P2 T2 L12 - Input and Output Devices

Question 1

What are peripheral devices?

2 points

Answer 1

1. External components that you can touch,

2. used either to get data into or out of the system.

Question 2

What is a device driver?

1 point

Answer 2

1. Software that enables a peripheral to communicate with OS

Question 3

The I/O devices are connected to the computer via ___________.

Answer 3

I/O ports

Question 4

What does a digital camera do?

2 points

Answer 4

1. Records still and moving images in digital form

2. that can be processed further by specialised software.

Question 5

What is a charged couplet device?

2 points

Answer 5

1. A sensor that records the amount of light received

2. and converts it to an equivalent digital value.

Question 6

What is a complementary metal oxide semi-conductor?

3 points

Answer 6

1. A sensor that records the amount of light received
2. and converts it to an equivalent digital value.
3. Alternative technology to charged couplet device

Question 7

What is a pixel?

1 point

Answer 7

1. It is a picture element, an individual dot.

Question 8

What are RGB filters?

1 point

Answer 8

1. Red, green and blue filters that light passes through to create other colours.

Question 9

How does a digital camera work?

5 steps

Answer 9

1. The shutter opens and lets light in through the lens
2. The light is then directed through RGB filters
3. The light then gets focused on the sensor (either a charge-coupled device (CCD) or a complimentary metal oxide semiconductor (CMOS))
4. The sensor breaks the image up into pixels, then records the amount of light received, as a digital value, for each RGB value, for each pixel.
5. Data stored on removable storage device (e.g. SSD)

Question 10

List the suitabilities of a Digital Camera
(4 suitabilities)

NOTE: Suitabilities definition - the quality of being right or appropriate for a particular person, purpose, or situation.

Answer 10

1. Resolution measured in megapixels
2. Low resolution - easy to use, has smaller file size, but pixelated. Suitable for transmission over mobile network.
3. High resolution – accurate reproduction of image, but bigger file sizes. Good for printing and enlarging
4. Raw format (original data collected by sensors) also available in original file

Question 11

What is a barcode reader?

3 points

Answer 11

1. An optical scanner that can read printed barcodes,
2. decode the data contained in the barcode
3. and send the data to a computer.

Question 12

What is UPC? (2 points)

Answer 12

1. UPC – Universal Product Code,

2. the common form of bar code

Question 13

What is POS? (2 points)

Answer 13

1. POS – Point of Sale,
2. the tills in a shop

NOTE: (POS are the tills)

Question 14

Describe the Anatomy of a Barcode

5 things

Answer 14

0 || 12345 || 67890 || 5

1. First digit - number system character (0)
2. Next five digits - manufacturer code (12345)
3. Five digits after that - product code (67890)
4. Last digit - check digit (5)
5. Guard bars ( || ) in between each section - so 3 guard bars in total

Question 15

How does a barcode reader work?

5 steps

Answer 15

1. Scanning head shines LED or laser light onto barcode (Part of POS machine).
2. Light reflects back off barcode into a light-detecting electronic component called a photoelectric cell. White areas of the barcode reflect most light; black areas reflect least.
3. As the scanner moves past the barcode, the cell generates a pattern of on-off pulses that correspond to the black and white stripes.
   (e. g. for the code shown below “black black black white black white black black”, the cell would be “off off off on off on off off.”)
4. An electronic circuit attached to the scanner converts these on-off pulses into binary digits (zeros and ones).
5. The binary digits are sent to a computer attached to the scanner, which detects the code (in the example in point 3 as 11101011).

Question 16

What does RFID stand for? (1 point)

What does it do & what does it use? (1 point)

What is it commonly used for? (1 point)

Answer 16

1. Radio Frequency Identification
2. Using electromagnetic fields to automatically identify and track tags attached to objects.
3. Commonly used in stores to track expensive items and to track cattle.

Question 17

How does RFID work? (6 steps)

Answer 17

1. RFID technology has two components – the reader and the RFID card/tag
2. Reader broadcasts an electromagnetic interrogation pulse (a signal) through antenna
3. Transponder (RFID card/tag) is triggered by the electromagnetic interrogation pulse from the nearby RFID reader device
4. Transponder uses energy to transmit digital data, usually an ID number, back to the reader
5. Reader receives digital data
6. Reader sends digital data to computer system for collecting, logging and processing

====ANOTHER WAY OF EXPLAINING IT====

1. RFID technology has two components – the reader and the RFID card/tag
2. When triggered by an electromagnetic interrogation pulse from a nearby RFID reader device, the tag transmits digital data, usually an ID number, back to the reader.

Question 18

What are the two types of RFID card/tag + explain them? (2 types - 1 point for each)

Answer 18

There are two types of RFID card/tag:

1. Passive tags are powered by energy from the RFID reader’s interrogating radio waves.
2. Active tags are powered by a battery and thus can be read at a greater range from the RFID reader; up to hundreds of meters.

Question 19

Give examples of where RFIDs are used.

6 examples

Answer 19

1. To protect goods in shops from being stolen / high value items like artwork
2. Oyster card in London transport – contactless ticketing
3. Electronic Passports
4. Contactless payment using credit / debit cards
5. Tracking vulnerable patients (e.g., with Alzhemier’s)
6. Tracking and identification of pets and farm animals

Question 20

What is a laser printer? (1 point)

What does the decreasing price of printers and toner cartridges make them? (1 point)

Typical pages per minute? (1 point for typical home printer & 1 point for commercial printer)

Answer 20

1. A device that uses lasers and toner to create mono and colour prints
2. Decreasing cost of printers and toner cartridges makes them a common choice for business and personal use
3. Typical home printer can produce 20 pages per minute.
4. Commercial printers can print 200 pages per minute.

Question 21

How does a laser printer work?

7 steps

Answer 21

1. A rotating drum inside is coated in a chemical that holds negative electric charge.
2. A laser beam is reflected on the drum.
3. Wherever laser beam hits, charge is discharged - creating an image on the drum
4. The drum rotates and attracts powdered toner from its cartridge, to the drum, on the charged sections.
5. The drum rolls the toner onto the paper in the form of the print.
6. The toner is melted onto the paper by heat from a fuser as it passes underneath.
7. The print comes out of the printer.

Question 22

Explain colour printing

4 steps

Answer 22

1. Four different coloured toners are used
2. Toner-to-drum transfer is repeated for each colour
3. Using light on a screen, the three primary colours are used (RGB) to create all possible colours
4. While printing out, four colours are needed – cyan, magenta, yellow and black (key).
   (CMYK)

Question 23

What would you expect of a printer that was to be used to print photographs as well as routine documents? (Give 3 features)

Answer 23

Any 3 of the following:

1. Ability to select different print resolutions / high resolution;
2. Ability to change the thickness of paper used / to accept special photo-paper;
3. Ability to print directly from a memory card or digital camera;
4. Ability to print in colour;
5. Borderless printing;
6. Individual ink cartridges (to reduce wastage);
7. Fast dry inks (to reduce the risk of smudging);
8. Having 6 colour inks for ‘smoother’ tones;
9. Having pigmented inks for better quality;
10. Ability to print on small size of paper (tray)