Data Representation / Computer Systems Revision Flashcards
What are the prefixes for measuring storage?
Kilobyte, megabyte, gigabyte, terabyte
Construct a binary conversion table.
What is a pixel?
A picture element; the smallest part of an image.
What does ‘resolution’ mean?
The number of pixels forming an image or screen. Can be quoted in dimension (width x height) or total number.
What is the difference between lossy and lossless compression?
Lossy compression removes some data, while lossless keeps all data.
What is a bitmap?
A grid of coloured (can be just black and white) pixels which form an image.
How do you convert binary into hexadecimal?
Convert each whole nibble of binary into decimal, then convert to hexadecimal using 0 to 9, A, B, C, D, E, F.
What is run-length encoding?
A lossless method for compressing data where the number of each repeating characters are stored.
What are the three key components of a computer?
Processor, memory and storage.
What does the processor do?
Executes (runs) the instructions which programs are made up of.
What does the computer’s memory do?
Holds programs and data, which are running.
What are storage devices used for?
To store programs and data, even when the computer is switched off.
How does a magnetic hard drive work?
Uses magnetism (north/south) to store binary data on a spinning disk (platter).
How does a solid state drive work?
Traps electricity to store programs, files and data in binary form.
How does an optical disk work?
Uses laser to store programs, files and data in binary form.
