Floppy disk drives were originally introduced commercially as a read-only device to hold microcode and diagnostics for large IBM mainframe computer systems in the early 1970s. By changing the diskette inside the floppy drive, service engineers could easily update the microcode to the latest revisions or load diagnostics in an easy and timely manner. These first commercial floppy drives were physically quite large and used 8 inch diskettes recorded on only one side. 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 somewhat of 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 floppy drives were introduced in the 5.25 inch size by Shugart Associates. In a cooperative effort, Dysan Corporation manufactured the matching 5.25 inch 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 enhancements 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. It is also the popular 5.25 inch model still with us today.
Modern floppy drives and diskettes 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. From various companies there were 2.0, 2.5, 2.8, 3.0, 3.25, and 4.0 inch formats! Fortunately for us, over time the industry settled on the 3.5 inch format which is now standardized and manufactured by many companies. Today's standard 3.5 inch diskettes hold a formatted capacity of about 1.5 megabytes while still using the same basic technology of the second generation 8 inch drives.
Although technology has not changed substantially, floppy drives have certainly changed considerably in order to meet the very demanding needs of the marketplace. The primary factor which caused designers 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. Diskettes are small, inexpensive, readily available, easy to store, and have a good shelf life if stored properly.
This article is a discussion of common conventional floppy drives found in today's personal computers. It is important to note that since the early 1980s through the present, high capacity floppy drives have also been introduced to the marketplace. These have come in all three of the popular sizes previously mentioned. Some have achieved data storage capacities and even access times similar to that of small hard drives. Several of these products have come and gone as have some of the companies which produced them. A few designs continue to be popular to this day, especially for certain applications requiring removability but at the same time more storage capacity than the inexpensive common floppy drives can provide. Because of their inherent higher price, few of these high capacity drives have found their way into the mass produced personal computer. These drives are often sold as an add-on (or add-in) accessory for those who need them.
