Unit 3 Chap 9 & 10 (1-18) Flashcards
What is a computer?
Electronic machine that stores, receives and processes data very quickly using a stored program.
What is hardware?
Physical parts of the computer you can see & touch.
e.g. Screen, printer, keyboard
What is a program/software?
Set of instructions to instruct computer to carry out a task
What is a peripheral device?
Any piece of hardware which is external to the processor.
What are input devices?
Devices used to get data into the computer
What is the CPU?
Central Processing Unit.
Brain of computer which carries out all processes.
e.g calculations
What is the motherboard?
Main printed circuit board. Contains COU, memory boards & other circuit boards required by computer system.
What is a video card?
Printed circuit board which generates images for computer’s VDU. Can determine resolution & colours used on screen.
What are output devices?
Devices which provide information output in a format humans can understand.
e.g. screen display & printouts
What are backing stores?
Devices used to permanently store data when computer is switched off
e.g. hard disk, CD
What is ASCII
American Standard Code for Information Interchange
Diagram of the structure of a computer system?
Input —> CPU —-> Output
|
|
Storage
Give 5 input devices
Keyboard
Mouse
Tracker Pad
Joystick
Touch Screen
Scanner
Digital Camera
Graphics Digitiser
Microphone
Musical Instrument Digital Interface (MIDI)
What is a keyboard made up of?
What are most keyboards called?
What sections is the keyboard arranged into?
Keys
QWERTY
Alphabet keys, Function, (F) keys, Numeric keys (2 sets),
Arrow keys command keys (Insert, delete)
Advantages of keyboards? (4)
Most computers come with a keyboard supplied
People are used to using them to enter data, no training
A skilled typist can enter data very quickly
Specialist keyboards are available (Ergonomic, gaming)
Disadvantages of keyboards? (5)
Easy to make mistakes when typing data
If you can’t touch type, it can be take ages to enter data
Not suitable for creating diagrams
Disabled people find them difficult to use
Excessive use can lead to R.S.I.
What is a concept keyboard?
Can use a variety of programmed overlays.
Overlays allow keys to be defined as words or pictures.
Teachers can use them when kids are too young to understand a keyboard.
Use in fast food restaurants or vending machines.
What are function keys?
Used for special pre-programmed functions within an application.
e.g. F4 in Excel sets an absolute cell address
What does the control key do?
Holding it down & pressing other key combinations initiates different actions.
e.g. Ctrl + C = copy
Ctrl + V = paste
What does the shift key do?
Holding it with another key gives the 2nd character on key or capital letter for an alphabetic character.
What are the cursor keys used for?
Move cursor around a document
e.g. in Excel, move between cells
What is a hot key?
Any shortcut key or combination of keys.
When pressed, a task is carried out.
What is a mouse also called?
What does it do?
What does it have?
What does left/right clicking do?
Pointing device
Enables you to control what happens on screen
Left & right button & central scrolling wheel
left = choose
right = menu
Where do you get tracker pads?
Laptops
Advantages of tracker pads (3)
Useful for laptops when mice aren’t practical
Pad’s position is fixed, unlike a traditional mouse
Short finger movements required to move the cursor
Disadvantages of tracker pads (3)
Takes practice & skill to control position
Gloves can’t be worn
Moist, sweaty or calloused fingers can disrupt signals
What does a joystick do?
What machines do they control?
Moves in many directions. Have buttons too.
Cranes, trucks, powered wheelchairs
Advantage of joysticks (1)
Better gaming experience for racing or flying computer games
Disadvantages of joysticks (2)
More difficult to control than a traditional mouse
Not very robust & break easily
Advantages of touch screens (2)
Easy to use - no training
No extra peripherals e.g. mouse
Disadvantages of touch screens (4)
Not suitable for inputting large amounts of data
Not very accurate - difficult with fingers
Tiring to use for long periods
More expensives than alternatives e.g. mouse
What are scanners used for?
How do they work?
What is the most popular type?
Convert images/text into a digital format.
Shines a beam of light onto the surface of an object, light reflects onto a sensor which detects colour. This then builds up the digital image.
Flatbed scanner
Advantages of scanners (3)
Very accurate & produce high quality images
Any image can be included in electronic documents
Can be enhanced with a graphics application
Disadvantages of scanners (3)
Can take up lots of memory space
Lose some quality in scanning & digitising process
Quality of final image depends on original image
What does a digital camera do?
Records images electronically on a memory card.
They can be downloaded onto a computer & printed, stored or maniptulated with editing software.
Can be deleted
Quality depends on res/num of pixels.
Advantages of digital cameras (5)
No film needed, no developing costs to see picture
Can be viewed immediately & deleted
Can be edited, enlarged or enhanced
Can be incorporated into documents/websites
Extra memory sticks can be purchased for storage
Disadvantages of digital cameras (3)
More expensive than cameras with film
Images often have to be compressed
When memory is full, images must be downloaded or deleted before taking more pictures.
What are graphics digitisers for?
What do they consist of?
Designers can create accurate drawings
Flat pad (tablet) & stylus
Advantages of a graphics digitiser (2)
More natural to draw with a pencil style implement rather than a mouse
Very accurate
Disadvantages of a graphics digitiser (2)
Not suitable for general selection work.
More expensive than a mouse
How do microphones work?
Sound detected by microphone & electrical signal transmitted to computer
Special hardware converts it into digital data.
What are MIDIs?
How do they work?
Keyboards which are connected to a computer so when a person plays the keyboard, the frequency, pitch & other info is converted to digital info.
Can be stored on computer & mixed.
Advantages of MIDI (3)
Music can be produced be people who aren’t experts
Can be easily edited without having to re-record the whole piece.
Voice tracks can be integrated with the music
ipad eg. garageband
What is a VDU?
What is the average size?
What is the picture made up of?
What is an SVGA monitor?
What are multimedia VDUs?
What is multimedia?
Visual Display Unit
17 inches diagonally
Pixels (resolution)
Good quality, high resolution
Monitors with built-in speakers & microphones
Combination of text, graphics, voice, video & sound to produce a presentation/website
Give 3 types of output device
VDUs
Speakers
Printers
What are 4 types of printer?
Impact/dot matrix printer
Ink Jet Printer
Laser Printer
Plotter
How do impact printers work?
What do they create?
Strike tiny pins against a carbon ribbon. Very noisy.
Carbon Copies
Advantages of impact printers (2)
Low operating costs (£50+)
Carbon copies can be created by using carbonated paper
Disadvantages of impact printers (4)
Poor quality of print
Very slow (200 CPS/Characters per second)
Very noisy
Can’t produce colour copies.
How do inkjet printers work?
Fire a droplet of ink at page by boiling in microscopic tube & letting steam eject droplet
Advantages of inkjet printers (6)
Good resolution (300-600 dpi/dots per inch) 3ppm
Cheap £50+
Small - ideal for home/office
Light
Very quiet
Can print black & white or colour on same page
Disadvantages of inkjet printers (6)
Slow compare to laser printers
Colour printing is slow
Expensive consumables
Cartridges replaced more frequently than laser
Ink smudges in printout gets wet
If left unused for long periods of time, cartridges dry out
What is used instead of ink in a laser printer?
How is it fused onto the paper?
Powdered ink (toner)
By heat & pressure
Advantages of laser printers (5)
Very high resolution (600-1200 dpi)
High quality printouts
Very fast (10-20ppm/pages per minute) Almost silent
Running costs low (toner expensive but last long)
Disadvantages of laser printers (5)
Very expensive (£300+)
Expensive to repair
Can’t use continuous/multi-part stationary for carbon copies
Only A4 or A5 paper can be used
Large & heavy
What are plotters for?
When are penless plotters used?
What are they used to create?
Accurate, high-quality diagrams
High density drawings e.g. maps/circuit diagrams
Architects plans, maps, advertising posters
Advantages of plotters (2)
Quality is as if an expert drew them
Larger paper sizes can be used
Disadvantages of plotters (3)
Slow because each line is drawn separately
More expensive
Low quality text printouts
What do magnetic hard disks consist of?
Where is data stored?
What is their capacity?
What is their access speed?
Metal disks mounted on a spindle. Read/write heaad on each surface. Both sides.
60 Gb
Very fast
Give 3 optical disks
CD-ROMs
Writeable CDs
DVDs
How much storage in a CD?
What is the access speed in a CD?
650Mb
Fast
What is a WORM?
What is a CD-ROM?
What is a CD-R?
What is a CD-RW?
What is a DVD?
What is a DAT?
Write Once Read Many times
Compact Disk Read Only Memory
Compact Disk Recordable
Compact Disk ReWriteable
Digital Audio Tape (Magnetic Tape Streamer)
What is the storage in a DVD?
What is the access speed of a DVD?
17 Gb
Fast
What is the storage in a USB Flash/pen drive?
What sort of memory is it?
What is the access speed?
128Mb - 2Gb
Flash
Fast
What is the storage in a Tape Streamer?
What is the access speed?
60Gb
Slow
What is the storage in a Blu Ray?
What is the access speed?
50 Gb
Very fast
What is ROM?
What does it store?
What sort of memory is it?
Read Only Memory
Booting Part of Operating System Program
Non volatile
What is RAM?
What sort of memory is it?
What is IAS?
What is the size?
Random Access Memory
Volatile
Immediate Access Store
512 Mb
What is cache memory?
What does it store?
What sort of memory is it?
Price?
Fast access RAM memory
Recently & frequently accessed files (webpages)
Volatile
Expensive
What does the operating system do?
Examples? (2)
Where is it stored?
Enables hard & software to work together.
Windows Vista & Xp
Hard disk
What happens when you switch on a computer?
Power sent through circuits & CPU loads the boot program form the ROM chip.
Tells CPU hardware & software in system.
Checks everything is functioning properly & loads default operating system from hard disk.
4 tasks of the operating system
Share processor time between applications running
Share RAM memory between applications running
Manage devices connected to computer
Provide a user interface
What is a GUI?
What is also described as?
Graphical User Interface
WIMP Application
What is WIMPs
Windows
Icons
Menus
Pointers
What are windows?
Shows current tasks being performed.
Each window has a title bar.
Many windows can be open.
What are icons?
A picture that represents a file or command
What are menus?
List of options on a drop down menu in a window
What are pointers?
A cursor/arrow that can be moved about a window to make selections from menus.
What is resolution?
A measure of the quality of an image
What is a check digit?
A digit added to the beginning or end of a number to verify the number entered is an authentic code.
What is a blind carbon copy?
Sending an e-mail to recipients where they can can only see their own details and not those of other recipients.
What is a Bitmap
An image not optimised for use on the Internet
What is Digital?
A name used to describe data held in 1s and 0s
