Computer works with binary number system that is consist of only two digits zero and one. Inside the computer binary number is represented by an electrical pulse. One means a pulse of electricity and zero means no pulse. All the data enters into the computers first converts into the binary number system. One digit in binary number system is called bit and combination of eight bits is called byte. A byte is the basic unit that is used to represent the alphabetic, numeric and alphanumeric data.
Data is the combination of characters, numbers and symbols collected fro a specific purpose.
Data is divided into three types; alphabetic data, numeric data and alphanumeric data.
Numeric data consist of ten digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, two signs + and – and decimal point . There are different types of number system that are used to represent numeric data.
These number systems are decimal number system, binary number system, octal number system and hexadecimal number system.
Alphabetic data is used to represent 26 alphabetic. It consist of capital letters from A to Z, small letters from a to z and blank space. Alphabetic data is also called non numeric data.
Alphanumeric data used to represent alphabetic data, numeric data, special character and symbols.
Any type of data is represented in computer as binaries. The binaries are the 1 or 0. Actually the 1 mean ON and 0 mean OFF. This combination can represent any type of data.
For example, we want input the letter A.This letter will be converted to its binary codes by using ASCII (or any other which is used by computer) codes.The code for A letter is 65.The 65will be converted to its binary equivalent which is 01000001.By using same logic any type of data is represented in computer.
Following are the types of data.
Numerical data: the numerical data consists of numbers only (decimal or float) e.g. 28774,
Alphabetical data: The alphabetical data consists of letters and symbols e.g. car, bridge, man.
Alphanumerical data: This type of data is the combination of alphabetical data and numerical
data e.g. Abc23, 34 New street.
Apart from these types of data the data can be in the form Audio visual data, physical data, Musical data. These types of data is provided by using special kind of hardware. The use of these data types is not limited and the examples of such data can be seen easily.
Computer is a system to manipulate data. Monitor, where we see data, is not the place to store them (though one of the police team had ceased the monitor to investigate a case of data theft!). It is the secondary storage devices (hard disk, floppy disk, CD, DVD, etc.) where the data are stored. Whatever we write through the keyboard or try to push through the various input devices, the corresponding input devices convert them first into digital signals to produce 0 or 1 (bits). These continuous streams of bits are then stored or represented signifying the non-availability or availability of the voltage. To avoid further ambiguity in retrieval, these bits are stored and accessed in a group, say 8 bits together. The group of 8 bits is called byte and thus the higher units of bit calculation are the KB (1 KB = 1024 bytes), MB (1 MB = 1024 KB), GB (1 GB = 1024 MB), etc.
There exist several kinds of data such as Textual, Numerical, Alphanumerical, logical, Pictorial or Audiovisual. Each type of data has some pre-defined way of representation and other behaviour inside the computer. The textual data are the alphabetic character set of any language whereas the digits constitute the numeric part of the data. The mixture of alphabetic and numeric data together form the alphanumeric character sets. The logical data are those that help to analyse the comparison concept. Pictures and sounds create the pictorial and audiovisual data for the computer.