GCSE Computing: Theory revision questions 1

Question 1

A school has all its computers on a local area network (LAN). What are two benefits of a LAN.

Answer 1

Can share files/can work collaboratively on same files
Can share hardware resources/suitable example (Printer)
Can access their files from any computer or classroom
Can work together from different computers using instant messaging.
Centralised deployment of software to all computers

Question 2

When recording a sound file on a computer, the sound needs to be sampled. What is sampling and how is it used when storing sound?

Answer 2

Sampling is a method of converting an analogue sound signal into a digital file containing binary numbers.

The height and amplitude of a sound wave is measured at regular intervals and converted to binary.

Question 3

What effect does the sampling interval have on the size and quality of the sound file recorded?

Answer 3

If the interval is smaller (if you sample more often) you have more data to store, this results in a larger file. However, as the interval is smaller the sound reproduced is closer to the original audio, resulting in a better quality recording.

Question 4

Why is data stored in computers in a binary format?

Answer 4

Circuit only needs to check for two states to determine if electricity flowing or not flowing, e.g. on or off (1 and 0). This results in more reliable circuits.

Question 5

Why is the ASCII character set not suitable for representing text in all the languages of the world?

Answer 5

ASCII uses 8 bits and so can only represent 255/256 distinct characters. Many more characters are needed for coping with all languages (e.g. Unicode 16bits).

Question 6

What do we mean by the term logic error?

Answer 6

The error does not prevent program running, but does result in the program not producing the expected output.

Question 7

What are two functions of an operating system?

Answer 7

Provides interfaces between user and computer
Determines look and feel of the computer
Provides a platform for software to run on
• e.g. application software such as Microsoft word cannot run without an operating system already installed.
Manages peripherals used by the system
• e.g. Keyboard, Mouse
Manages memory

Question 8

What is open source software?

Answer 8

The source code is distributed with the software
The customer can modify the source code
The customer can redistribute the source code (with the same licence/restrictions)

Question 9

What is meant by a database?

Answer 9

A persistent (stored in secondary storage so that it can be accessed later) and structured/organised store of data, that allows data to be queried/interrogated.

Question 10

Describe two tools in an Integrated Development Environment (IDE) that can help a user when creating a program?

Answer 10

Editor
• Allows Jim to enter the program code
• Colour coding keywords
• Auto-completes code as you type.
Compiler
• Transforms the written source code into machine code.
Debugging tools
• Highlights errors in the code
• Suggests possible solutions.

Question 11

What is meant by a peer-to-peer network?

Answer 11

All computers have equal status, with no central server controlling the network. Data, Files and devices are shared between each other.

Question 12

What is the system cleanup maintenance utility used for?

Answer 12

Searches for and deletes files/programs which are no longer used. For example the software utility could delete temporary files, installation files and registry values which are no longer needed.

Question 13

What is the automatic update system maintenance utility used for?

Answer 13

Checks on the (software manufacturer’s site on the) Internet for newer versions of programs which are installed. If found it download / installs the software.

Question 14

Convert the denary number 55 into an 8 bit binary number

Answer 14

0011 0111

Question 15

Convert the denary number 55 to hexadecimal

Answer 15

37

Question 16

State two tasks which are carried out by the CPU when processing data

Answer 16

Fetches instructions (from memory)
Fetches data (from memory)
Decodes instructions
Executes instructions

Question 17

How do the clock speed and the cache size of a CPU affect its performance?

Answer 17

Clock Speed:
The higher the clock speed the faster the CPU will run, as this represents the number of fetch execute cycles / instructions the CPU can process in a given time.

Cache size
The more cache the CPU has the less time is spent accessing memory, resulting in programs running faster. This is because the cache is faster than memory. The cache is also built into the CPU and contains frequently accessed data.

Question 18

What do the initials DBMS stand for?

Answer 18

Database management system

Question 19

Describe how instructions are stored in binary?

Answer 19

The instruction consists of an operator/op code and an operand. Both the operator and operand are stored as bit patterns. The op code is from a given instruction set and each op code has a unique bit pattern.

Opcodes and Operands (Overview)

An opcode is short for ‘Operation Code’.
An opcode is a single instruction that can be executed by the CPU. In machine language it is a binary or hexadecimal value such as ‘B6’ loaded into the instruction register.

In assembly language mnemonic form an opcode is a command such as MOV or ADD or JMP.
For example
MOV, AL, 34h

The opcode is the MOV instruction. The other parts are called the ‘operands’.

Operands are manipulated by the opcode. In this example, the operands are the register named AL and the value 34 hex.

Question 20

Describe two differences between a high-level code and machine code

Answer 20

In high level code Instructions use words

In machine code instructions are in binary code

High-level code is designed to be read by human programmers

Machine code is to be read/executed by the computer

High level code can be portable/translated for different machines

Machine code is specific to a particular machine