Summary of Grade 11 Computers, Part of Your Life - Computer Applications Technology
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Course
Computer Applications Technology
Institution
11th Grade
Book
Computers, Part of Your Life
My Grade 11 CAT Notes provide comprehensive coverage of all the material in the Study Opportunities CAT textbook while condensing the material into a much more manageable format. These notes include everything needed to pass with a distinction.
CAT Theory
Information Communication Technology
Allows us to:
Work from any computer
Identify and adapt to trends
Communicate effectively with employees and customers
Perform repetitive actions with consistent quality
Requires upgrading of skills, hardware & software. Few skilled ICT workers take jobs of many.
The Computer
Information processing cycle: Input, process, output, stored, communicated
Different factors make a computer powerful
o Speed & performance of CPU
o Type & amount of storage
o Size of memory
o Type of graphics card
Can get desktop replacement laptops (as powerful, cost more)
Smartphone -> tablet -> laptop/notebook -> desktops -> servers
Portable computers
Tasks such as entertainment, web, communication, social networking demand portability
Better for work (can work from home)
Laptop: portable computer which uses miniaturised parts that have low power consumption
(work on batter power)
Tablet: portable computer with touch screen / pen-sensitive screen. Have long battery life &
wireless / cellular data connectivity
Smartphones rely on touch screen for keyboard (have OS, data modem, GPS, cameras, Wi-Fi)
Power settings
OS provides power schemes/settings to control power management
o Specify sleep after amount of time
o Brightness of screen
o Balance between power consumption and performance
Hybrid laptops/tablets
Laptop with touchscreen and 360˚ hinge – rotate screen or remove
More powerful than tablets & run desktop OS
Weigh more, shorter battery life, no built-in cellular communications
Servers and clients
Servers: computers that provide services and resources to other computers (clients) that are
linked in the network (provide internet access, store files)
Network consists of 1 or more servers and many clients
Server is powerful – clients don’t have to be as powerful
Dedicated devices: perform 1 specific task (not a computer) e.g. ATM, GPS
Computers: multipurpose devices – can load apps which perform wide variety of tasks
Protecting your information
Should backup data
Encrypt sensitive data / backup in secure off-site location
Portable devices can easily be stolen (some organisations prevent their use)
Hardware theft and protections:
o Serial number should be recorded
o Mark components with ultraviolet pen for identification
o Install hidden security software
o Use cable locks to anchor equipment
o Use lockable cabinets
o Use motion sensors to detect when computer is moved
Uninterruptible Power Supply (UPS)
o UPS protects a computer against power surges/spikes or power outages
o Connected to mains (charge battery) and provide power to computers connected
when mains power fails (allows you to save work and shut down)
Input
Provides running software with instructions or data that must be processed (may be used or stored)
PDA – personal digital assistant
Image capture
Picture data is important – image quality becomes important
Digital Cameras
Variety of sizes & prices: smartphone, digital (compact) cameras, DSLR (digital single-lens
reflex)
Point-and-shoot means lens cannot be changed – compact for quick use
DSLR is professional – change lens & more control over technical settings
Advantages:
o Take thousands of photos (depending on memory card)
o See images immediately & delete / transfer to edit on computer
o Can record video
Disadvantages (now fallen away):
o Cost, quality, poor low light
Specification Meaning
Lenses Larger lenses capture more light, improving
image quality & detail
Sensor Size Large sensors capture light more effectively
(better for low light) & take photos more
accurately in various light conditions
Larger sensors capture better quality (even if
same megapixels)
Optical / Optical zoom uses lenses to get closer to object
Digital Zoom (better quality)
Digital zoom makes picture larger to get closes
– gets pixelated
Resolution Total number of pixels that makes up the
picture (usually 10-30MP) – one of several
factors that determine quality
ISO rating How sensitive the camera is to light
Scanners
Scanner: input device that scan images to a computer – barcodes, documents, 3D objects
Convert images into format that can be stored digitally
All have similar hardware specs – different settings in software affect quality
o Resolution (measured in dots per inch – dpi) – greater dpi, more pixels & better
quality, also larger file size
o Colour depths refer to number of colours that can be represented by a pixel – 24bit
usually enough as more colours results in bigger file
Advantages:
o Large documents consisting of many pages can be collected into a single file
o Electronic copies do not take up office space
o Can scan documents containing text & use OCR (Optical Character Recognition) to
edit the document
o Barcode scanners used in libraries & Point of Sale for speeding up checkout
o QR codes let people quickly connect to a website
Disadvantages:
o Takes a lot of time, depending on scanner
o Quality of image depends on quality of hard copy
Biometric Input
Biometric Input Scanners capture unique biological feature of a person – used scanners to
read & recognise their features for identification
Advantages:
o More secure than passwords (usually badly created)
o Tied to single person – difficult to defeat (can’t be copied)
Disadvantages:
o Expensive to implement & maintain
o Need additional hardware & software
Input at ATMs
Automatic Teller Machine gets input (PIN, language choice) through keyboard/buttons as
well as other sources:
o Card reader: user inserts bank card into slot to scan data on magnetic strip
o Modem / network connection: ATM has to communicate with bank – needs input
from computer at bank to determine if PIN is correct, balance is high enough to
withdraw
o Touch screen: replace keypad/menu buttons
o Money counter: sensor counts number of notes given out – tells when ATM runs out
of denomination or counted enough notes
o Money deposit slot: draw opened & envelope is place in, then moves it to container
before being periodically collected & account is credited. Input provided by sensor
detecting when draw is closed
Criminals use card skimmers – read data on magnetic strip & store
Thieves download data wirelessly – can copy card
Use hidden camera to record pin
Advantages:
o Allows banking transactions at any time
o Banks allow you to use facilities at any ATM (not limited to your bank’s ATMs)
Disadvantages:
o Dangerous – probably have cash & attract criminals
o Can install skimmer & camera to steal money
Input into POS systems
Barcodes & Radio Frequency Identification tags are used to:
o Recognise item / product
Barcodes need barcode scanners to scan barcode
RFID tags store data on tag which can be detected wirelessly
Provide fast, reliable means of identifying objects – lead to:
o Faster processing at payment points
o Better stock control
Scanners (optical for barcodes, radio for RFID) used to record stock bought
Data stored in database & price allocated to items
Cashier uses a scanner to record all items being bought
Advantages:
o Faster than typing in prices – less queues
o Prices updated & entered with greater accuracy
o Business records how many items are sold & how much stock left – know which
items are selling well & when more stock is needed
Disadvantages:
o Difficult to function when system is offline
o Expensive equipment & software required
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