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Inventors Of The Modern Computer
The Floppy Disk And Drive
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 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. The floppy
disk was considered a revolutionary device at the time for it's portability
which 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 microcodes 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 were discovered, 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, much like 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 had 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. This is the floppy familiar to
today's computer user.
| Editors note: 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
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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 DrivePage
Explains what a floppy drive is and contains instructions on how to
remove or install one.
all artwork ©MaryBellis
except waving floppy©ByDezign
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