computer science

History of the floppy disk

History of the floppy disk is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand History of the floppy disk rather than just read about it. In short: A floppy disk is a disk storage medium composed of a thin and flexible magnetic storage medium encased in a rectangular plastic carrier. It is read and written using a floppy disk drive (FDD).

Key takeaways

History of the floppy disk belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect History of the floppy disk to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of History of the floppy disk from memory before moving on to harder problems.

Reference excerpt

A floppy disk is a disk storage medium composed of a thin and flexible magnetic storage medium encased in a rectangular plastic carrier. It is read and written using a floppy disk drive (FDD). Floppy disks were an almost universal data format from the 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, California, 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 (203 mm) format in 1971. The more conveniently sized 5¼-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 3½-inch format, first introduced in 1982. There was a significant period where both were popular. The dimensions are nominal, the actual cartridge sizes are 130 mm (5.12 in) and 90 mm (3.54 in) respectively, while the disks themselves are somewhat smaller. 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. After 2000, floppy disks were increasingly rare and used primarily with older hardware, especially with legacy industrial and musical equipment. Sony manufactured its last new floppy disks in 2011.

8-inch floppy

Origin as a read-only floppy disk IBM's decision in the late 1960s to use RAM as the writeable control store for future systems and control units created a requirement for an inexpensive and reliable read-only device and associated medium to store and ship the control store's microprogram, and at system power-on to load the microprogram into the control store. The objective was a read-only device costing less than $200, and a medium costing less than $5. IBM San Jose's Direct Access Storage Product Manager, Alan Shugart, assigned the job to David L. Noble, who tried to develop a new-style tape for the purpose, but without success. The project was reassigned to Donald L. Wartner, 23FD Disk Drive manager, and Herbert E. Thompson, 23FD Disk manager, along with design engineers Warren L. Dalziel, Jay Brent Nilson, and Ralph Flores; and that team developed the IBM 23FD Floppy Disk Drive System (code name Minnow). The disk is a read-only, 8-inch-diameter (200 mm) flexible diskette called the "memory disk" holding 80 kilobytes of data. Initially the disk was bare, but dirt became a serious problem so they enclosed it in a plastic envelope lined with fabric that would remove dust particles. The Floppy Disk Drive Patent #3,678,481 was issued July 18, 1972 with named inventors Warren L. Dalziel, Jay. B. Nilson, and Donald L. Wartner. IBM introduced the diskette commercially in 1971. The new device first shipped in 1971 as the 23FD, the control store load device of the 2835 Storage Control Unit. and then as a standard part of most System 370 processing units and other IBM products. Internally IBM used another device, code named Mackerel, to write floppy disks for distribution to the field.

Enhancement into a read/write floppy disk Other suppliers recognized the opportunity for a read/write FDD in applications such as key entry and data logging. Shugart, by then at Memorex shipped the Memorex 650 in 1972, the first commercially available read-write floppy disk drive. The 650 had a data capacity of 175 kB, with 50 tracks and 8 sectors per track. The Memorex disk was hard sectored, that is, it contained 8 sector holes (plus one index hole) at the outer diameter (outside data track 00) to synchronize the beginning of each data sector and the beginning of a track. Most early 8" disks were hard sectored, meaning that they had a fixed number of disk sectors (usually 8, 16, or 32), marked by physical holes punched around the disk hub, and the drive required the correct media type for its controller. IBM was developing a read/write FDD but did not see a market opportunity for such a device so came close to cancelling the project. A chance encounter in San Jose between IBM's Jack Harker and Don Stephenson the site manager of IBM's General Systems Division, Rochester MN, who needed a product to compete with Mohawk's key to tape system led to the production of IBM's first read/write FDD, the 33FD code named "IGAR." The 33FD first shipped in May 1973 as a component of the 3740 Data Entry System, designed to directly replace IBM's punched card ("keypunch") data entry machines. The medium sold separately as "Diskette 1". The new system used a soft sector recording format that stored nearly 250 kB on a disk. Drives supporting this format were offered by a number of manufacturers and soon became common for moving smaller amounts of data. This disk format became known as the Single Sided Single Density or SSSD format. It was designed to hold the same amount of data as 3000 punch cards.

… excerpt ends here. Continue reading the full article.

Illustrations

History of the floppy disk: A double-density 5¼-inch disk with a partly exposed magnetic medium spun about a central hub. The cover has a cloth liner to brush dust from the medium. Note the “write-enable slot” to the upper right and the hole next to the hub that gives access to the index hole in the disk. — A double-density 5¼-inch disk with a partly exposed magnetic medium spun about a central hub. The cover has a cloth liner to brush dust from the medium. Note the “write-enable slot” to the upper right and the hole next to the hub that gives access to the index hole in the disk.

Worked examples

Example 1 — a first encounter with History of the floppy disk

Start with the simplest possible case. Write down what History of the floppy disk claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to History of the floppy disk before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about History of the floppy disk ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of History of the floppy disk

In research: History of the floppy disk appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses History of the floppy disk in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: History of the floppy disk is common in secondary-school and first-year university syllabi. It links to neighbouring topics Floppy disk computer storage, Floppy disk drives, History of Silicon Valley, so understanding it makes those chapters shorter.
In everyday life: Look for History of the floppy disk outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study History of the floppy disk in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what History of the floppy disk means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain History of the floppy disk out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is History of the floppy disk in simple terms?

A floppy disk is a disk storage medium composed of a thin and flexible magnetic storage medium encased in a rectangular plastic carrier. It is read and written using a floppy disk drive (FDD).

Why does History of the floppy disk matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study History of the floppy disk?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on History of the floppy disk.