Please enable JavaScript.
Coggle requires JavaScript to display documents.
Memory and Storage - Coggle Diagram
Memory and Storage
Memory
RAM (Random Access Memory)
Stores programs and data in use
ROM (Read Only Memory)
Used in embedded systems
Washing machines
Microwaves
Sat Navs
Cannot be written to
Virtual Memory
Part of Secondary Storage
Used when RAM full and another program opened
Allows more programs to run than RAM has space for
Slower than RAM
Images
Composed of pixels
Colour depth
Stored in binary
Sound
Stored in binary
Frequency measured in Hz
Quality dependant on samples per second
Secondary Storage
Storage Types
Hard Drive (HDD)
Not portable
Fairly cheap cost per Gb
Large stoage capacity
Becomes fragmented over time so m,ay require defragmentation
Solid State Drive (SSD)
USB Pen Drive
Portable
Can be password protected
Durable
Expensive cost per Gb
Relatively small storage capacity
Mobile Phone storage
CD
Cheap
Can get scratched
Portable
Retains data when loses power
Units and Binary Numbers
Units
Processor speed - GHz
Frquency - Hz
RAM - Gb
Storage
Bit
Byte (8 bits)
Kilobyte (1,000 bytes)
Megabyte (1,000 Kb)
Gigabyte (1,000 Mb)
Terabyte (1,000 Gb)
Petabyte (1,000 Tb)
Nibble (4 bits)
Binary Numbers
Combination of 0s and 1s
Raw machine code
Represent on/off for millions of switches
Binary Arithmetic and Hexadecimal
Binary Arithmetic
0 + 0 = 0
1 + 0 = 1
1 + 1 = 0 carry 1
1 + 1 + 1 = 1 carry 1
Hexadecimal
Characters 0-9 and A-F
Used for colour codes
Can easily be converted to/from binary using nibbles
Characters
Converted to binary
ASCII (American Standard Code for Information Interchange)
UNICODE
Input using keyboard peripheral
Compression
Reducing file size
Lossy
Data is lost permanantly and cannot be recovered
Images
Songs/ Audio Files
Lossless
Data is retained and can be recovered
Text documents
Executable (.exe) files