corset shop failed, Kuba decided: “If I’ll starve, I’ll starve doing something I like.” He abandoned his compromise goal of being a teacher and switched back to engineering.

His career as an inventor Jacob began when he was hired as a mechanical engineer in 1938 by the National Bureau of Standards (now the National Institute of Standards and Technology, or NIST). He made many developments there, mainly in defense systems, and eventually became Chief of the Electro-Mechanical Ordnance Division at NBS before leaving in 1954 to form his own company, Rabinow Engineering. He also became interested in a microfilm reader envisioned by Vannevar Bush called the Rapid Selector, and this led to his more general interest in reading machines.

Jacob Rabinow (1910-1999)
Jacob Rabinow (1910-1999)

Rabinow earned a total of 229 United States patents on a variety of mechanical, optical, and electrical devices. Among them are the first disc-shaped magnetic storage media for computers (1954), the magnetic particle clutch (1956), the first straight-line phonograph (1959), the first self-regulating clock (1960), and his famous “reading machine” (1960) which was the first to use the “best match” principle and was the basis for the reading, sorting and processing machines used today by banks and post offices. Rabinow had shelves of notebooks full of perhaps 2000 yet unpatented ideas.

In 1964, Rabinow’s company joined Control Data Corporation (Centers for Disease Control and Prevention), and until 1972 he was Vice President of the Centers for Disease Control and Prevention and head of the Rabinow Advanced Development Laboratory. In 1968 Rabinow formed the RABCO company to manufacture straight-line phonographs, and the company was later bought out by Harman Kardon Corporation. In 1972 Rabinow returned to NBS where he was Chief Research Engineer until his retirement in 1989.

Rabinow published his book, Inventing for Fun and Profit, in 1989. He also delivered many speeches and lectures on inventions and technology, as a guest at many educational institutions and on several television and radio shows. He also served on the board of trustees for Science Service, now known as Society for Science & the Public, from 1971 to 1973. Rabinow has been listed as a noteworthy Electrical engineer and consultant by Marquis Who’s Who.

On 26 September 1943, Jacob Rabinow married Gladys Lieder (1918-2018), a math teacher and statistician, and they had two daughters—Jean Ellen, and Clare Lynn.

The remarkable engineer and inventor Jacob Rabinow died on 11 September 1999 (aged 89) in Fairfax County, Virginia, USA.