Digital Devices in IT Systems

Digital Devices in IT Systems

Digital Devices

  • Digital devices form part or all of IT systems, including:
    • Multifunctional devices
    • Personal computers
    • Mobile devices
    • Servers
    • Entertainment systems
    • Digital cameras (still, video)
    • Navigation systems
    • Data capture and collection systems
    • Communication devices and systems

Smartphone as a Digital Device

  • Smartphones are widely used digital devices with various functions:
    • Making calls, sending text messages
    • Clock, alarms, timer
    • Application software (Apps)
      • Email
      • Web browser
      • Internet banking
      • Social networking and messaging
      • Games
      • Video calling

Multifunctional Devices

  • A multifunctional device performs many different functions.
  • Examples:
    • School photocopiers (photocopying, printing, scanning, sending faxes)
    • In-car entertainment systems
    • Smart TVs
    • Mobile phones, tablets
    • Laptops or PCs
  • A device is considered digital if it is controlled by a microprocessor, which can be programmed.
  • Examples of single-function digital devices:
    • Microwave oven
    • Digital radio
    • Alarm clock
    • Washing machine

Types of Digital Devices (Classified by Usage)

  • Multifunctional devices
  • Mobile devices
  • Entertainment systems
  • Digital cameras (still, video)
  • Navigation systems

Personal Computers

  • Small, general-purpose computers designed for use by one person at a time.
  • Popular types:
    • Desktop
    • Laptop
    • PC
    • Mac

Desktops vs. Laptops

Desktop Advantages:

  • Screen at eye level (better posture)
  • Easy to upgrade
  • Generally faster processor and graphics processor for the price
  • Easier to expand, modify, and upgrade
  • Harder to steal

Laptop Advantages:

  • Lighter (more portable)
  • Integrated camera, speaker, and microphone
  • Batteries can take over if the power supply fails
  • Fewer compatibility issues with integrated devices
  • More power-efficient

PC Sales Trends

  • PC sales rose from 71 million in 1996 to 365 million in 2011.
  • Sales decreased to 259 million in 2018.
  • Decline in PC sales is possibly due to the rise of smartphones and tablets.

Mobile Devices

  • Smartphones and tablets have transformed how people use computers.

Advantages of Mobile Devices

  • Very light and easily stored (pocket, bag, or handbag)
  • Use solid-state storage (fast and durable)
  • Very fast to log in from standby
  • Internet connection allows for better use of cloud applications

Business Use of Mobile Devices

  • Email and other work functions can be carried out remotely.
  • Apps can extend functionality (e.g., taxi service, receipt imaging).

Entertainment Systems

  • Include:
    • TVs
    • Stereos, sound systems
    • Radios
    • Games systems
    • Home cinema

Digital vs. Smart TVs

Digital TV:

  • Better picture quality (HD, UHD/4K)
  • Better sound quality (clearer, surround sound)
  • More channels

Smart TV:

  • Recording programs
  • Streaming TV

Games Consoles

  • The global games market was worth over £100 billion in 2018.
  • Dedicated to computer games and entertainment.
  • Customized controllers.
  • Motion sensors for hands-free gaming.

Servers

  • A server is a hardware unit that provides a service to other programs.
  • Typically fast and powerful to serve many devices and users.
  • A web server serves web pages to user’s web browsers.

Types of Servers

  • Mail server (for email)
  • Web server (for web pages)
  • Database server (for websites, social networks)
  • File server (for files on a school network)
  • Print server (for printing files)
  • Game server (for running multiplayer video games)

Digital Cameras

  • Digital cameras increased in popularity between 1999 and 2010, peaking at over 120 million units per year.
  • Sales have since fallen.

Huawei P30 Pro (2019) Camera Features:

  • 40 Megapixel wide-angle quad camera (rear)
  • 5x optical zoom
  • Low-light photography
  • Flash
  • High Dynamic Range (HDR) video
  • Allow users to:
    • Plan routes
    • Receive audio and visual instructions
    • Reroute drivers around traffic problems

GPS

  • The Global Positioning System (GPS) has 31 satellites orbiting the earth.
  • Each satellite transmits a unique time signal.
  • A position is calculated by the time taken for the signal to reach the devices.
  • At least three satellites are needed to calculate a position.

What3words

  • Divides the world into a grid of 3m x 3m squares.
  • Allows a unique location to be given anywhere in the world with just three easy-to-remember words.
  • Uses a mobile app and GPS to find any location with three words.

Data Capture Devices

  • Used to collect data electronically to be processed.
  • Examples:
    • GPS receiver
    • Credit/debit card reader
    • Automatic number plate recognition (ANPR) camera
    • Barcode readers
    • Biometric capture devices (fingerprint reader, iris reader)
    • Near Field Communication (NFC) devices (mobile/contactless payments, connecting electronic devices)
    • RFID (Radio Frequency Identification) (contactless payment cards)

Mobile Payments

  • In 2018, contactless payments overtook chip and pin with over 50% of card payments.
  • Use an RFID chip.
  • Can be used for payments up to £30.
  • Fast payment process.
  • Less secure (normally don’t require a PIN).

Communication Devices

  • Computers, mobile phones, and tablets can be used for communication.
  • Connected together in networks using:
    • Wi-Fi
    • Network cable (copper and fiber optic)
    • Routers

Communication Technologies

  • Wireless: Wireless Access Point (WAP), Bluetooth
  • Mobile phone: 2G, 3G, HSDPA, LTE, 4G, 5G
  • Fibre: Fibre to the cabinet (FTTC), fibre to the premises (FTTP)
  • Hardware: Network Interface Card (NIC), switch, router

Digital Devices in Various Tasks

  • Walking: Mobile phone, CCTV
  • Driving a car: Satnav, in-car entertainment system, Bluetooth, mobile phone, ANPR, CCTV, cruise control, auto/self parking, Engine Management System (EMS)
  • Traveling on a train: Mobile phone, laptop, LED passenger information system/departure board
  • Traveling on a plane: In-flight entertainment, tablet, mobile, autopilot

The Function and Use of Digital Devices

Learning Technology

  • Technology helps users learn and solve problems.
  • Resources:
    • Video sites (YouTube)
    • Social media
    • Search engines (Google)
    • Specialist forums

Education and Training Technologies

  • Interactive whiteboards
  • Laptops and personal computers
  • Internet for encyclopedias and research

Educational Technology Examples

  • Educational apps (research, repetitive exercises)
  • Learning Platforms:
    • Virtual Learning Environments (VLEs)
    • Massive Open Online Courses (MOOCs)
    • Commercial learning platforms (Coursera, Udemy, Udacity)
  • Video learning
  • Audio learning (especially for languages)

Case Study: edX

  • MOOC created in 2012 by MIT and Harvard University.
  • Over 14 million students.
  • More than 1800 courses.
  • Free study from top professors.
  • Online problem discussion.
  • Answers automatically marked.

Personal Use of Digital Devices

  • Smartphones (communication, shopping, payments, video, music)
  • Smart home devices (Amazon Echo, Google Home) (control TVs, lighting)
  • Smartwatches (fitness monitoring)
  • Fitness trackers (Fitbit) (monitor food intake, activities, weight)
  • Smart sensors (tennis racket analysis)
  • Smart mat (yoga pose correction)
  • Satnav devices (walkers, cyclists) (accurate maps, rugged)

Social Use of Digital Devices

  • Social networks (Facebook, Twitter) (faster communication)
  • Social groups (shared interests)
  • Messaging apps (text, images, video sharing)

Case Study: WhatsApp

  • Messaging app owned by Facebook.
  • Communication between users is encrypted.
  • Text messages to individuals or groups.
  • Voice calls using VoIP (Voice over Internet Protocol).
  • Over 1.5 billion users.

Retail Use of Digital Devices

  • Barcodes and barcode scanners
  • Card payments and mobile payments
  • RFID tags on expensive products
  • Self-service checkouts
  • CCTV
  • Loyalty cards

Store Closures

  • In 2018, over 2,500 UK stores closed.
  • Companies in administration: HMV, House of Fraser, Poundworld, Bench, Toys ‘R’ Us, Maplin.
  • Over 46,000 jobs affected.
  • Internet is a major factor.
  • Benefits for consumers over traditional stores.

Case Study: Boxed

  • E-commerce start-up selling bulk goods.
  • Fully automated warehouse.
  • Two miles of conveyor belts.
  • Autonomous cart collects goods.
  • One-hour staff training.

Organizational Use of Digital Devices

  • Financial accounts software
  • Electronically recorded bills and receipts
  • Reports written in word processors
  • Organization of schedules, to-do lists, and project management

Business Communication

  • Sharing information to customers:
    • Advertisements and product information
    • Websites (purchasing decisions, customer support)
    • Marketing through social media
  • Sharing information inside companies:
    • Email and file servers
    • Telephones and VoIP
    • Cloud computing software (collaboration)

Creative Tasks Using Digital Devices

  • Video editing and film production
  • Image and photo editing
  • Animation
  • Music production
  • Computer game production
  • 3D modelling
  • Programming of games engines and apps
  • Desktop design
  • Web design

Film and TV Technologies

  • Video cameras (4k & 8k with solid state storage)
  • 2D and 3D Animation, Special effects (SFX/FX)
  • Greenscreen/bluescreen (chroma key)
  • Digital editing
  • Drones

Case study: Motion Capture

  • Motion capture was used in the creation of Gollum in Lord of the Rings.
  • Heavily used in the film and games industries.
  • Records actor against a green screen.
  • Special dots or sensors are located all over the actor to record movement.
  • Cameras may be located on their head.
  • Other animals or creatures can be mapped onto the actor as used in recent Planet of the Apes films

Methods of Protecting Data

Antivirus Software

  • Protects against malware.
  • Types of malware: virus, trojan, worm, ransomware
  • Antivirus software companies: Avast, Avira, Bitdefender, ESET, Kaspersky, McAfee, Sophos, Symantec/Norton

Protecting Against Malware

  • Update computer operating systems and software, and apply patches.
  • Malware attacks vulnerabilities fixed by software companies.
  • Obsolete systems like Windows XP should not be used.

Case Study: iOS 12

  • Released in 2018 with security updates.
  • Risks of not updating:
    • Bluetooth communications could be intercepted.
    • Apps could read restricted memory.
    • Auto-filled data could be stolen from Safari.

How Antivirus Software Works

  • Runs in the background.
  • Maintains a virus definition database (regularly updated).
  • Checks executable files against known viruses and malware.
  • Uses heuristic analysis to detect suspicious behavior.
  • Quarantines or deletes infected files.

Detecting a Virus

  • Virus definition is stored in a database.
  • Files are scanned to see if they contain virus definitions.

Real-Time and Full Scans

  • Real-time scan: checks each file before it is saved, copied, opened, or run.
  • Full scan: checks every file on a computer system.

Quarantine and Removal

  • Infected files are moved to quarantine (cannot be opened or run).
  • Malware removal is often difficult as it infects many files and avoids detection.
  • Antivirus software removes or cleans a system from the virus.

Implications of Using Antivirus Software

  • Full scans take a long time and slow down the computer.
  • Real-time scanning may slow down browsing, downloading, installing software,and copying files.

Protecting Against Hackers

  • Finding out a password is often the first step in illegal access.
  • Protection:
    • Create passwords that are hard to guess.
    • Use different passwords for different accounts.
    • Change your password regularly.

Validating a New Password

  • Length check (10-15 characters).
  • Format check (mixture of numbers, lower and uppercase characters, and symbols).

Verification of a New Password

  • User inputs the password a second time, and the software compares the two entries.

Other Verification Methods

  • Online services may have verification procedures if you attempt to sign in while you are away from home (e.g., phone number, recovery email address, security questions, sending a security code to a mobile phone).

Security Question

  • Some websites ask for selected letters from a password or security question answer.
  • This prevents hackers from finding the whole password

Foiling Spyware

  • Some organizations ask for letters to be selected rather than typed in.
  • This technique makes it harder for spyware such as keyloggers to record the keystrokes pressed

Captcha

  • Asks a user to enter the text or numbers in an image.
  • It is hard for computers to read these, so only humans will be able to enter the numbers.
  • Helps to prevent brute-force attempts at cracking a password

Common Passwords

  • Names of pets
  • Significant dates (e.g., birthdate)
  • Other family members’ names
  • Place of birth
  • Favorite holiday
  • Favorite football team

Password Manager

  • It can be either installed on a device or use an online system.
  • All passwords are then stored within a highly encrypted database.
  • One password is then used to unlock access to the password manager
Advantages:
  • Only one password needs to be remembered
  • Very long and complicated passwords can be created
  • Passwords will be truly random
  • Log in screens can be automatically filled in saving users time
Disadvantages
  • If someone steals the main password (e.g. with a keylogger) they have access to every password
  • Solution: Password managers will often have two-factor authentication and only certain devices that are allowed access

Threats From Digital Devices

  • Many devices come with a default password or PIN to gain access
  • The default is frequently 0000, 1234 or admin
  • Research has shown that 20% of all passwords and PINs have never been changed
  • Always change the default

Keeping Systems and Data Secure

  • The vast majority of computers and devices are connected to the Internet
  • This leaves them vulnerable to attack from other, untrustworthy computers and devices

Firewalls

  • A system designed to prevent unauthorized access to or from a private network.
  • It forms a barrier between a trusted internal network and an untrusted external network such as the Internet.
  • It can be implemented as hardware, software, or a combination of both

Ports

  • Data from the Internet goes to a specific port based on the service it is for. Ports on a firewall are like doors on a house
  • These ports can be blocked by the firewall.

A Two-Way Firewall

  • A one-way firewall protects a computer system from incoming threats
  • A two-way firewall will also prevent malware or undesired applications from connecting to the Internet
  • Packets of information coming into the network can be checked to see if they are legitimate. This is known as stateful packet inspection (SPI)
  • Rules can be created to allow access to only certain services or websites

Firewall In Home Routers

  • A home wireless router usually contains an effective built-in, hardware firewall.
  • This firewall can prevent attacks from the Internet.
  • It can also prevent an infected computer from attacking other computers by preventing the malicious software from sending information out of the home network

Limitations of a Firewall

  • They cannot protect against an insider attack
  • They cannot protect against malware introduced via an external drive
  • If they are not properly configured they can give a false impression that the network is safe
  • If a company’s firewall is incorrectly set up it may result in the network slowing down
  • Firewalls may block some games and should be carefully configured rather than being turned off

Peripheral Devices and Media

Input and Output Devices

  • Input:
    • Digital camera, webcam, scanner, microphone,graphics tablet, MIDI keyboard, trackball, game controllers,bar code readers
  • Output:
    • Printers, projector, 2nd display/monitor,headphones, speakers
  • Input and output:
    • Touch screen

Case Study: Waymo

  • Waymo is a self-driving car created by Google
  • The car started as the Google Self-Driving Car project in 2009
  • The new 2018 car is built by Jaguar
  • The car will be used as a taxi service with the technology also being used in self- driving trucks
  • Waymo has driven over 6 million miles on roads and simulated driving more than 5 billion miles
  • The car started taking public passengers in Phoenix, USA in 2018
Input Devices:
  • Lidar (light/laser radar)
  • Radar
  • High-resolution cameras
Output Devices:
  • Motor
  • Indicator lights
  • Brakes
  • Steering actuator

Case Study: Amazon Echo

  • The Amazon Echo is a type of smart speaker
  • It makes use of the voice-controlled assistant called Alexa
  • The device was first released in 2014
  • Being controlled by voice, the device has very few input/output devices
Input devices:
  • Microphones x7
  • On/off button, action buttons
  • Volume control wheel
Output devices:
  • LEDs
  • Speakers x2 (one woofer and one tweeter)

Case Study: VoIP Phone

  • Many modern businesses now make use of Voice over Internet Protocol (VoIP) phones
  • These connect to an Internet router anywhere in the world
Features include:
  • Displays incoming numbers
  • Handset, headset and speakerphone
  • Buttons light up if extensions are in use or voicemail is received

Storage Devices

  • Storage drives and media have different characteristics. Typically we are interested in:
    • Capacity – how much storage space there is
    • Speed – how quickly data is transferred
    • Cost – how expensive is the device
    • Durability
    • Reliability
    • Portability

Magnetic Hard Disks

  • A magnetic platter contains data
  • A read-write head reads and writes data to the disk
Advantages:
  • Very large capacities
  • Fast to access data
Disadvantages:
  • Fairly large so less portable
  • Not very durable if knocked or dropped

Solid State Hard Disks

  • Solid-state devices store data using flash memory chips
Capacity
  • Similar to magnetic disks, but more costly per Gigabyte
Speed
  • Typically faster to transfer data. Faster to access is there is no wait for the drive head to move
Durability
  • These drives are more durable and are more likely to cope with vibrations or being dropped
Reliability
  • These drives are more reliable as they have no moving parts
Portability
  • These drives are more portable as they are lighter and can be significantly smaller

Solid State Media

  • Solid-state storage is used in:
    • USB removable media
    • SD cards
    • Internal storage of tablets, smartphones and some laptops

Optical Media

  • In optical media, the data is stored on a disk
  • A laser follows a spiral track running from the inside to the outside
  • Compact Discs (CDs) typically have a capacity of 700 MB
  • DVDs capacity is 5GB
  • Blu-ray discs store 25GB or 50GB
  • Some disks store up to 300GB
  • The track is 5km long for a CD and 27km long for a Blu-ray
Capacity
  • Typical capacity of disks is lower than solid state or magnetic disks, especially CDs and DVDs
Speed
  • Blu-ray disks are fast to access data such as video, but slower if the drive head needs to move constantly
Cost
  • They are very cheap to share information compared to solid state
Durability and Reliability
  • Scratches will lead to data loss, but Blu-ray disks are more durable and reliable
Portability
  • Disks are portable if stored correctly. However, they are not small enough to be used in phones and tablets

Magnetic Tape

  • Data is stored on a magnetic tape
  • Accessing individual files is very slow due to winding through the tape
  • Magnetic tape is often used to store backups
  • Storing 15TB on a tape in 2019 costs around £50
  • Tape backups are very reliable
  • Tapes are small and portable

Accessibility Devices

  • There are many disabilities that make computers and electronic devices difficult to use including:
    • Blindness and poor eyesight
    • Arthritis or repetitive strain injury (RSI)
    • Inability to move hands, arms, or legs

Ergonomic Keyboard

  • These keyboards often split the keys into a V shape
  • The keys are positioned at an angle so that there is less stress on each hand
  • A wrist support will help keep wrists higher reducing strain
  • Ergonomic keyboards are useful in preventing repetitive strain injury (RSI)

Speech Recognition

  • For people who have difficulties typing, speech recognition will allow them to enter text without using their fingers
  • Dictation software is now accurate enough for people to use on a daily basis
  • Most operating systems and many other devices can now be operated by voice

Sight Problems

  • Braille is added to keypads and buttons to help people who are blind
  • This allows them to feel the text displayed
  • Text to speech software can read text aloud using a speaker
  • This is known as speech synthesis

Magnifiers

  • Many operating systems and devices allow people to magnify areas of the screen
  • This allows anything on the screen, including text and images, to be increased in size
  • The magnifier can be set to follow the mouse or follow the cursor as the user types

Software to Help With Sight Problems

  • Narrator – this speaks aloud each character pressed and where on the screen the mouse has selected
  • High contrast – Changes colors so that text contrasts well against its background
  • Color filters – Applies a filter such as grey or a specific set of colors to the whole screen
  • Cursor and pointer size – can be increased to make these easier to see

Manual Data Processing

  • Manual data processing requires manually entering information into the computer system. It can include:
    • Entering sales orders over the phone
    • Entering prices at a checkout
    • Adding customer information to a database from a paper form
    • Marking a test or exam paper and then entering the results into a computer

Automatic Data Processing

  • Automatic data processing is where data is input and processed by the computer. Examples include:
    • Car park tickets and free space
    • Gas and electricity smart meters
    • Electronic seismometers
    • Race timing with RFID
    • Weather stations

Benefits of Automation

  • Car parks do not need to employ staff. A car park can make sure it has free spaces before allowing more cars in
  • Smart meters can automatically update electricity and gas companies with meter readings so that bills are accurate
  • Automatic seismometers can detect earthquakes instantly and help give warnings for tsunami that may be minutes away
  • Race timing with RFID makes times more accurate and can measure many runners at once
  • Automated weather stations can give live data about the weather and don’t need a person to check each of the readings. Weather prediction can be based on more accurate data

Case Study: Blood pressure

  • Blood pressure usually takes a nurse or doctor a few minutes to read it
  • A blood pressure monitor can allow a user to take their own blood pressure
  • Multiple readings can be taken over an extended period
  • They can reduce increases in blood pressure caused by anxiety of doctors or nurses

Operating Systems

Mobile Operating Systems

  • Android popularity
    • Free operating system
    • Customizable by phone manufacturer

Features

  • Operating system manages phone hardware and software
  • Connect to phone and Wi-Fi and Bluetooth networks
  • Security (passwords/fingerprints)
  • User input (virtual keyboards)
  • User interface (icons/swiping)

Operating Systems Manage:

  • Hardware devices
  • Software
  • Users

Operating Systems

  • Windows, Android, iOS, Mac OS, Linux

Application Software

  • Office software, games, video editing, desktop publishing, web browsers and many more

Hardware Components

  • Displays, keyboards, mice, storage/hard drives, graphics cards, sound cards, CPUs microphones, buttons and many more

Case study: iOS 1

  • Launched by Apple in 2007 as iPhone OS
  • There was no App store or iTunes app on the first release
  • It came with the following apps: mail, photos, calendar, Safari, YouTube, maps, clock and camera
  • Only one app could be run at a time

Single-User, Single-Task

  • iPhone 1 ran a single-task operating system
  • If you tried to run another app, the first app would pause allowing the second one to run
  • A device that only allows one user to use it, or has no log in, uses a single-user operating system. For example:
    • Satnav
    • Car entertainment systems
    • Televisions
    • Digital camera

Single-User, Multi-Tasking

  • A multi-tasking operating system allows the user to open many applications at the same time
  • A user may be able to listen to music whilst also browsing the web and writing a report in a word processor
  • A single application may have a number of tasks which it needs to run
  • Windows, Mac OS, iOS and Android are all examples of multi- tasking operating systems
  • Two apps or items of software can be run at the same time
  • These operating systems only allow one user to be logged in at a time
  • They are therefore known as single-user, multi-tasking operating systems
  • In these operating systems, a user or program will not know if something that needs processing will be done by a certain time
How Does Multi-Tasking Work?
  • Many computers only have one CPU but are able to multi-task and run many programs at the same time
  • Running programs are stored in Random Access Memory (RAM)
  • Each program has an amount of time using the CPU
  • When it is time for the next program to run, the current values stored on the CPU are moved to RAM
  • The next program can now be run again
  • By switching very quickly, users can run several programs at the same time

Real-Time Operating Systems

  • A real-time operating system will need to have completed executing certain instructions by a specific time
  • Failure to do so may be fatal
  • Uses include:
    • Flight-control systems for planes or spacecraft
    • Train management systems

Real-Time OS Uses:

  • Engine management systems for:
    • engines, brake lights and anti-lock braking system (ABS)
  • Air traffic control systems
  • Light railways and autonomous trams
  • Air conditioning systems

Multi-User Operating Systems

  • Many users can access the same computer from their own terminals
  • Each user is given processor time
  • A problem with one user doesn’t affect other users
  • For instance, a number of website programmers could all access the same web server to fix a problem with a website
  • Multi-user operating systems are often used to access super-computers

Network Management

  • Operating systems need to manage how computers connect to a network
  • They present users with available networks
  • Airplane modes turn off all network connections
  • The operating system will re-send packets of data that have not been received correctly

Security - Users

  • Users are often restricted from accessing certain files or programs
  • User security aims to prevent one user from damaging another user’s files or programs that they are running

Security

  • Password protection
    • Each user will have their own password to use a computer
    • These should be strong passwords to prevent users guessing them or a computer performing a brute-force attack (guessing every possible combination of letters) on the password
  • File access protections
    • File servers can restrict files to individual users or groups of users
    • They can give users any combination of read, write or execute (run) access

Device Drivers

  • Device drivers are needed by the operating system to manage devices such as keyboards and printers
  • The driver sends signals, known as interrupts, to the hardware
  • It translates these, so software can understand them
  • When a signal is received from a device, it will be put in a queue until the operating system is ready to deal with it
  • Every time you touch a smartphone screen or move a mouse, an interrupt is sent to the operating system

Memory Management

  • The operating system manages the Random Access Memory (RAM)
  • RAM is used to store programs that are running such as apps, browsers, software and the operating system itself
  • When a program or app is opened or run, the operating system will allocate it an amount of RAM to use to store instructions and data
  • The CPU will read instructions and data from RAM
  • The operating system prevents one program from being able to read the data of another program

What Happens If The Operating System Runs Out Of Ram

  • RAM is full the operating system can no longer load programs or data
  • Modern operating systems use an area of the hard drive as virtual memory
  • Unused programs and data are moved to virtual memory to free up RAM
  • New programs and data can then be loaded into RAM

Virtual Memory

  • Using virtual memory slows the computer down
  • The operating system spends time moving programs and data from RAM to the hard drive
  • It then spends more time moving them from the hard drive to RAM
  • Hard drives are much slower than RAM, especially if they use a disk and constantly need to move a drive head – known as disk