1971: IBM fashions the floppy
July 8, 1999
by Mary Brandel
(IDG) -- It's ironic that the diskette -- the 3.5-inch, magnetic storage device that's ubiquitous in the computing world today -- is a direct descendant of an 8-inch cousin more closely associated with mainframe data centers.
In fact, the floppy disk was developed in 1971 to solve a problem IBM faced with its System 370 computer: Its operating instructions were stored in semiconductor memory, which got erased whenever the computer was turned off. "If you wanted to restart the computer, you had to reload the control program into memory," says Al Shugart, then product manager for direct-access storage devices at IBM. He later founded Shugart Associates and storage vendor Seagate Technology Inc.
In 1967, the storage group at IBM's San Jose Laboratories was charged with developing an inexpensive device to store and ship microcode for mainframe processors and control units. The device had to cost under $5 to be replaceable, had to be easy to ship and needed unquestionable reliability.
But though Shugart is often credited with inventing the floppy, he's the first to cite David Noble as its true developer. Noble was a senior engineer at the San Jose Labs, and he shouldered the burden as a one-man team with Shugart's oversight.
At first, Noble tried using existing technologies, such as magnetic belts, which are disks similar to those in dictating machines and phonograph records. But it soon became clear that he'd have to start fresh. That's when he proposed the floppy disk.
Within a year's time, Noble -- now working with a larger team -- completed work on what IBM called the "memory disk" -- the diskette. It was a read-only, 8-inch plastic disk coated with iron oxide, weighing just under 2 oz. and capable of storing about 80K bytes. A crucial point in its design was the creation of the protective enclosure. "We had this floppy disk running, but it wasn't in an envelope [plastic jacket]," Shugart says. "The contamination just killed you. Error rates were too high."
So the jacket was lined with a nonwoven fabric that continuously wiped the surface of the disk as it rotated to keep it clean. "That made the thing go," Shugart says.
After passing extensive tests, the floppy was incorporated into the System 370 in 1971; it was also used to load microcode into the controller for IBM's Merlin 3330 disk pack.
But the floppy that emerged in 1971 wasn't the design that became the industry standard, says Jim Porter, now president of Disk/Trend Inc., a market research firm in Mountain View, Calif. At the time, Porter worked at Memorex Inc., an independent manufacturer of floppy disk products.
In 1973, IBM released a new version of the floppy, this time on the 3740 Data Entry System. "The recording format was completely different, and the motor spun in the opposite direction," Porter says. It had read/write capacity and stored 256K bytes.
Users could now enter data onto diskettes rather than punch cards. IBM bragged that the disk could hold as much information as 3,000 punch cards.
After that, the floppy disk market took off. Today, there are still companies that use the 8-inch floppy disk. But that form factor was overshadowed in 1976 with the development of the 5.25-inch floppy, which emerged around the time that personal computing was hitting the scene.
As Porter tells it, Wang Laboratories Inc. wanted to release a desktop computer for word processing and felt the 8-inch size was too big; it started work with Shugart Associates to produce a smaller disk. "One night at a dark bar in Boston, they finally agreed what size the diskette would be. It was a cocktail napkin on the table, which is 5.25 inch," Porter says. "They brought the napkin back to California and told the engineers, 'We really don't know if there's a market for this, but we want you to build a diskette this size.'"
That design eventually gave way to the 3.5-inch diskette, developed by Sony Corp. in 1981. Today, even the 3.5-inch diskette is showing signs of decline, as higher-capacity storage mechanisms such as CD-ROMs and Iomega Corp.'s popular Zip drives take over. Still, the emergence of the floppy went hand-in-hand with the PC revolution -- and helped usher in the era of computing with which we are familiar today.
Brandel is a frequent contributor to Computerworld. Contact her at email@example.com
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