Computer systems Flashcards
what is von neumann architecture
the stored program computer involves storing both programs and the data that they use in memory.
what is the purpose of the cpu?
central processing unit
continuously reads and executes instructions stored in memory by carrying out the fetch-execute cycle.
what is the fetch-execute cycle?
cpu instructions are fetched from memory
decoded by the cu to find out what to do
and then executed.
every operation is carried out within the fetch-execute cycle regulated by a cycle of the cpu clock
name all the components of the cpu
alu
cu
clock
registers
bus
what does alu do and stand for?
arithmetic logic unit, and carries out mathematical and logical operations (boolean) and binary shifts
what does cu do and stand for?
control unit which coordinates all of the cpu’s actions.
sends and receives control signals to fetch and write data.
what does the clock do?
regulates the speed and timing of all signals and computer functions
what are registers?
smaller and faster than cache memory
built into the cpu chip to temporarily store memory addresses, instructions / data.
used in fetch-execute cycle.
function of the bus?
collection of wires used to transfer data and instructions from one component to another.
what are the types of memory?
ram
the main memory and is the largest
cache
relatively small and fast memory that can transfer data faster than ram (more expensive)
registers
special purpose memory located within cpu to execute instructions
Define hardware
Physical components of the computer
Define software
The programs that run are run on the computer hardware
What is the relationship between hardware and software
Both need each other to work.
Hardware takes user input, software runs the program then hardware outputs the program result
Define system software
System software manages the computer system and acts as a platform to run application software.
Give an example of system software
- ios
- Android
- Windows
Define application software
Application software is software that performs tasks on the computer
Give an example of application software
- Google docs
- Spotify
- Youtube
Define opperating sytems
A collection of programing that manages and controls the computer
What do opperating systems do
Opperating sytems manage :
- The processor
- memory
- input/output of devices
- applications
- security.
Define Utility programs
Software designed to help maintain and optimise a computer system
What are the different types of memory within the computer
- RAM
- ROM
- Cache
- Register
What is volatile data
Data that will not be saved if the computer is switched off
(RAM)
What is non volatile data
Data that will be kept if the power is turned off
What is RAM
Random Access Memory
- Volatile
- Can be stored and accesses from any location in the memory
What is RAMs purpose
Holds programs and data that are currently in use.
RAM can be changed at anytime by overwriting it with other data
(e.g. games, open docuements)
What is ROM
Read Only Memory
- Non-volatile
- Cannot be changed- only read from
What is ROMs purpose
To store data and instructions that are needed for the computer to run.
(e.g firmware)
What is cache
RAM located in the CPU that that stores commenly used instructions
Why is Cache important
Makes executing commen instructions much faster as they are already in the CPU
What is register memory
Small amounts of high-speed memory contained within the CPU
What is the purpose of register memory
They store important information needed in processing
(e.g. the address of the next instruction to be executed, the results of calculations)
Define main memory
The part of the computer that stores data that can be accsessed by the CPU (not cache or registers)
It can be volatile or non volatile
What types of storage are main memory
ROM - non volatlie
RAM - volatile
Why is main memory used
Data can be read or written quickly as it is close to the CPU
Define secondry storage
Secondary storage is any non-volatile storage mechanism not directly accessible by the CPU.
What are the 3 types of secondry storage
solid state storage
optical storage
magnetic storage
Why is secondry storage used
It stores programs and data that needs to be stored long term.
