Knowledge Information and Data

Definitions:

As an example, consider a stock control system that is being used to keep up-to-date data about levels of stock as items are sold. When an item is sold, the stock number that is transmitted to the computer is an item of data. Taken on its own the number has no meaning. As a result of the transaction a number in the stock file representing the current stock level is decreased. This number is another item of data. The stock file itself is made up of data. It is a series of numbers representing data about stock items. In simple terms data is what is entered into and stored by a computer. The data stored in a computer system will be processed to provide information. Information is processed data. It is what the computer outputs. An example would be a list of all items of stock where the number in stock is less than the minimum stock level. The data that makes up the stock file has been processed to obtain this information. The processing that has been carried out in this case is a selective search of the data stored in the file. Knowledge is what you get when you interpret information. We are nearly out of a particular item or this item is selling really well are examples of knowledge that can be gained by interpreting the information obtained by processing the data in the stock file.

Representation of data

Data is information removed from its context. It relates to facts, events and transactions and it is made up of a set of raw values. These raw values could be numbers, letters, dates, true/false values or anything else, such as symbols. Since computers can process only numerical data, other types of data must be coded as numbers before they are input to a computer system. For example, characters have been traditionally coded using the internationally agreed ASCII (American Standard Code for Information Interchange) codes where A is represented by the number 65, B by the number 66 and so on. ASCII has the limitation that it can only represent 127 characters. Many modern systems use Unicode as a method for representing characters. This allows over 32000 different characters to be represented and is used by the later versions of Microsoft Windows and many Unix systems. It includes the ASCII codes to maintain compatibility and is itself a subset of a larger representation which can allow over 4,000,000,000 different characters.

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