1 Explain, using examples if appropriate, the meaning of the following computer terms.

Icon – graphical symbols offering choices.

read only memory (ROM) – It is a non-volatile memory that cannot be written to.

buffer- temporary store that holds data being transferred between devices, often to compensate for different speed.

Verification- Checking input for errors usually by double entry or on screen checking.

operating system –is a set of software routines that communicate between application programs and the hardware. It does jobs like file management, memory management or peripheral control. Example is DOS.

hacking – is the unauthorized use of a computer.

2 State three benefits of using modules to write a program

1. It enables the program to be developed by a team

2. It is easy to debug

3. modules may be prewritten

3 (a) State the two advantages of using robots in a car factory.

1. Robots reduce labour costs

(b) Describe one task in the process of making the cars that can only be done by

humans.

Humans checking paint work, look for imperfections, program the robots

4 (a) Describe one use of a multimedia system in a school.

(b) Give one reason why it is used.

Multimedia systems use video, animation or sound.

5 A college has linked its stand-alone computers together to form a local area network

(LAN).

State three advantages for doing this

1. users can access the same files

2. users can share hardware

3. messages can be sent between terminals

State three disadvantages of networking computers

4. a network is prone to hackers

5. a virus can spread to all of the terminals

6. all the computers go down if the file server goes down.

6 A shop owner uses a manual stock control system. Give four reasons why the owner

would want to change to a computer system which uses point-of-sale (POS)

terminals.

automatic stock control

recoding transavction

itemized recripts

less errors

7. The following method is an example of encryption used by computers. Columns always contain four Characters. Rows can contain as many characters as are needed.

T G I H I

O H S E G

N T * * H

I * T N T

Reading down, the column message can be translated as:

TONIGHT*IS*THE*NIGHT

Reading across, the massage would be sent as :

T G I H I O H S E G N T * * H I * T N T

a) The following data have been received:

I L E E A * L * R T W * T E * I B H * 2

What is this message?

I L E E A

* L * R T

W * T E *

I B H * 2

I*WILL*BE*THERE*AT*2

b) State one reason why data are encrypted.

Encrypting data for security

Encrypting data is harder or impossible to understand or alter.

8 A desktop publishing (DTP) package is to be used to improve the appearance of the following invitation.

Give two ways of obtaining a picture to improve the party invitation

1. a scanned picture

2. importing a picture file from the internet or clipart library.

Give four other features of the DTP package that could be used.

3. Different font

4. frames

5. colour

6. cropping or columns or text wrap

9 The spreadsheet shows details of drinks sold during one week.

The amount of TEA sold should have been entered as 20. Describe how the user of the spreadsheet would make this change.

Click on cell C6 and type 20

The PROFIT $ on each item sold is the

(SELL PRICE$- COST PRICE$) X SOLD

Write a formula that has been inserted into cell F2 to do this.

(E2-D2) * C2

The row for the ORANGE juice was inserted after the rest of the spreadsheet had been created. Describe how this insertion should have been done.

Click on a cell on row 4, select ‘insert row’ from the menu and then enter

the data.

Explain how the user could sort the data into alphabetical order of DRINK.

Highlight cells A2-F7, select sort ascending or select from toolbar.

10 A hardware supplier keeps a file of people who have problems with their purchases and have telephoned for advice. Several records are shown in the diagram.

11 Read the algorithm

set total to zero

set counter to zero

input first rainfall

repeat

add rainfall to total

add one to counter

input next rainfall

until rainfall is less than zero

divide total by counter

Output result

Determine the result when the following data are input.

22

12 A microprocessor controls the temperature and lighting in a room Control bits are sent to turn parts of the system on or off, i.e. 1 is on and 0 is off.

..not in use..

cooler light

blower dehumidifier

Describe what should happen when the above bit pattern is sent.

The blower and cooler were on and the dehumidifier and light were off.

If the room temperature is above 22^o C, then cool air is sent around the room using the blower and the cooler. If the humidity is greater than 75, then the de-humidifier is on. If the light-level is below 18, then the lights com on. Write down the bit pattern that would be set when the room temperature is 22^o C, the humidity is 77 and the light-level is 17.

13 People are concerned about the increasing noise level of the traffic on the road where they live. Data logging is to be used.

state two items of hardware that data-logging system should use.

1. noise-level sensor

2. data logger, microphone or Analogue to digital convertor (ADC)

Evidence is needed to support a claim that the noise level has become unacceptable.

ii) circle a suitable time interval for collecting the data

iii) circle a suitable period of time for the whole monitoring process to take place.

The data from the data logger are stored in the computer system ready for processing. Describe how a report can be produced using various software packages.

14 A family uses their computer for home shopping, electronic banking and sending e-mail messages to their friends around the world

Describe one advantage and one disadvantage of using this method for shopping

Advantage: shoppers do not have to leave home

They have a wider variety goods from which to choose.

Disadvantage : Credit card payment method might not be secure

People would not be able to touch the merchandise

There is a time delay between purchasing and receiving the

goods.

Describe two bank services which would not be available.

1. depositing and drawing out cash

2. changing currency

Give two benefits of sending messages using email rather than by the ordinary letter post.

3. It is faster to send email as the receiver received it almost immediately

4. It is cheaper to send email as no stamp is needed.

15 A database is used to stored details of staff. The format of the first four fields is as follows:

STNAME Text Staff Name 50 characters

STADDRESS Text Staff Address 80 characters

TELNO Text Telephone Number 20 characters

DOB Date Date of Birth 6 characters

Complete the boxes below for the next numeric field which could be in the staff record.

These data need to be protected from possible misuse. State two precautions which may be taken to do this.

1. Password may be issued for authorized person only

2. Data locks, encryptions or a firewall

Give one situation, in each case, when the data would be amended, inserted and deleted.

Amended : when there is a change in the staff address

Inserted : when new staff has joined the company.

Deleted : when existing staff leave the company.

Describe two precautions that should be taken to enable data to be recovered after a system failure.

3. Backups

4. file generations

5. parallel systems

16 A microprocessor controls an oven used to bake bread.

Describe the input data needed by the microprocessor.

Temperature, time, program number, weight of the dough.

Write an algorithm that uses the input data to control the process of baking the bread.

1. Select program

2. calculate time against weight

3. input required time

4. input required temperature

5. repeat

6. read temperature

7. read time

8. if temperature is below the required temperature then

9. turn the heater on

10. else

11. turn the heater off

12. end if

13. until time is equal to required time

14. sound buzzer

17 An expert system is being used in the search for minerals. Describe the inputs, processing and outputs of this system

inputs: depth, the quantity of the mineral that already exists in the vicinity, the type of mineral being searched for, the location and the foil or rock formations in the area.

Processing: inference engine searching the knowledge base using the rules and making comparisons

Output: type of mineral to be found, the depth and predictions.