Floppy Disk Drives / Floppy Disks

Floppy disk drives were originally introduced commercially as a read-only device in the early 1970s. These early floppy disk drives were used to hold microcode and diagnostics for large IBM mainframe computer systems. These disk drives were using 8-inch floppy diskettes recorded on only one side. By changing these diskettes inside the floppy drive, technicians could easily update the microcode to the latest revisions or load diagnostics easily. The storage capacity of these early read-only drives was less than 100 kilobytes.

In 1973 a new upgraded 8 inch drive with read/write capability and a capacity of about 250 kilobytes began shipping which IBM used in data entry systems. This drive incorporated many technical improvements and became a model for drives still in use today. As time went on, designers learned how to reliably record on both sides of the diskette as well as increase the density of the data recorded on the diskette.

In 1976 smaller 5.25 inch size floppy drives were introduced by Shugart Associates. In a cooperative effort, Dysan Corporation manufactured the matching 5.25 inch flexible floppy diskettes. Originally these drives were available in only a single-sided low density format, and like the first 8 inch models, stored less than 100 kilobytes. Later they received many of the same improvements made to the 8 inch models, and eventually 5.25 inch floppy drives settled at a double-sided, “double density” formatted capacity of about 1.2 megabytes. This drive was used in the IBM-AT personal computer.

Modern floppy drives and diskettes (3.5 inch) have evolved to a much smaller size with larger capacities as well. In 1980, the 3.5 inch floppy drive and diskette was introduced by Sony. During the early 1980’s many competing formats were tried to compete with the 3.5 inch drives. Over time the industry settled on the 3.5 inch format which was standardized and manufactured by many companies. Today’s standard 3.5 inch diskettes hold a formatted capacity of 1.44 megabytes while still using the same basic technology of the second generation 8 inch drives.

The primary factor that caused engineers to reduce the size and cost of floppies was the introduction and evolution of the personal computer. It was in the personal computer market that the low cost, mass produced floppy drive found its first real home. Very quickly, the floppy became the standard
method of exchanging data between personal computers. It also became the popular method of storing moderate amounts of information outside of the computer’s hard drive. Floppy diskettes are small, inexpensive, readily available, easy to store, and have a good shelf life if stored properly. It is a
round, flat piece of Mylar coated with ferric oxide, a rustlike substance containing tiny particles capable of holding a magnetic field, and encased in a protective plastic cover, the disk jacket. Data is stored on a floppy disk by the disk drive’s read/write head, which alters the magnetic orientation of the
particles. Orientation in one direction represents binary 1; orientation in the other, binary 0.