ICT - Unit 1 : Digital devices

Mainframe computers

used by large organizations for complex processing tasks such as statistical analysis and bulk data processing as they have huge processing power built to handle enormous amounts of data

-finance

-health

-government -etc

Microprocessors

small integrated circuits embedded into devices to help them perform calculations, excute instructions and control functions and are used to control washing machines, televisions and other household appliances (like home entertainment systems security alarm systems and central heating systems)

personal computers

common in homes and offices

-in form of desktops and laptops

desktops are more powerful than mobile computers and are upgradable to increase the performance

a laptop computer is designed for portability and convenience, typically having a built-in screen, keyboard, and battery.

they are less powerful due to power constraint due to size and they focus more on extending battery life

they are not easily upgradable and battery powered

-some laptops are used as desktop replacements

advantages and disadvantages of laptops

portable , flexible (access to internet and resources from anywhere) , multifunctional )

difficult to upgrade hardware, lower performance and requires frequent charging due to short battery life)

specialist phones

mobile phones that have specialist features to provide users with functions that meet particular user needs

senior phones - large buttons , simplified user interface , easy to read display , emergency buttons , hearing aid compatibility

children’s phones - brightly colored , parental control, limited app access

rugged phones - designed for tough environment , thick screens and withstands water submersion dust and extreme temps

smartphones

small computers with wifi and mobile phone connectivity to allow them to make phone calls and access the internet using a subscriber identity module (SIM)

SMS messaging - quick communication w messages stored

phone calls

Voice over internet protocol (voIP) - audio and visual communication via internet

accessing the internet

mobile payment

camera

tablet devices

bigger than smart phones but have similar features

• portable

• used for entertaintment

• more powerful than smart phones but not as powerful as laptops

• longer battery life depending on the usage

digital cameras and camcorders

use light sensors to capture images and pictures formed by light passing thru the devices lens

• lens

• image processor

• sensors

game consoles

designed to enable users to play video games on tv screens

• powerful processors and graphics

• online capability

• controllers

home entertaintment systems

hub for connecting audio and video devices

• connects tvs speakers and media players together

• provides immersive expierience

• processes audio and video signals

includes

• tvs

• smart tvs

• personal video recorders

• blue ray and dvd players

media players

provide video and audio content to a tv

• portable

• plays different media like blue ray and dvd

navigation aids

can calculate the best route between two or more locations and provide updates if route not followed accurately

uses GPS satellites to determine exact location of the device

multifunctional device

a device that can perform a range of different functions

combines functions that would usually be separate

• smartphones - communication , photography , streaming . web browsing

• printers - print , copy and scan

• smart tvs - watch tv connect to internet and stream

convergence

combination into one device of the features of multiple other devices

features of digital devices

• portability - how easy it is to carry around

• performance - processing power and memory (RAM)

• storage - how much data it can hold

• user interface - how the user interacts with the operating system

• connectivity - how can the device connect to other devices

• media support - what media formats the device can play

• energy consumption - how much energy does the device consume

• expansion capability - can more storage memory and other features be added

• security features - what features does it have to protect device and user data (software security used to prevent unauthorized access to data - passwords , PIN , biometric scanners ——- physical security - security locks)

user interface

how the user interacts with the operating system

• command line interface (CLI) - text base commands commonly used by advanced users

• graphical user interface (GUI) - uses visual elements such as WIMP (windows icons menus and pointers) , optimized for mouse and touch gesture (windows android mac os)

• Menu - successive menus with a single option at each stage performed w buttons or a keypad (ex. vending machines , chip and pin machines , entertainment streaming services )

• Natural language interface ( NLI) - uses spoken words to respond to spoken or textual inputs from a user (virtual assistants , search engines and smart home devices)

software

set of programs that control the hardware , cant be physically touched

• application software

• system software

application software

programs designed so users can carry out a particular task like writing letters

installed on top of the system software

• word processing - create and edit text documents

• spreadsheets- organise and analyze data in a grid format

• database management systems - stores retrieves and manages data in databases

• control/ measurements - uses sensors to measure and control a system

• video editing - create and modify video files

• graphics editing - create and modify image files

• audio editing - create and modify sound files

• computer aided design (CAD) - design and model objects in 2D or 3D

system software

carries out tasks for the computer

essential for the operation of a computer system

gives users a platform to run applications and carry out tasks

• comliers- translates programming language into machine code

• linkers combines object files into single executable program

• device drivers - control hardware components and peripherals

• operating systems - manages the computer’s resources and providing a user interface

• utilities - tools for maintaining and optimising the computers performance

utility software

designed to help maintain enhance and troubleshoot a computer system

interacts w the computers hardware (ex. secondary storage)

examples of utility softwares and their function

• defragmentation - groups fragmented files back together in order to improve access speed , its added in order and over time as files get deleted it leaves gaps that get filled and data becomes fragmented (CAN ONLY BE USED ON MAGNETIC STORAGE)

• compression - reduces the amount of secondary storage requrired by performing an algorithm on the original data (lossy compression removes data to reduce the size and cant be recreated , lossless compression uses mathematics to order data more efficiently so it can be recreated and data isnt lost)

• encryption - scrambling data using an algorithm from plain text into cipher text to make it unreadable to users without a master key

• task manager (troubleshoot/repair) - monitor system resources to help troubleshoot potential problems (services app history performance processes users start up apps)

operating system

software that allows users to control and manage the computers hardware

functions

• memory management -allocating RAM between diff programs open at the same time , copying data from secondary to primary storage , RAM allocated based on priority and fairness to make multitasking possible

• resource management- processor management by dividing time and allocating them to different programs. also manages the way input and output devices interact with the software. also files as theyre able to create organize and manipulate files

• security- allocate different access rights for diff users on the network as well as maintain settings for individual users(background icons colors) can provide software firewalls and keep a log of files created by users,

• print spooling- when printing is required a temporary holding area (queue) is made to increase efficiency

there are two types:

• single user operating system - for a single general user, with no option to customize the interface for different users (ex used in household appliances.

• network operating software (NOS) - access to network storage and shared resources as server is sent requests when users log in , and each user account is kept separate so people dont access eachothers files

software applications

office productivity software

• word processing , desktop publishing , spread sheet and database

web authoring

image editing

• graphics editor , image editor

sound editing

presentation software

control software

project management software

3 types of software licenses

free software

• user has the right to study modify copy or distribute the program

open source software

• make source code available to users so they can modify/edit the software code and distribute

• allow collaboration , less buggy , free, strong social support

• relies on support from others, you need expert knowledge to edit code , doesnt recieve regular updates, open to exploitation by adding malicous code

proprietary software

• software marketed and sold for a fee made by professional companies that have more regular updates

• created to proffesional standard

• cost can be significant , limited expansion , relies on one company

• may not fully meet user needs

communication software

provides remote access to systems and to exchange files and messages

• web browsers - software used to access and display info on the internet - function : to access html/ webpages

• email - method of exchanging messages and files over the internet used for personal communication , professional correspondence and marketing

• social media - platform for users to connect and share content - users can create profiles and share text images videos and links with privacy settings

• SMS/MMS - short message service and multimedia service is a way to connect using a mobile phone network where no internet is required

• instant messaging- requires internet connection and allows multimedia communication - extra features like offline and online status , see when users are typing and location data.

software updates

how to update - download file off internet then install

• to fix bugs or software vulnerabilities

• increase compatibility

• improve performance

• introduce new features

• improve usability

risks of updating your software

• incompatibility

• work flow distruption - new features may need time to adjust to slowing down productivity

• updates issues leading to data loss

risks of not updating

• often has flaws which gives opportunities to hackers

• outdated softwares can lead to data breaches and installation of malware

input devices

hardware components that allow users to input data or commands into the system

• keyboard

• mouse

• joystick

• graphics tablet

• scanner

• digital camera

• webcam

• microphone

• resistive touch

• capacitive touch

• omr

• ocr

• barcode scanner

• biometric scanner

• magnetic stripe reader

• chip and PIN reader

• RFID reader

• analogue sensors

output device

recieves info and presents it

• CRT monitor

• LCD monitor

• LED monitor

• laser printer

• inkjet printer

• dot matrix printer

• 3d printer

• plotters

• multimedia projector

• speakers

• actuators

secondary storage device

hardware that reads from and writes to diff storage media thats non volatile

• magnetic - uses magnets to store binary 0s and 1s , it has HIGH STORAGE CAPACITY , LOW COST , MODERATE SPEED , but ITS NOT DURABLE DUE TO MOVING PARTS , NOT PORTABLE AS ITS HEAVY , NOT RELIABLE DUE TO MECHANIC FAILURE, AND NOISY

• Solid state storage - uses electronic circuits to store binary 0s and 1s - MEDIUM CAPACITY , VERYYY FAST , DURABLE AS NO MOVING PARTS , AND PORTABLE AS SMALL , BUT VERY COSTLY , AND LESS RELIABLE DUE TO LIMITED READ WRITE CYCLES

• Optical storage - uses lasers to create pits and lands to store binary 0s and 1s - VERY CHEAP , DURABLE ( NO MOVING PARTS ) , PORTABLE SMALL NO MOVING PARTS , SILENT , BUT VERYYY LOW CAPACITY , VERYY SLOW AND PRONE TO SCRATCHES SO UNRELIABLE.

Capacity of storage

Byte - 8 bits

KiB- 1024

MiB - 1024²

GiB - 1024³

TiB -1024^4

storage media

physical media that holds non volatile data

• magnetic storage media - HARD DISK - made up of platters that spin on a central spindle , read/write head moves on an arm across the platter

• the amount of time it takes to read/write data is influenced by - revolutions per minute (how fast platter spins) and how fast the head moves across the platter

• optical storage device - OPTICAL MEDIA - all recordable some can be rewritten , CDs DVDs and Blu-ray

• Solid state storage media - FLASH MEDIA - more reliable than hard disk due to no moving parts and very fast read write speed

• MAGNETIC TAPE - old tech now used to store alot of data for backup , very slow

RAM

random access memory

volatile - data is lost when power is off

stores instructions currently in use

very fast , faster than secondary storage

much larger capacity than ROM

RAM capacity can be increased to improve performance

ROM

read only memory

primary storage

holds boot up instructions that computer needs to start up

small memory chip in the motherboard

faster than secondary storage but slower than RAM

non volatile

read only

smaller capacity

capacity cant be increased

some types can be changed

• EPROM - erasable programmable read only memory

• EEPROM - electronically erasable programmable read only memory

flash memory

• Flash memory is a type of EEPROM (Electronically Erasable Programmable Read Only Memory)

• Non-volatile

• Fast access times

• Low power consumption

• Used in solid state drives, USB drives and SD memory cards

Central processing unt (CPU)

purpose to execute instructions

achieves this by completing processor cycles

processor cycle stages

• fetch stage - instruction or data must be fetched from the computer's memory (RAM)

• decode stage-CPU needs to work out what is required from the instruction 

• execute stage - CPU will carry out the instruction that was fetched

how is the speed of the processor measured

• by its clock speed

• clock speed measured in Hertz ( Hz )

• number of processor cycles in 1 second

number of cores

• works like its its own CPU

• multiple cores means multiple separate processing units

• multi core processors run more powerful programs with greater ease

devices and peripherals to meet specific needs

devices

• desktops - high performance tasks

• laptops - portable

• tablets- touch control , good for reading and simple applications

• smartphones - portable , communicaton

peripherals

• keyboard and mouse

• monitors

• printers and scanners

• external storage

peripherals that aid accessibility

• ergonomic keyboard - designed to reduce strain by preventing repetitive stress injuries (RSI)

• screen readers - assist visually impaired

• braille displays

• braille keyboard

• brain printers

• haptic feedback/vibration devices - visual

• reading pen - those with dyslexia

software to meet specific needs

productivity

• word processors

• spreadsheets

• presentation tools

specialized software

• CAD program - for design and engineering

• Graphic design tools - visual content

• database management systems

accessibility softwares

• screen readers

• voice recognition software

• magnification tools

settings and ICT Systems to meet specific needs

system configuration

• display settings : brightness font size

• audio settings

• accessibility features : screen magnifiers and voice commands

hardware and software

• network settings

• user permissions

• security protocols

accessibility hardware and software solutions

hardware

• adjustable monitor stands

• alternative input devices : reading pen , braille keyboards

software

• screen readers

• voice to text applications

• customizable keyboard shortcuts