Hardware-Computer science wjec gcse yr11

Components of a cpu

ALU, CU, Registers and Cache memory

Control unit usage

Sends and receives signals from all parts of the computer, ensures all processes are in the right time and order

ALU usage

Simple calculations and comparisons on high level language

Register usage

Fast access temporary data store for data accessed so often

Cache memory usage

Fast memory access for the CPU of data often used

3 busses

Address bus, Control bus, Data bus

Address bus use

Storage address of data being saved and loaded always travels across the address bus

Data bus use

The path the data travels along

Control bus use

Sends control signals to different parts of the computer

Von Neuman architype

Von Neumann architecture is a computer design where program instructions and data are stored in the same memory and processed by the CPU using the fetch-decode-execute cycle.

FDE cycle explained

The Program Counter (PC) stores the address of the next instruction. This address is copied to the Memory Address Register (MAR). The instruction stored at that memory location is fetched from RAM and placed into the Current Instruction Register (CIR). The Control Unit (CU) decodes the instruction and carries out the appropriate action.

What is clock speed

FDE cycles in a second measured in hertz

What is overclocking

Purposefully increasing the clock speed further than its original design

Drawbacks of overclocking

More heat produced, More energy required and more heat can damage the CPU and cause lower lifespan

What is underclocking and why would it be used

Lowering the clock speed than its original design, this is used to extend the life cycle of the device

What is Dual core and how does it affect performance

Dual core is having two CPUs and are able to split tasks up making more efficient with parallelable code, however if the result of instruction 1 is needed before 2 can go it is not more efficient

RISC meaning and usage

Reduced instruction set computer and it can process relatively simple instructions

Benefits of RISC

Simple instructions are done quickly and have less power consumption therefore less heat generated

CISC meaning and usage

Complex instruction set computer and its usage is being able to process a large number of complex instructions with only a few instructions

Benefits of CISC And drawbacks

Doesn’t have to break complex instructions but more power consumption and therefore more heat

Definition for an input device

Allows data to be entered into a computer system

Definition for an output device

Outputs made by the computer for example sound or on screen data

What is RAM

Temporary volatile storage of the currently running program

What is Read only memory ROM

Used for the Permanent storage of data and cannot be changed (Non-volatile)

What is BIOS

Basic input output system a low level program that handles input and output operations

What is Flash memory

Used for permanent storage of data however memory can be changed (Non-volatile)

What is cache memory

Volatile very fast changeable data of frequently used data

What is secondary storage and what does it hold

Data is written from memory to secondary storage when data is no longer being used for retrieval at a later time and it takes longer to access this data

What are frequently used backing storage media

Flash drive, External hard drive, CD/DVD, Magnetic tape

Flash drive information

Small files from work to home, 2gb-64gb, Good durable, portable, Good speed

External hard drive information

Backing up a home computer system, 500mb-4TB, Not durable, Portable, Good speed

CD/DVD/Blu-ray information

Storing multimedia files, 650mb (CD), 9GB (DVD), 50GB (Blu-ray), Good durability, Portable, Decent speed

Magnetic tape information

Backing large commercial servers on multiple tapes, 200GB-400GB, Decent durability, Portable, Slow

Optical storage information

Use lasers and if light is projected back it counts as 1 and if no light it counts as a 0, lasers are used to read and write information to a disk

Magnetic storage information

Used in hard disks and tapes, stored in a magnetic medium which can be a disk or tape by writing using a write head, data can then be read by the read head

Solid state storage information

Does not have any moving parts such as a read head in magnetic storage, low power consumption and high speed

Storage in the cloud information

A contemporary data storage facility on third party servers

Advantages for storage in the cloud

Maintenance tasks, backups and data replication, when buying a new device it is the responsibility of the cloud storage service provider

Disadvantages of the cloud

Internet connection is required to access the data, might be held somewhere with lack of adequate data protection legislation

Motherboard

Main circuit of the computer

GPU

Produces graphic images

Integrated GPU

Uses the computers RAM, it uses less power and produces less heat, perfect for general graphics processing

Dedicated GPU

Dedicated cards to provide the best visual experience, they use more power and require a good cooling system

Sound cards

Enable the computer to output sound through speakers, to record sound from microphone and manipulate sound stored on a disk, convert analogue input signals into digital data and reverse for output

What are embedded systems

A combination of software and hardware to perform a specific task, meant to be small to have a low cost, they are often reactive and have little hardware and the instructions are stored in ROM or flash memory with no peripherals