Digital data

Digital Data

• Representing Data
• Data consists of raw facts and figures which have not been processed and therefore do not have a meaning or a context. Data doe not have any meaning unless it has been processed. E.g. 431 is just a sequence of digits.
• Information is data that has been processed and given a meaning or context. E.g.. 431 is a patients id number
• Order of Bytes
• Bit - A binary digit known as a bit is either a 0 or a 1. it is the smallest unit of storage
• Nibble - a group of 4 bits put together, or half a byte.
• Byte - consists of 8 bits.
• Kilobyte - 1024 Bytes
• Megabyte - 1024 Kilobytes
• Gigabyte - 1024 Megabytes
• Terabyte - 1024 Gigabytes

Data Types

• Numeric data - Numeric data simply means Numbers. Numbers come in a variety of different types. Integer or Real
• Integer- An Integer is a whole number. It has no decimals and no fractional parts. An Integer can be both positive or negative. e.g. 123, 1. -89, 10
• Real number - Any number that you can place on a number line is a real number. Real numbers include whole numbers, numbers with factional and decimal parts and real numbers can be both positive and negative e.g. 0.36454, -1.54 , 45, -98
• Date and Time - Date and time data is usually formatted in a specific way. The format depends upon the setup of the computer, the software in use and the preferences of the user.
• Characters - characters can be letters digits, spaces or punctuation marks. e.g. ! d $ /
• currency - currency refers to real number that are formatted in a specific way. Usually currency is shown with a currency symbol e.g. £3.00 £488 $3 $26
• Alphanumeric data - refers to data made up or letters and numbers .Usually symbols and spaces are also allowed
• Boolean(logical) data - Boolean data is sometimes called "logical" data(or in some software yes/no data) Boolean data can only have two values e.g. True/False or Yes/No
• String - textual data that is in the form of a list of characters like words , this data will vary in length and is made up of character data. e.g. hello world

Bitmap and vector based graphics.

• Bitmap graphics
• - Bitmap graphics store details about every individual element(pixel) of the image
• -Storing every pixel means the file size of a bit map image can be very large
• - A bit map image can also be compressed, which reduces the file size.
• Vector based graphics