Every piece of information that is entered into a computer's memory is encoded as some unique combination of the digits 0 and 1. These 0 and 1s are called Bits. A bit is an electronic device that is either On or Off, representing the 0 or 1.
Byte: A byte is the amount of computer memory that can store one character of data. A character is an alphabet, a digit or a symbol. It is made of 8 bits and as such a particular combination of ON or OFF determines the character held in that byte.
Kilo Byte: Even the smallest of computers has a memory of thousands of bytes. So there is a larger unit of memory called Kilo Byte (KB or K) 1K = 1000 bytes approximately (actually 210 = 1024 bytes).
Megabyte: This is 1024 x 1024 = 1048576 or say 1 million bytes.
Data Item, Group Item: Computers operate on data to communicate results. Data must be arranged in pre-determined ways to satisfy the numeric, alphabetic or alphanumeric forms demanded by a programe. they are organized into characters, field, record and file.
Characters: It is the building brick of information. It is a letter, a digit or symbol. All information is made up of characters.
Field: Each piece of information formed with the use of characters is called a field of information.
Record: A collection of related characters grouped into Fields becomes a record. the computer compares and performs the tasks in a predetermined order. Steps are then taken on the basis of the result.
File: A collection of records make a File.
Next: Character Coding