Why, sometimes I’ve believed as many as six impossible things before breakfast.
Alice in Wonderland, Lewis Carroll
In the 1960s, the engineers at IBM who had developed the RAMAC computer and the early disk drives understood the significance of small, removable disk memory. In 1967, IBM gave their San Jose, California storage development center a task to develop a simple and inexpensive system for loading microcode into their System/370 mainframes in a process called Initial Control Program Load (ICPL). Usually, this task would be done with tape drives which almost all 370 systems included, but tapes were large, unhandy, and slow. In fact, the floppy disk was initially designed for use in loading microcode into the controller for the “Merlin” (IBM 3330) disk pack file. IBM also wanted something faster and lighter that could also be sent out to customers with software updates for some $5.
At the end of 1967 IBM Direct Access Storage Product Manager Alan Shugart, an American engineer, entrepreneur, and business executive whose career defined the modern computer disk drive industry, assigned the job to a small team of engineers under the leadership of the experienced David L. Noble. During 1968 Noble’s team experimented with tape cartridges, RCA 45-rpm records, dictating belts, and a magnetic disk with grooves developed by Telefunken, but finally created their own solution—the floppy disk (actually they called it the “memory disk”). IBM introduced the read-only and holding 80 kilobytes diskette commercially in 1971, using the name Minnow, and shipped it as the 23FD, a standard part of System 370 processing units and for other products. The first floppies were bare, but they got dirty easily, so the team packaged them in slim but durable envelopes equipped with an innovative dust-wiping element, making it possible to handle and store them easily. It was a plastic disk 8 inches in diameter, 1.5 mm thick, coated on one side with iron oxide, attached to a foam pad, and designed to rotate on a turntable driven by an idler wheel. In March 1970 IBM applied for a patent and U.S. patent Nr. 3678481 was granted in 1973.
A read-only magnetic head was moved over the disk by solenoids and read data from tracks prerecorded on the disk at a density of 1100 bits per inch. The disk was “hard-sectored” with 8 holes around the center to mark the beginning of data sectors. At first, its capacity was only 81.6 KB, but by February 1969 Noble had doubled the thickness of the plastic base to 3 mm and coated both sides to add more capacity. In June 1969, the Minnow was added to the IBM System 370 and soon began to be used by other divisions in IBM. In 1970, the name was changed to Igar and Noble had a staff of 25 engineers to help him make improvements. By 1971, Igar became the 33FD disk drive and the 8-inch floppy disk became the Type 1 diskette. The speed was 360 rpm, with a head access time of 50 milliseconds. The 8 hard sector holes were replaced by a single index hole for “soft sectors” or “IBM sectoring” across 77 tracks. In 1976 the 43FD disk drive was sold with dual heads to read and write to both sides of the diskette. A new model 53FD was added in 1976 that used modified frequency modulation to record double-density on both sides, resulting in a capacity of 1200 KB.
In 1969 Alan Shugart left IBM and moved to Memorex where in 1972 his team shipped Memorex 650, the first read-write floppy disk drive. The 650 had a data capacity of 175 kB. Later Shugart established a new company, and in 1975, Shugart Associates produced an 8-inch floppy disk to hold 800k that offered for the first time a low-cost drive for the emerging personal computer market. In 1976, Jim Adkisson and Don Massaro, Shugart engineers, sat down for lunch with a customer (An Wang of Wang Laboratories), who complained that the 8-inch drive was too big for the personal computer. When Adkisson asked what the size should be, An pointed to a napkin on the table and said, “About that size.” Adkisson returned to the Shugart lab with the napkin and designed the 5.25-inch floppy drive, introduced in December 1976 as the model SA-400 (see the nearby photo) with a capacity of 110 KB (single-side single-density) and price of $390. The model became one of Shugart’s best sellers, with shipments that rose to 4000 drives per day. The company turned to Matsushita in Japan to help make the drives, starting that company on its rise to becoming the largest floppy drive manufacturer in the world.
Sony developed a 3.5-inch floppy drive (see the nearby photo) by 1980 and began a two-year effort to make it the U.S. floppy disk standard. They stored 438Kb of data, and later 720K (double-density) and 1.44MB (high-density). Sony declared that its new drive was smaller, faster, better protected (it had a hard-shell cartridge and an automatic shutter, that closed over the recording surface when it was removed from the drive), and could fit in a shirt pocket. Initially, there were different incompatible disk sizes (3-inch of Hitachi, 3.8-inch of Canon, 4-inch of IBM, etc.), but Sony’s soon became dominant. Sales of the 3.5-inch floppy began to surpass the 5.25-inch version by 1989, and Japanese companies would drive most U.S. disk producers out of the market. For many years 3.5-inch floppy disks were as plentiful as plastic bottles and were the most common PC storage disk.
By the early 1990s, the increasing software size meant large packages like Windows or Adobe Photoshop required a dozen disks or more. In 1996, there were an estimated five billion standard floppy disks in use. Then, the distribution of larger packages was gradually replaced by CD-ROMs, DVDs, and online distribution. As important as they were, by the late nineties floppy disks were on their way out. Re-writable CDs were introduced that had the same capabilities as floppy disks but were more reliable. It is believed that 2011 is the year the floppy disk finally died, and 40 years is a very long lifespan for a technical gadget.
Interestingly, a Japanese inventor, Yoshiro Nakamatsu, claims to have invented core floppy disk technology in 1952 and further claims to have later licensed 16 patents to IBM for the creation of the floppy disk, however, there is no reliable source to support his assertions.
Biography of David Noble
David L. Noble was born in Naugatuck, CT, on 16 July 1918. In 1940 he graduated with B.E.E. in electrical engineering from and later taught at Rensselaer Polytechnic Institute in Troy, NY. During WWII, Noble served as an officer in the U.S. Naval Reserve where he worked in cryptology, and was recognized for invaluable service to Navy code-breaking activities (just like other computer pioneers like Alan Turing).
Following the war, Noble was an original staff member of Engineering Research Associates in St. Paul, MN, and worked on special-purpose computers. In 1949 he was employed by Remington Rand Laboratory for Advanced Research in Norwalk, CT, where he worked on automatic business machines. In 1956, Noble joined IBM Corporation in Poughkeepsie, NY, where he worked on magnetic ink character sensing equipment for banks, and performed technical assignments related to high-speed data processors. From 1960 to his retirement in 1978, Noble was located at IBM’s Development Laboratory in San Jose, CA, where he was engaged in the development disciplines of magnetic recording, direct access disk files, and data distribution devices. In 1974, Noble received an IBM Outstanding Contribution Award for the development of the flexible floppy disk and its associated disk drive mechanism. In his retirement years, his concentration turned to the study of artificial intelligence and the design of neural networks. A licensed amateur radio operator, Noble volunteered his time with the California Div. of Forestry VIP program and was a former member of Kiwanis.
In 1944 David Noble married Dorothy Beavers Noble (1920-2008), a teacher, born in St. Louis, MO. They had two daughters—Ann Noble Fielder, and Lynn J Noble. David Noble died on 25 April 2004 in his home in Monte Sereno, California.