page_title: History of the floppy disk
section_title: The ​5 1⁄4-inch minifloppy
hierarchical_section_title: History of the floppy disk / The ​5 1⁄4-inch minifloppy
caption_attribution_description: English: 5.25-inch white floppy disk, front. Lietuvių: Balto 5,25 colio diskelio priekis.
context_page_description: A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium encased in a rectangular plastic carrier. It is read and written using a floppy disk drive. Floppy disks were an almost universal data format from the late 1970s into the 1990s, used for primary data storage as well as for backup and data transfers between computers.
  In 1967, at an IBM facility in San Jose, work began on a drive that led to the world's first floppy disk and disk drive. It was introduced into the market in an 8-inch format in 1972. The more conveniently sized ​5 ¹⁄₄-inch disks were introduced in 1976, and became almost universal on dedicated word processing systems and personal computers. This format was more slowly replaced by the ​3 ¹⁄₂-inch format, first introduced in 1982. There was a significant period where both were popular. A number of other variant sizes were introduced over time, with limited market success.
  Floppy disks remained a popular medium for nearly 40 years, but their use was declining by the mid- to late 1990s.
context_section_description: In a 1976 meeting, An Wang of Wang Laboratories informed Jim Adkisson and Don Massaro of Shugart Associates that the 8-inch format was simply too large and expensive for the desktop word processing machines he was developing at the time, and argued for a US$100 drive. 
  According to Massaro, Adkisson proposed a smaller size and began working with cardboard mockups before the Wang meeting. George Sollman suggests the size was the average of existing tape drives of the era. It is an urban legend that the physical size came about when they met with Wang at a bar in Boston; when he was asked what size would be appropriate, Wang pointed to a cocktail napkin—there was no such meeting.
  The new drive of this size stored 98.5 KB, later increased to 110 KB by adding five tracks.
  The 5 ¹⁄₄-inch (133 mm) drive was considerably less expensive than 8-inch drives, and soon started appearing on CP/M machines.
  Shugart's initial 5.25" drive was the 35-track, single-sided SA-400, which was widely used in many early microcomputers, and which introduced the 34-pin interface that would become an industry standard. It could be used with either a hard or soft sectored controller, and storage capacity was listed as 90k (single density) or 113k (double density). The drive went on sale in late 1976 at a list price of $400, with a box of ten disks at $60. The new, smaller disk format was taken up quickly, and by 1978 ten different manufacturers were producing 5.25" drives. At one point, Shugart was producing 4,000 drives a day, but their ascendancy was short-lived; the company's fortunes declined in the early 1980s. Part of this was due to their failure to develop a reliable 80-track drive, increasing competition, and the loss of several lucrative contracts—Apple by 1982 had switched to using cheaper Alps drive mechanisms in their computers, and IBM chose Tandon as their sole supplier of disk drives for the PC. By 1977 Shugart had been purchased by Xerox, who closed the operations in 1985 and sold the brand to a third party.
  In 1978 I.T.C. (later called Verbatim), had approximately 35 percent of the estimated $135 million floppy disk market and sold 5.25 disks in large quantities for $1.50 each (equivalent to $6 in 2019).
  Apple purchased bare SA-400 drive mechanisms for their Disk II drive, which was then equipped with a custom Apple controller board and the faceplate stamped with the Apple logo. Steve Wozniak developed a recording scheme known as Group Code Record which allowed 140k of storage, well above the standard 90–113k, although the price of double density controllers fell not long after the Disk II's introduction. GCR recording used software means of detecting the track and sector being accessed, hence there was no need of hard sectored disks or even the index hole.
  Commodore also elected to use GCR recording (although a different variation not compatible with Apple's format) in their disk drive line. Tandy however used industry-standard FM on the TRS-80's disk drives, with stock Shugart SA-400s, and so had a mere 85k of storage.
  These early drives read only one side of the disk, leading to the popular budget approach of cutting a second write-enable slot and index hole into the carrier envelope and flipping it over (thus, the “flippy disk”) to use the other side for additional storage. This was considered risky by some as single sided disks were only certified by the manufacturer for single-sided use. The reasoning was that, when flipped, the disk would spin in the opposite direction inside its cover, so some of the dirt that had been collected by the fabric lining in the previous rotations would be picked up by the disk and dragged past the read/write head.
  Although hard sectored disks were used on some early 8" drives prior to the IBM 33FD (May 1973), they were never widely used in 5.25" form, although North Star clung to the format until they went bankrupt in 1984.
  Tandon introduced a double-sided drive in 1978, doubling the capacity, and this new “double sided double density” (DSDD) format increased capacity to 360 KB.
  By 1979, there w
caption: White ​5 1⁄4-inch floppy disk.
exif: {}