Below Is a Table Comparing Two Types of Microcomputer

Computer System

1. John is an architect. He uses a computer to prepare architectural plans, to communicate with his friends through the telephone lines and to search for information through Internet. He decides to buy a new computer.

Below is a table comparing two types of microcomputer:

Type / Notebook / Desktop
CPU / 200MHz / 300MHz
Main Memory / 64MB / 128MB
Hard Disk / 10GB / 40GB
Monitor / 12" LCD / 17" VGA
Modem / -- / 56 Kbps
Price / $10120 / $7000

(a) After considering his needs, John chooses to buy the Desktop. State TWO ways in which the Desktop can meet the John's needs.

It has a modem for accessing Internet. The Desktop has a larger display area which is better for preparing architectural plans.

(b) Name ONE type of output device that John should add to the Desktop if he wants to produce hardcopy of poster-size architectural drawings.

_Graph Plotter______

__Scanner______

2. Many supermarkets install bar code readers at cashier counters to read the bar code of each item. Besides a reader, a keyboard is also installed as an input device.

(a) Give ONE advantage of not marking prices on individual items.

The prices are stored in the computer and they can be changed easily.

(b) Describe ONE situations when a keyboard, instead of the bar code reader, must be used to enter a bar code number.

If the bar code on a product is damaged, the bar code number can be inputted through the keyboard.

Faster services, higher accuracy.

Computer Network

(Solution is appended at the end of the doc.)

1. Name three common network topologies for LAN and brief describe their connections.

2. What hardware must be used for two computers communicating through a telephone line? Also describe why it must be used.

3. Name three network media and compare their cost and quality for networking.

4. Give one example of a transmission medium that is a direct cable connection and one example of transmission medium that is not a direct cable connection. Also state one advantage and one disadvantage of direct cable connection over others.

5. Give two advantages of network over standalone computer.

6. What is a protocol?

7. What is the function of a router?

8. What is the function of a firewall?

Suggested Solution.

1. Star : each computer is connected to a central computer by a cable.

Bus : All computers are connected to a cable .

Ring : A network cable passes from one computer to another until all computers are interconnected in the form of a ring.

2. A modem. Since telephone line carries analog signal only, digital signal of computer must be converted into analog signal. At the receiving end, the analog signal is reconverted back into digital signal for the computer at the other end to receive.

3. Twisted-pair wire, coaxial cable and optical fibre.

Cost: optical fibre > coaxial cable > Twisted-pair wire

Quality: optical fibre > coaxial cable > Twisted-pair wire

4. Optical fibre is a direct cable connection transmission medium while microwave is not. The transmission speed of direct cable connection is generally higher than a wireless connection. However, cable connection is difficult to setup and not flexible to connect.

5. Sharing resources and communication with others.

6. A set of rules for governing the transmission and receipt of data.

7. A router is used to connection different networks.

8. A firewall is a system or combination of systems that helps to prevent outsiders from obtaining unauthorised access to internal information resources

The Computer System

1. State one advantage and one disadvantage of using floppy disk over a hard disk as a backing store.

2. State one advantage and one disadvantage of using monitor over a printer as an output device.

3. Although magnetic disk is faster than magnetic tape in accessing data, magnetic is still used nowadays for storage. Explain why.

4. Suggest one input device and one output device for a blind computer user and explain why they are suitable.

5. What are the advantages to the performance of a computer if the amount of RAM is increased?

6. In order to construct a school network, both optical fibre and twisted wire are used. Explain what they are different and how they are arranged in a school network.

7. Explain why it is necessary to use modem in computer communications through telephone lines.

8. Give two advantages and two disadvantages of networking.

9. State one advantage and one disadvantage of choosing a custom-made software over a packaged software.

10. List two examples of utility program.

The Computer System – Suggested Solution

1. Advantage: Removable

Disadvantage: Small capacity

2. Advantage: Instant output

Disadvantage: Temporary

3. Magnetic tape is a cheaper medium for backup

4. Input device: Keyboard. Although a blind user cannot see, he can touch.

Output device: Speaker. Although a blind user cannot see, he can hear.

5. Increase the working space for the computer. So more jobs can be done at the same time.

6. Optical fibre transmits optical signal. It is not influenced by electronic noise and it is suitable for long distance communication. Twisted-pair transmits electrical signal. It is easier influenced by electronic noise. It can only be used for short distance communication. In a school network, optical fibre is used for communication between floors while twisted-pair is used for communication in the same floor.

7. Telephone line allows analog signal to go through while computer can only process digital signal. So a modem is necessary to convert between analog signal and digital signal.

8. Advantages: Sharing resources, communication

Disadvantages: Easier for spreading computer virus, risk of hacking.

9. Advantage: Fit your needs.

Disadvantage: Expensive.

10. Disk scanning, disk backup.

Computer Applications – The Computer System ( Quiz)

1. Draw a diagram to show the relationship of the major hardware components. In your diagram, you should indicate the data flow and the control flow.

2. Explain how the following changes can improve the efficiency of a computer.

(a) Increase the RAM size;

(b) Increase the clock rate of CPU;

3. Give one suitable application for each of the following device.

(a) Image scanner;

(b) Bar code scanner;

(d) Optical Mark Reader.

4. Give one advantage and one disadvantage of output data on a printer over a VDU.

5. The access speed of a magnetic tape is significantly lower than that of a magnetic disk. However, it is still widely used in servers. Explain.

6. Give one advantage and one disadvantage of choosing a custom-made software over a packaged software.

7. Browser, Unix, anti-virus program, modem, plotter, computer games, router, editor, word processing program, image scanner.

Classify the above items into (1) Hardware, (2) System software or (3) Application software.

8. Give one difference between CD-ROM and CD-R.

9. EEPROM (Electrically erasable programmable read-only memory) is widely used to replace ROM. Give one advantage and one disadvantage of using EEPROM over ROM to store system program.

10. Touch screen is used in kiosk to replace keyboard. Give one advantage and one disadvantage for such arrangement.

Computer Applications – The Computer System (Quiz) – Marking Reference

Data flow (1)

Control flow(1)

Components (1)

2. (a) Increase the working space for the computer. So more jobs can be done at the same time. (1)

(b) Increase the processing speed of the CPU. (1)

3. (a) Scan photos into the computer. (1)

(b) Scan bar code of product in supermarket. (1)

(d) Multiple-choice worksheet marking. (1)

4. Advantage: Permanent output(1)

Disadvantage: Not instant (1)

5. Magnetic tape is a cheaper medium for backup. (2)

6. Advantage: Fit your needs. (1)

Disadvantage: Expensive. (1)

7. Hardware: Modem, plotter, router, image scanner

System Software: Unix, anti-virus program, editor

Application Software: Browser, computer games, word processing program

8. CD-ROM: Read-only

CD-R: Write once, read many

9. Advantage: The content can be upgraded.

Disadvantage: It may be infected with computer virus.

10. Advantage: Save space

Disadvantage: Not suitable for typing