Computer Systems Flashcards
Hardware
Physical components of a computer that can be touched or seen
Software
Programs and instructions that tell the hardware what to do, including operating systems, applications and utilities
System software
Controls and manages hardware and provides a platform for running application software
Application software
Designed to perform specific tasks for the user
Describe the roles of the operating system
Multitasking- allows computers to run many applications at a time
User interface- what we use to interact with the computer
File management- function that the operating system uses to organise and see files stored on a computer system
Memory management- the managing of the computers primary memory
Von Neumann architecture
A computer architecture that stores program instructions and data in the same memory, allowing the CPU to fetch, decode, execute and store instructions sequentially
Roles within CPU
ALU - performs arithmetic and logic operations
CONTROL UNIT - coordinates activities of the CPU and controls flow of data within the CPU and to/from other devices
CLOCK- synchronises operations of the CPU
REGISTER- temporarily stores data and instructions
BUS- Transfers data between CPU components and other hardware devices
Factors affecting CPU performance
Clock speed
Number of cores
Cache size
Instruction set architecture
Fetch execute cycle
The process by which the CPU fetches instructions from memory, decides them, executes them,and then stored the results back in memory
Types of memory
ROM- non volatile memory containing unchangeable data
RAM- provides temporary storage for data and program instructions that can be read and written
Cache- high speed memory used to store frequently accessed data and instructions for faster access
Register- fast temporary storage locations within the CPU
Difference between RAM + ROM
RAM is volatile and can be both read and written whilst ROM is non volatile and can only be read from
RAM is used for temporary storage during program execution while ROM stores permanent system instructions
Main memory vs secondary storage
Main memory (RAM) is volatile and provides fast access to data and instructions for the CPU
Secondary storage (hard drives) is non volatile and provides long term storage for data and programs
Need for secondary storage?
Needed to store data and programs permanently since main memory loses its contents once power is turned off
Types of secondary storage
Optical- uses lasers to read and write data
Magnetic- stores data on magnetic surfaces, such as hard disk drives
Solid state- uses semiconductor based memory such as solid state drives and USB
Cloud storage
Refers to storing data on remote servers accessed over the internet rather than on local storage devices
