Representation of data concepts and data processing

Representation of data concepts and data processing
Definition of Data
Data is distinct pieces of information, usually formatted in a special way. All software is divided into two
general categories: data and programs. Programs are collections of instructions for manipulating data.
Data can exist in a variety of forms -- as numbers or text on pieces of paper, as bits and bytes stored in
electronic memory, or as facts stored in a person's mind.
Strictly speaking, data is the plural of datum, a single piece of information. In practice, however, people

use
data as both the singular and plural form of the word.
 
Basic data types
In programming, classification of a particular type of information. It is easy for humans to distinguish

between
different types of data. We can usually tell at a glance whether a number is a percentage, a time, or an

amount
of money. We do this through special symbols -- %, :, and $ -- that indicate the data's type. Similarly, a
computer uses special internal codes to keep track of the different types of data it processes.
Most programming languages require the programmer to declare the data type of every data object, and

most
database systems require the user to specify the type of each data field. The available data types vary from
one programming language to another, and from one database application to another, but the following

usually
exist in one form or another:

integer : In more common parlance, whole number; a number that has no fractional part.
floating-point : A number with a decimal point. For example, 3 is an integer, but 3.5 is a floating-point
number.
character (text ): Readable text
 
Storage of data as files
Computer data storage, often called storage or memory, is a technology consisting of computer
components and recording media used to retain digital data. It is a core function and fundamental
component of computers. The central processing unit (CPU) of a computer is what manipulates data
by performing computations.
A modern digital computer represents data using the binary numeral system. Text, numbers, pictures,
audio, and nearly any other form of information can be converted into a string of bits, or binary digits,
each of which has a value of 1 or 0. The most common unit of storage is the byte, equal to 8 bits.