Digital Data

“What is data?”

Data is raw facts and figures which are meaningless as they have not been processed. Information is data in a context that has meaning added, so data that has been processed.

“What are the units of storage?”

Bits,nibbles,bytes,kilobytes,megabytes,gigabytes and terabytes are all used to describe DISK SPACE , STORAGE or THE CAPACITY OF A SYSTEM’S MEMORY.

Bit

A ‘bit’ is short for BINARY DIGIT. It is the smallest unit of data that can be stored by a computer.

“Each bit is…?”

Represented as a binary number , either 1 or 0.

Nibble

A NIBBLE is the term given to a group of 4 bits. Therefore , TWO NIBBLES make a BYTE.

Byte

A BYTE CONTAINS 8 BITS. A single keyboard character (letter,digit or special character) that you type, takes up ONE byte of storage.

Kilobyte

A kilobyte is 1024 BYTES. This is enough to store 1024 characters on screen.

Megabyte

A megabyte is 1024 KILOBYTES.

Megabyte examples?

• A megabyte would be able to store around 300 typed essays.

• A 10 slide presentation with an image on each slide and a theme could be 2-3 megabytes.

• An MP3 song could be 3-5 MB in size.

Gigabyte

A Gigabyte is around 1024 megabytes.

Megabyte examples?

• 1 GB could hold a classroom wide shelf of books.

• A DVD film would hold 4-8GB.

• Hard disks are measured in GB typically 160GB.

Terabyte

A terabyte is 1024 gigabytes. High end hard disks useful for network backups.

Numeric data (Integer and real)

A numeric data type contains numbers. An INTEGER is a whole number, positive or negative. A random example is 24,1000,-12,87,-60. A REAL numeric data type is a number that contains a decimal point. It can ALSO be positive or negative. Another random example is 1.34,8.5,-4.53,1.0,0.90

Date/Time

This is a data that allows a date or time to be stored. A date and time can be in many different formats.

Examples for dates and time:

18,12/2016, 18-12-16, 18th December 2016.

Time: 9am, 21:12:05, 23:00.

Character:

A letter, number and symbol are all known as a character. Programming languages use the data type character or ‘char’. It takes up ONE BYTE of storage.

String

This is Lao sometimes known as ‘text’ or ‘alphanumeric’. A string allows letters, numbers, punctuation marks and symbols to be entered.