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validation check
contrôle m de validité

Validity check. Verifying that the data is meaningful due to the possibility that the original data collector may have made a mistake. Validity checks do not eliminate errors completely, but they make it difficult for incorrect data to enter the computer.

There are several methods for verifying coded numbers:

- Checksum digit: A coded number that is added and divided by a predetermined coefficient. If the number is divided exactly, i.e. without a remainder, it is considered valid and meaningful.

- Weighted check digit: An additional stage of multiplying each digit by a coefficient is introduced. It is known that hundreds of years may pass before a coded number passes incorrectly in this way.

- Range checks: Verifying that the data is within acceptable limits.

For example:

IF age % < 1 OR age % > 1 THEN PRINT "Data error".

- Checks on number tables: Using hash (batch totals. All the data in the table are combined to give a meaningless total. This total is verified at the preparation and entry stage.

- Checks on strings (words, names, lists, etc.): Using look-up tables that represent files of data such as names, addresses, and lists, stored on a disk. The computer compares each entry with the data table and matches it with it.

All these validity checks can be programmed into the computer so that it can perform the check automatically.

valve
tube m

A valve. An electronic device invented in 1900 that contains a path inside a glass bulb (like a regular light bulb). Valves were used in radios, televisions, and computers. The first computer contained about 18,000 valves. The valve has been replaced today by the transistor and other semiconductor devices.


variable
variable f

A variable. A part of a store or memory used in programming to store data provided by the user. Data can be entered either by a touchpad or written into the program. A variable is called this name because one can change or modify the data in it. Each variable has a name and a type that distinguishes it. For example:

- Common types of variables in BASIC:

Integer (number) variable = % name
Text or text variable = $ name

Real number variable (accepts decimal parts) = name .

- Using variables:

answer % = first % + second %
PRINT carname $

This displays the contents of $ carname .

If the data is in the form of a string (attribute table), several locations can be used to store the data.

VDU

Abbreviation for visual display unit .

verification
vérification f

Verify. Check that something has been printed and sent accurately. One of the tasks of the entrants is to type what is in front of them accurately, but mistakes may occur, for example: Some of the common mistakes in entering 041772 could be:

1 - Copying error (typing a number incorrectly):
041792.

2 - Swapping places (two numbers swapping places): 042771.

3 - Double exchange of places (two pairs of numbers switch places: 014277

4 - Random errors (complete chaos).

Verification ensures that such errors do not enter because errors can be very serious.

Using paper media (tape or punched cards), a second copy is prepared. If there are any discrepancies with the first copy, the reader stops the contact plate. The entry operator then decides which of the two copies is correct.

In magnetic media (tape or disks), a second copy is also prepared and placed on a tape or disk unit and the two copies are compared.

In the case of transmitted data, the parity bit is checked, which is an additional bit added in the preparation phase for each word. The check shows whether the data has been corrupted during transmission.

Very large-scale integration (VLSI) intégration ƒ à très grande échelle

Very large-scale integration. As in large-scale integration Large-scale integration (LSI) is also a measure of the number of logic gates on a single chip. Between 1960 and 1970, designers produced more and more gates on a single chip, and the number has been doubling almost every year since 1959. First came small-scale integration (SSI) with up to 20 logic gates, then medium-scale integration (MSI) with 20 to 100 gates. By 1969, large-scale integration (LSI) had emerged with 100 to 5,000 logic gates, and since 1975, we have had very large-scale integration with more than 5,000 gates on a chip about half a square centimeter in size.