THE FLOPPY DISK INFO PAGE

Inventors Of The Floppy Disk And Drive

In 1971, IBM introduced the first "memory disk" as it was called then or the floppy disk as it is known today. The first floppy was an 8" plastic disk coated with magnetic iron oxide, data was written to and read from the disk's surface. The nickname "floppy" came from it's flexibility, you could bend it. The "floppy disk" was considered a revolutionary device at the time for it's portability, that provided a new and easy physical means of transporting data from computer to computer.

The "floppy" was invented by IBM engineers, led by Alan Shugart. The first disks were designed for loading microcode into the controller of the "Merlin" (IBM 3330) disk pack file (a 100 MB storage device), so in effect the first floppies were used to fill another type of data storage device. Overnight, additional uses for the "floppy" occurred, making it "the new" program and file storage medium.

How does a "floppy" work: it is a circle of magnetic material similar to any kind of recording tape, one or two sides of the disk are used for recording. The "disk drive" grabs the floppy by its' center and spins it like a record inside its' housing. The read/write head (again, much like what we refer to as the head on a tape deck) contacts the surface through an opening in the plastic shell or envelope. The Shugart "floppy" held 100 KBs of data.

In 1976, the 5 1/4" flexible disk drive and diskette was developed by Alan Shugart for Wang Laboratories, Wang wanted a smaller "floppy disk" and drive to use with their desktop computers. By 1978, more than 10 manufacturers were producing 5 1/4" floppy drives.

In 1981, Sony introduced the first 3 1/2" floppy drives and diskettes, which is the "floppy" familiar to today's computer user.

Related Links

Silicon Valley In Depth Interviews Alan Shugart is the king of the disk drive industry and a Silicon Valley legend.

PC Mechanic's Floppy Drive Page Explains what a floppy drive is and contains instructions on how to remove or install one.

The Perfect Floppy Guidelines for floppy disk size, density, and formatting information. 

 

The following first hand information was provided by Richard Mateosian who developed a floppy disk operating system for the first "floppies".

The disks were 8 inches in diameter and had a capacity of 200K, I think. Since they were so large (!) we divided them into four partitions, each of which we regarded as a separate hardware device -- analogous to a cassette drive (our other main peripheral storage device). We used floppy disks and cassettes mostly as paper tape replacements, but we also appreciated and exploited the random access nature of disks.

Our operating system had a set of logical devices (source input, listing output, error output, binary output, etc.) and a mechanism for establishing a correspondence between these and the hardware devices. Our applications programs were versions of HP assemblers, compilers, and so forth, modified (by us, with HP's blessing) to use our logical devices for their I/O functions.

The rest of the operating system was basically a command monitor. The commands had mainly to do with file manipulation. There were some conditional commands (like IF DISK) for use in batch files. The entire operating system and all of the application programs were in HP 2100 series assembly language.

The underlying system software, which we wrote from scratch, was interrupt driven, so we could support simultaneous I/O operations, such as keying in commands while the printer was running, or typing ahead of the 10 character per second teletype. The structure of the software evolved from Gary Hornbuckle's 1968 paper, A Multiprocessing Monitor for Small Machines, and from PDP8-based systems I worked on at Berkeley Scientific Laboratories (BSL) in the late 1960s. The work at BSL was largely inspired by the late Rudolph Langer, who improved significantly on Hornbuckle's model. -Richard Mateosian 

Review Editor, IEEE Micro Berkeley, CA 

website: www.cyberpass.net/~srm/