Unit 1 - 2 Flashcards
What is primary storage?
ROM AS WELL
RAM - Part of the motherboard - Stores data, programs and instructions that are CURRENTLY IN USE - VOLATILE
What is the need for primary storage?
Gives processor fast access to data and instructions that primary memory holds
What is RAM?
Random access memory, can be read and written, holds data that is currently being used - VOLATILE
What is ROM?
Read only memory - NON VOLATILE - Also primary storage, can only be read, cannot be edited, ideal for storing data and instructions
What is the purpose of virtual memory?
Data is moved to virtual memory when RAM runs out of storage to store data - makes computer RUN SLOWER, processor has to wait for data to be swapped between virtual memory (hard disk) and RAM
What is secondary storage?
NON VOLATILE - LONG TERM STORAGE, used to keep data and programs indefinitely
What are the examples of secondary storage?
Magnetic storage - HARD DISK
Optical - DVD
Solid state drive (SSD) - USB,SSD (flash memory)
What is 4 bits known as?
A nibble
8 bits (2nibbles) is known as?
1 Byte
What is 1000 bytes?
1 kilobyte
What is 1000 kilobytes?
1 megabyte
What is 1000 megabytes?
1 gigabyte
What is 1000 gigabytes?
1 terabyte
What is 1000 terabytes?
1 petabyte
What are the 2 possible binary digits?
0 or 1
What is binary digit known as?
A bit
What is analogue data?
A real life signal that can vary in value (size)
Give 3 examples of analogue data?
Sound waves, pressure, temperature
Why do computer’s use binary?
They use digital electronics which can be only interpreted as on or off (0 or 1)
What does A = in hexadecimal?
10
What does F - in hexadecimal?
15
What are the 4 types of binary/denary conversions?
Binary Conversion (DENARY AS WELL)
Binary shifts
Binary addition
Hexadecimal conversion
Define character set?
Collection of characters used to represent text in a computer system which includes symbols and numbers which the computer will process and display
What is ASCII?
A character set of character codes was developed to solve compatibility issues. NOT POSSIBLE TO REPRESENT ALL CHARACTERS
What is unicode?
Uses 16 bits for each character and now has been expanded with other codes for 120000+ characters to try cover all symbols and characters
What is the use of unicode?
Universal for all computer devices webpage software, web browsers use this encoding system to display text and even emoji’s
Define pixel?
Described by binary numbers and are grouped to display pixelated imagery
Define metadata?
Width and height of the data about data
What are the bits per pixel?
More bits per pixel means higher definition and accuracy
What is colour depth?
Length of code that determines the number of different colours displayed
What is resolution?
Clarity of an image dependant on being displayed on a screen or paper (legibilty)
What can affect file size?
Colour depth
What is bit depth?
Number of bits to store each individual pixel
What is the affect of bit depth?
Larger bit depth allows image to use more colours
How do you calculate an image size?
Size = bit depth X number of pixels
How do you calculate the size of a sound file?
Size = bit depth X sample rate X duration of sound
Why is compression needed?
To make files smaller, usually in storage where there is limited capacity
What is LOSSY compression?
Technique that results always in a permanent loss of data from a file, when decompressed, data is recreated into the file, this data is never exact
What is lossless compression?
Technique used where no data is lost and when a file is decompressed the content and data is identical just as it was before being compressed
Give examples of where you would use 1. Lossy and 2. Lossless
- An image given it might lose slight colour depth and the shading will become more average.
- Sound files may result in ower frequency
- Text files, do not want to lose
- Spreadsheets, do not want to lose
