Unit 3: Understanding ICT Systems in Everyday Life Flashcards
Give examples of Input Devices? (9)
Keyboard, mouse, tracker pad, joystick, touch screen, microphone, scanner, digital camera + graphics digitiser.
Give examples of Output Devices? (6)
Visual Display Unit (VDU), Impact Printer, Laser Printer, Inkjet Printer, Plotter + Speaker.
Talk about:
Keyboards
Uses standard layout (QWERTY) Depends on human for input speed. Prone to human error. Used to enter text into computer. Some are designed for certain applications (EPOS + ATM) Fewer keys + emphasis on numeric keys.
What are concept keyboards?
Have keys with pictures/words that can be programmed to carry out certain instructions.
Talk about:
Tracker Pads
Known as touch sensitive pad.
Used as alternative to mouse on laptop.
Ideal for portable device as fine for confined space.
Movement on pad controls cursor, allowing user to select options from menus, select icons + position cursor.
Talk about:
Mouse
Referred to as ‘pointing device’, easy to use + inexpensive, designed to fit under hand, can contain 2 or 3 buttons for selection, slower than using ‘hot keys’, some use mouse ball + built-in movement, others use infared or wireless.
Talk about:
Joystick
Control object on screen by manoeuvring small lever in diff directions, senses movements converted to co-ordinates, has pre-programmed buttons to allow actions to be carried out + used to play computer games.
Talk about:
Touch Screen
Reacts to human touch, minimal user training, no add hardware, more expensive than LCD, used in banks, tourist offices, museums + supermarkets, used in hand-held consoles, PDAs + mobile telephones.
How does a touch screen work?
When user’s finger touches screen, vertical + horizontal light beams are sensed + converted into a co-ordinate. To perform ‘drag and drop’ operations, drag finger across the screen.
Talk about:
Microphones
Input sound/human voice into computer system, used in voice-recognition applications, natural communication form for humans, background noise can interfere, can record music + store in digital format.
Spoken word can be converted to text/computer can interpret spoken commands. Voice recognition useful for those with less mobility.
Talk about:
Scanner
Converts hard copy of pics/text into digital image. Beams of light passed over image which is recognised as series of dots on page.
Once scanned, can be saved + edited, if text scanned can be recognised by word processor using OCR then can be edited + saved, quality measured in dpi. Cheap scanners up to 2400 x 4800 dpi up to A4.
Talk about:
Digital Camera
Stores pics on memory card, small LCD screen attached to view pics, can be downloaded to computer by USB cable/wireless connection.
Can capture short vid clips that last couple mins.
How much does a typical memory card store?
4 GB, around 1000 pics in medium resolution.
Talk about:
Graphics Digitiser
Flat electronic sensitive surface that captures image drawn with stylus pen, allows user to record hand-drawn image in computer system + image drawn can be imported to graphics package for further editing.
Talk about:
Visual Display Unit (VDU)
Displays info/output from computer on screen. Made up of pixels, cost of monitor increases as size + resolution get bigger, LCD screen is lighter + smaller than typical desktop CRT screen, LCD require less power, some have inbuilt speakers + microphones + Modern VDUs have inbuilt filtering system to reduce eyestrain.
What is a pixel?
Smallest area on screen that can be edited. Pic is made up of pixels.
What is screen resolution?
Measure of the quality of an image on screen. More pixels, higher resolution.
Talk about:
Impact Printer
Print head made up of pins in rows + columns (matrix). Print head strikes ink ribbon leaving impression on page, characters formed as series of dots. More pins, better quality. Useful for carbon copies (invoices), prints in 1 colour, costs less than to print multiple copies (carbon copies), low quality, noisy.
Talk about:
Laser Printer
Non-impact printer, uses toner, some are 3in1 for scanner, photocopier + fax, usually have own memory here pages stored before printing, black+white/colour, suitable for high vol printing, good quality + high speed.
Talk about:
Inkjet Printers
Non-impact, black+coloured cartridges, ink heated + sprayed through nozzles/jets in print head, black+white/colour, print pics/low vol printing, high quality print, slower.
Talk about:
Plotters
Some use electronically controlled pens, others penless (raster) plotters, high quality, accurate + detailed diagrams, used by architects, surveyors, pattern makers + engineers, variety of paper size (A0), draws diff characters of diff sizes + fonts to add to drawings.
Talk about:
Speakers
Small internal speakers standard in computers, provides sound output through sound card, output music + spoken word, useful for visually impaired users + draws attention to input error.
How is memory measured on a computer?
What is the smallest unit of storage?
Bits + bytes 1 bit (binary digit) 1 or 0
1 byte = x bits 1 kilobyte (KB) = x bytes 1 megabyte (MB) = x kilobytes 1 gigabyte (GB) = x megabytes 1 terabyte (TB) = x gigabytes
8 bits 1024 bytes 1024 kilobytes 1024 megabytes 1024 gigabytes
What are the different types of data storage devices? (4)
Magnetic disks, magnetic tapes, optical devices + USB flash drives.
Talk about;
Hard Disks
Main storage device of computer system, number of rigid disks on top of each other with 2 surfaces consisting of tracks + sectors, read/write head for each surface, faster than CD drive, in sealed unit to protect from damage, internal hard disks used to permanently store operating system, app software + user data. External portable with high storage, attached using USB cable + suitable for little backup data.
Give examples of optical disks? (6)
CDs, CD-ROMs, CD-Rs, CD-RWs, DVDs, Blu-Ray disks.
What is the capacity of a CD?
What is the capacity of a DVD?
In terms of read/write, talk about DVDs?
What is the capacity of Blu-ray?
700 MB
5 - 17 GB
Can be read from + written to.
50 GB
Talk about:
CD-ROM
Data burned on disk surface using lasers making small indentations called pits, disks supplied info e.g. music + software already stored on them, user can read from but not write to, cost determined by what is stored on it.
Talk about:
CD-R
Supplied blank, can record data onto disk once, can be read from many times + used to store data/music/small-scale backup.
Talk about:
CD-RW
Supplied blank, can record + delete data many times, more expensive than CD-R.
Talk about:
Blu-ray disks
Larger storage than DVDs, used for recording high def tv without losing quality, can store digitally encoded video.
Talk about:
Magnetic Tape Streamers
Reads/writes data stored on magnetic tape (DAT), data stored in blocks + gap between each block, slow data transfer because it uses serial access, networks use tape streamer linked to server to make hard disk backups, inexpensive to store large data amounts.
Talk about:
USB flash drives
Pen drives, consists of inbuilt circuit board + USB connector, flash drive active when plugged into USB port, USB connection forms power supply, compact compared to CD, portable, low power, work on principle of plug + play + cost depends on capacity.
Where is the main memory?
What are the 3 types of memory?
Computer Processing Unit (CPU)
ROM, RAM + cache memory.
ROM Memory:
Read/Write?
Volatile/Non-Volatile?
What does it store?
Read from, not written to.
Non-Volatile, permanent.
Booting up program for Windows operating system.
RAM Memory: Read/Write? Volatile/Non-Volatile? What does it store? What depends on the size of RAM? What is held on the hard disk?
Read from or written to. Volatile, lost when switched off. Current programs being used. Speed of processor. All programs + data, those being used and not.
Cache Memory: Where is it located near to? Read/Write? Size + Speed? Purpose?
Close to the processor.
Read from or written to.
Smaller than RAM in capacity, faster access speeds.
Store frequently accessed program instructions.
What is the operating system referred to as?
System Software
What are the main functions of the operating system? (6)
Interface (Communication between user + computer)
Memory Management (Allocates internal memory (RAM) to programs being used, stores + retrieves data on external memory devices)
Resource Management (Controls peripheral devices)
Execution (Boots up computer when turned on)
Error Handling (Deals with errors + response to developer + user)
System Security (Checks + Controls user access to programs)
What are the 4 parts of a GUI?
- Extra features? (4)
Windows, Icons, Menus + Pointers.
Dialogue boxes, toolbars, buttons + tool tips.
Describe:
Windows in a GUI.
Each folder/program/doc open is displayed in separate window.
Can be minimised or maximised.
Maximised window = active window.
Describe:
Icons in a GUI.
Small graphics represent program/file/tool from toolbar.
On desktop as shortcut to folders/programs/docs.
Double-click to open folder/program/doc.
Can be customised + arranged by size/date.
Describe;
Menus in a GUI.
Can be pull down or pop up.
Provides list of options for user to select from.
Can be customised for full menu or short menu.
Describe:
Pointers in a GUI.
Shows position of cursor on screen.
Typical user controls pointer with mouse/tracker pad.
Can move pointer over icon + use mouse buttons to select + open.
What does processing data mean?
Taking raw values + manipulating them to produce information.
What is data?
Raw facts + figures that haven’t been given a meaning.
What is information?
Data which has been given a meaning.
What are forms used for? Paper-based forms? Screen-based forms? What does design quality affect? What does data quality affect?
To collect data. Collect data from people + keyed into computer after. Filled out online or on computer screen. Whether correct data is collected. Information produced.
What should a form include?
Suitable title + instructions which explain purpose, logo, prompt on what data to enter, suitable space for data entry, tick boxes/options buttons to reduce human error.
When designing a form, what should a user ensure?
Divided into sections, suitable font for target audience, font size varies for sections/headings + colour enhances form + layout.
What is OMR?
How does it work?
What are marks converted into?
What is it used for?
Optical Mark Recognition, scans form which have been filled in with marks/ticks.
Uses light to detect position of marks on paper.
Digital data.
National Lottery+ multiple choice tests.
Advantages of OMR? (4)
Fast (many docs can be processed), Accurate (reduce human error), Can be analysed to produce high quality info + staff need minimal training as docs just passed into scanner.
Disadvantages of OMR? (4)
Docs must be in good condition, not creased.
Paper based + specially designed forms expensive.
Not very environmentally friendly (lots of paper)
OMR equipment expensive.
What is OCR?
How does it work?
What is it used for?
Optical Character Recognition.
Transforms paper docs into editable computer docs.
Scanners -> converts doc to text + saved as RTF.
Libraries to digitise + preserve old docs + books.
Royal Mail to sort letters.
Advantages of OCR? (2)
Large quantities of text input quickly, done without retyping.
Disadvantages of OCR? (3)
If dirty/marked, won’t be accurate, expensive, not accurate when scanning forms, small text, shaded photocopies, mathematical formulae + handwritten text.
What are 2 methods of data verification?
Data keyed in twice (entered, compares 2 sets of data, rejected if doesn’t match)
Proofreading
Why is data verification carried out?
To ensure data keyed into computer has been accurately entered.
What is data validation?
What does it ensure?
Checking data to ensure it is acceptable + sensible.
Data is present, correct type, correct range + length.
What are 5 types of data validation?
Presence Check, length check, type check, format check + range check.
What is a presence check?
Data validation, ensures data has been entered into space, common in databases, error message is displayed.
What is a length check?
Data validation, ensures entered data is correct length.
What is a type check?
Data validation, entered data is correct format.
e.g. Numeric, text, date, boolean + currency.
What is a format check?
Data validation, ensures data is correct format. e.g. input mask - AA000
What is a range check?
Data validation, ensures data is within given range.
e.g. 1 - 500
What is a check digit?
How does it work?
Where might they be found?
Digit added to a code to ensure it is valid.
Code is used in calculation + digit is recalculated, if results don’t match error message appears.
ISBN on book or UPC/barcode on products.
What is a UPC?
Universal Product Code, Barcode.
What is data portability?
What determines whether data is portable?
Ability to transfer data from one system/software application to another without having to re-enter it.
Format of data.
What is data compression used for?
Why is it useful?
Reduce the size of a digital file.
Takes less time to download/upload + takes up less storage space.
What software can be used to compress data?
Compressed graphic format? (2)
Compressed music format? (1)
Compressed video format? (1)
WinZip Software
JPEG or GIF
MP3
MPEG
What are 10 common file types?
CSV, RTF, JPEG, MP3, MP4, GIF, TXT, PDF, MIDI, HTML.
What is CSV?
What are the features of CSV?
Comma-separated Variable
Data fields separated by commas, field names entered first, portable files, each record on new line, can be produced by data-logging equipment.
What is RTF?
What are the features of RTF?
Rich Text Format.
OCR scanned docs saved as RTF, portable, can transfer between differing applications e.g. Word to pages.
What is JPEG?
What are the features of JPEG?
Joint Photographic Experts Group.
Common on webpages, compressed, portable.
What is MP3?
What are the features of MP3?
Moving Pictures Experts Group - 3.
Compressed audio, filters out undetectable noise, smaller than CD WAV/AIFF, used by iTunes.
What is MP4?
What are the features of MP4?
Moving Pictures Experts Group - 4.
Compressed video files, high quality.
What is GIF?
What are the features of GIF?
Graphic Interchange Format
Compressed, used on webpages, not great colour
quality.
What is TXT?
What are the features of TXT?
Text/American Standard Code for Information Interchange Text.
Simple, holds letters + numbers but not add info e.g. bold/italic, can be imported from word processor but not always in og format, portable.
What is MIDI?
What are the features of MIDI?
Musical Instrument Digital Interface.
Sound file when dig instruments connected to computer.
What is PDF?
What are the features of PDF?
Portable Document Format.
Portable, smaller than original file, Adobe Reader needed to view/print + mainly read only.
What is HTML?
What are the features of HTML?
HyperText Markup Language.
Used in webpages, browsers programmed to interpret HTML.
What does a network consist of?
A set of computers linked together.
What is a LAN
Example?
Local Area Network, number of computers linked together on a single site, can use copper cabling.
School Network.
What is a WAN?
What do most WANs use?
Example?
Wide Area Network, collection of networks connected using a telecommunications link, using fibre optic cable or satellite.
PSTN.
Internet.
What are the advantages of using a LAN?
Peripherals can be shared, only need 1 copy of software to store on file server + share with computers, users can communicate on network (email/broadcast messages/electronic conferencing), share files/projects + flexible access (log onto any computer to access files).
What is a file server?
What does it do?
Main computer on the network, more powerful, more RAM, more hard disk space.
Manages file + network security + ensures only authorised users can log on.
What does a typical file server hold?
Network operating system software (Windows), application software (Microsoft Office), user files, system software (manages resources + security) + utility software (virus checker).
What does every computer on the network have?
What does it do?
How does it work?
What is a WNIC?
What can be added to computer to enable wireless access to network?
Network Interface Card.
Allows computer to communicate with devices on network.
Network cable inserted into port on NIC connects PC to file server.
Wireless Network Interface Card, means computer can connect to wireless router providing mobile access to network.
USB wireless adapter.
What does a network cable do?
Links computers to network + each other, plugs directly into network card in computer + carries data along cables to + from file server.
What does a switch to?
Connects to group of computers + file server, organises communication between file server + components + can send data to particular computer.
What does a router do?
Shares network connection between devices, enables LAN to connect to internet/WAN + allows 2 networks to communicate, may have integrated security features (firewall), translates info from internet so LAN computers can understand.
What does a wireless router/wireless access point allow?
What does a computer that connects to a wireless router need to contain?
Computer can connect to LAN + enables home users to connect to internet without inconvenience of cables.
Wireless network interface card or be wireless enabled.
What does network software allow?
Computer can communicate with file server and other computers.
What is a communications protocol?
An agreed standard or set of rules for sending or receiving data on a network.
What is the protocol used on the internet called?
What does it ensure?
What does a router connected to 2 networks perform so computers can understand differing protocols?
TCP/IP (Transmission Control Protocol/Internet Protocol)
Makes sure data isn’t lost as it travels from 1 computer to another.
Translation function, allows the computers with differing protocols to communicate.
What must a network be secured from?
Viruses (Trojan horses + worms), unauthorised access (hackers + users), authorised users who may damage important files, unexpected breakdown resulting in lost data + physical damage.
What are 3 measures of basic network security?
Usernames + passwords, levels of access + encryption.
What should a secure password contain?
Combo of letters + numbers, min num characters, regularly changed, confidential, not username, pets name or family name, a word or written down anywhere.
What are levels of access used for?
Limit the things users can do on the network.
In a school network, what can a pupil do?
Access software, use internet, change content + location of user files, change password, use printer + connect + use portable storage devices.
In a school network, what can a teacher do, in addition to what a pupil can do?
Give pupils printer credits, reset pupils passwords, monitor pupil activity + set up shared folders for pupils to use.
In a school network, what can a system manager do, in addition to what a pupil + teacher can do?
Set up new users, remove users, allocate disk storage space to users, copy files between users, allocate network resources (printers) + install software (printers).