ICT Digital Devices

secondary storage

it is non volatile, meaning it will keep data if there is no power. this may be external or internal

storage methods

magentic, optical and solid state

magnetic storage

makes use of a magnetisable coating. Magnetised dots are made on the surface of the material.

magnetic storage advantages

cheap, large storage capacities and fast write speed

magnetic storage disadvantages

lots of mechanical parts and not very durable

optical storage

makes use of a laser to shine and reflect light to read the data stored eg, CD and DVDs used to store songs and videos

optical storage advantages

cheap, portable and takes up little space

optical storage disadvantages

less storage, easily damaged and slow write speeds

solid state drives SSD

solid state disks use non volatile flash memory to store information used in higher end computers and laptops

solid state drives advantages

highly durable , no moving parts and very fat read/write speeds

solid state drives disadvantages

more expensive similar storage to magnetic disks

how a flash memory works

Large electric current used to force electrons through a barrier and trap them on the other side .They remain on the other side until ‘flashed’ with a new current, eg usb sticks and cameras

flash memory advantages

low cost, portable and no moving parts

What is RAM ( random access memory)

the part of the computer that temporarily stores the instructions that the computer is running, and the data it is processing. RAM is a volatile storage device as it loses data if the power is turned off

What is ROM ( read only memory)

ROM contains the BIOS (Basic Input Output System) . ROM stores data permanently held in the primary storage it is non volatile as the data is not lost when the power is off. eg stores BIOS and initial program the computer runs

processors

A processor is made up of one or more central processing units (CPUs), they carry out software instructions . Each CPU is referred to as a core.

clock speed

describes the time per second the processor can carry out one or more instructions

mainframe computer

are high performing computers with large amount of memory, storage and hundreds of processors that run billions of instructions simultaneously

microprocessor

the of job of the microprocessor is to run the instructions of your computer program eg mobile phones, and washing machines

server

is a computer program or device that manages and provides a service to another computer program and its user

desktop computers

a general purpose computer that is designed to carry out many different tasks eg video editing,gaming and web browsing

mobile computers

are easy to move around and are portable eg smartphone,iPad and laptop

digital cameras and camcorders

use light sensors to capture images formed by light passing through the device lens. The quality depends on the lens eg capturing memories and advertising

navigation aids

calculate the best route between two locations, they work using the internet. smartphones are replacing in car navigation eg waze and google maps

multifuntional device

used to perform multiple different tasks. eg smartphone can used to text,calls,photos etc. eg printer , smart phone and gaming consoles

convergence

blurs the distinction between different types of devices eg smartphone and tablet

system software

is used manage hardware and running application includes operating system and utility software,.

application software

used to carry out a specific task such as word processing and spreadsheet.

managing memory

the os that decides which program and data are moved from secondary to RAM

multi tasking

processors appear to be running in parallel but they are just being swapped in and out of RAM very quickly

security

stops unauthorized people from accessing data and protects memory from other processes.

print spooling

temporally storing print jobs inside the memory until the printer is ready to handle them

utility software

is a type of system that helps run and manage the computer run its everyday tasks

backup

creates a copy of files and programs

compression

reduces the size of files

software updates

updates are done to fix bugs and add to new features etc

software licenses

the set of rules that tell you how can use a specific piece of software eg open source and closed source