Tub file

The tub file was a technique used in the punched card era to speed generation of data files. Multiple copies of frequently used cards were prepunched and stored in trays with index tabs between card sets, arranged so that cards would be easy to find. For example a wholesaler might have a tub file with cards for frequent customers and for each inventory item. Instead of keypunching a set of cards for each purchase order, a clerk would pull out a customer card and then a card for each item that customer ordered. The resulting deck could then be run through a tabulating machine to produce an invoice. This technique was an early form random access memory and was the initial inspiration for the invention of the hard disk at IBM's San Jose Laboratory, what eventually became the IBM 305 RAMAC.

References

Tub (unit)

Tub was a unit of capacity or of weight used in Britain and elsewhere.

British unit for butter and cheese

British laws for the sale of goods defined a tub of butter as a receptacle of a size which could contain 84 pounds of butter.

Definition

1 tub of butter or cheese = 84 pounds

Conversion

1 tub = 1.5 Firkin (1 Firkin = 56 lbs)

Metric equivalent

1 tub = 38 kg

Other commodities

The Oxford English Dictionary has quotations illustrating other values of a "tub" as a unit:

In Newfoundland, Canada, a tub of coal was defined as 100 pounds, while a tub of herrings was 16 Imperial gallons and a tub of salt was 18 Imperial gallons.

References

File

File or filing may refer to:

Services

Information

Computing

Other uses

See also

Glossary of chess

This page explains commonly used terms in chess in alphabetical order. Some of these have their own pages, like fork and pin. For a list of unorthodox chess pieces, see Fairy chess piece; for a list of terms specific to chess problems, see Glossary of chess problems; for a list of chess-related games, see Chess variants.

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

[adjective: prophylactic] Prophylactic techniques include the blockade, overprotection, and the mysterious rook move.

Q

R

S

T

U

V

W

X

Z

References

Bibliography

Computer file

A computer file is a resource for storing information, which is available to a computer program and is usually based on some kind of durable storage. A file is "durable" in the sense that it remains available for other programs to use after the program that created it has finished executing. Computer files can be considered as the modern counterpart of paper documents which traditionally are kept in office and library files, and this is the source of the term.

Etymology

The word "file" was used publicly in the context of computer storage as early as February, 1950. In an RCA (Radio Corporation of America) advertisement in Popular Science Magazine describing a new "memory" vacuum tube it had developed, RCA stated:

In 1952, "file" was used in referring to information stored on punched cards.

In early usage, people regarded the underlying hardware (rather than the contents) as a file. For example, the IBM 350 disk drives were called "disk files". In about 1961 the Burroughs MCP and the MIT Compatible Time-Sharing System introduced the concept of a "file system", which managed several virtual "files" on one storage device, giving the term its present-day meaning. Although the current term "register file" shows the early concept of files, it has largely disappeared.