Hardware

Question 1

Controller or control unit

Answer 1

The controller sends and receives signals from all parts of the computer. It ensures that all processes take place at the right time and in the correct order.

Question 2

ALU

Answer 2

The ALU is the part of the CPU that processes and manipulates data. It performs simple calculations on the data that is temporarily stored in the registers.
The ALU is also able to perform comparisons on data. It is these comparisons that allow programs to make use of choice – e.g. an IF statement in a high-level language.

Question 3

Registers

Answer 3

A register is a storage location found on the CPU where data or control information is temporarily stored. Registers are usually much faster to access than internal memory, since they have to be accessed so often.
An accumulator is a common example of a register. This is the register used by the ALU to store the results of its calculations.

Question 4

Internal memory

Answer 4

Internal memory (sometimes called level 1 cache memory) is fast access temporary storage on the CPU. Data is moved from the registers to the internal memory when it is not being actively used. Data from internal memory can then either be written to RAM or called back into the registers for further processing.

Question 5

Buses

Answer 5

Buses allow data to be transferred to different parts of the computer. There are three main buses used by the CPU.
1. Address bus. When data is saved or loaded from memory, the address at which it is to be stored or loaded from must be sent. The storage address of data always travels along an address bus.
2. Data bus. Data will then need to be moved between several parts of a computer. The path along which data travels is called a data bus.
3. Control bus. The controller uses the control bus to send control signals to different parts of the computer.

Question 6

CPU cache memory

Answer 6

Cache memory is a fast access type of memory; it’s also very expensive. Because of the cost, most computer systems have very little cache memory, e.g. very few kB or MB compared to a Random Access Memory (RAM) where there is likely to be many GB. Cache memory improves the performance of the CPU as it is able to provide instructions and data to the CPU at a much faster rate than another system memory such as RAM. The more cache memory your system has, the better its performance is likely to be.

Question 7

RAM

Answer 7

RAM is used for the temporary storage of currently running programs and data, e.g. the operating system, a text editor program. It consists of a large number
of store locations, each of which is identified by a unique address. The
data in each store location can be changed. RAM is volatile – data is
lost when the power is switched off.

Question 8

ROM

Answer 8

ROM is used for the permanent storage of data. The data in each store location cannot be changed. ROM is permanent – data is not lost when the power is switched off.

Question 9

Flash memory

Answer 9

Flash memory is used for the permanent storage of data. However, the data stored in flash memory can be changed. Flash memory is permanent – data is not lost when the power is switched off.
Example: Flash memory can be used for storing the programs such as the BIOS, which is advantageous as the BIOS can then be upgraded.

Question 10

RAM cache memory

Answer 10

RAM Cache memory is used for the temporary storage of frequently accessed data and instructions. It consists of a small number of store locations that can be accessed very quickly by the CPU; it is quicker than RAM. Cache memory is volatile – this means that data is lost when the power is switched off.

Question 11

Optical storage

Answer 11

Optical storage media uses technology such as lasers. Laser beams are projected onto a CD/DVD or Blu-ray disc and if light is reflected back, then data is read as a 1. If light is not reflected back, data is read as a 0. Lasers are used to read and write information on a disk.

Question 12

Magnetic storage

Answer 12

This technology is used in hard disks and tapes. Data is stored on a magnetic medium, which can be a disc or a tape, by writing data using a write-head. Data can then be read by the read-head.

Question 13

Solid state technology

Answer 13

Solid state technology is used in storage media such as flash memory sticks. The technology is called solid state as it doesn’t have any moving parts, such as a read-head in magnetic storage. Solid state storage technology is increasingly used to replace both magnetic and optical storage, especially in mobile devices, where its low power consumption and high speed access is advantageous.

Question 14

Motherboard

Answer 14

The motherboard is the main circuit board of a computer. The CPU and ROM will be mounted on the motherboard, which also provides RAM expansion slots, USB ports,
PCI slots for expansion cards and controllers for devices such as the hard drive, DVD drive, keyboard and mouse.

Question 15

GPU

Answer 15

A GPU is a microprocessor that performs the calculations needed to produce graphic images on screen. The CPU performed these calculations initially, but as more complex applications were developed, such as 3D graphics and video quality animations, the GPU was introduced to offload those tasks from the CPU.

Question 16

Integrated GPU

Answer 16

An integrated GPU uses the computer’s RAM. An integrated unit is cheaper than installing a dedicated GPU. It generates less heat and uses less power. They are perfect for general graphics processing such as watching or editing videos and word processing.

Question 17

Dedicated GPU

Answer 17

A dedicated GPU has its own video memory. Dedicated cards provide the best visual experience. They are used by people such as graphic designers and people who play a lot of games, but they use more power and need a good cooling system. GPUs are also used to mine digital currency due to their processing ability.

Question 18

Sound cards

Answer 18

Sound cards may be on the motherboard or designed to fit a PCI slot. They enable the computer to output sound through speakers, record sound from a microphone and manipulate sound stored on a disk. Sound cards convert analogue input signals into digital data and reverse this process for audio output.

Question 19

Embedded systems

Answer 19

An embedded system is a combination of software and hardware that performs a specific task rather than a general-purpose computer that is designed to carry out multiple tasks.
Embedded systems are included as a part of a complete device often with hardware and mechanical parts. As the systems carry out specific tasks they can be designed to be small and have a low cost. Mass-production of embedded systems can save large amounts of money.

Question 20

Networks

Answer 20

A network consists of a number of computer systems connected together. There are many advantages and disadvantages of using a computer network over a stand-alone computer.

Question 21

Advantages of networks

Answer 21

 Share hardware
 Share software
 Share data/files
 Easier for internal communication/can
send email
 Central backup
 Easier to monitor network activity
 Centrally controlled security
 Can access data from any computer

Question 22

Disadvantages of networks

Answer 22

 A network manager may need to be employed – expensive
 Security problems – files sent between computers could spread a virus
 Hackers can gain access to data more easily
 If the server is down, all workstations on the network are affected
 Initial cost of servers, communication devices etc. can be expensive

Question 23

Bus network

Answer 23

The computer systems, also called the nodes of the network, are all connected to a single cable on which data can be sent, called the bus. A bus network has terminators on each end,
which are needed to ensure the network functions correctly.
The bus carries data packets along the cable. As the packets arrive at each computer system, it authenticates the destination address contained in the packet to see if it matches its own address. If the address doesn’t match, the computer system ignores the packet. If the address of the computer system matches the address contained in the packet, it processes the data.

Question 24

Advantages of bus networks

Answer 24

 Easy to implement and add more computer systems to the network
 Quick to set up – well suited for temporary networks
 Cost-effective – less cabling

Question 25

Disadvantages of bus networks

Answer 25

 It is difficult to troubleshoot the bus
 Limited cable length and limited number of
stations – performance degrades as
additional computers are added
 If there is a problem with the main cable or
connection, the entire network goes down
 Low security – all computers on the bus
can see all data transmissions
 Proper termination is required
 Data collisions are more likely, which
causes the network to slow down. A collision is when two computers try to send a data packet at the same time

Question 26

Ring network

Answer 26

In a ring network, computer systems are connected in a ring or a loop. Data packets are sent around the ring, being passed from one computer system to the next until they arrive at their destination.

Question 27

Advantages if ring network

Answer 27

 Data is quickly transferred without a bottleneck – consistent data transfer speeds
 The transmission of data is relatively simple as data packets travel in one direction only
 Adding additional nodes has very little impact on bandwidth
 It prevents network collisions

Question 28

Disadvantages of ring networks

Answer 28

 If any of the computer systems fail, the ring is broken and data cannot be transmitted efficiently
 If there is a problem with the main cable or connection, the entire network goes down
 It is difficult to troubleshoot the ring
 Because all nodes are wired together, to
add a another you must temporarily shut down the network

Question 29

Star network

Answer 29

In a star network, each computer system is connected to a central node, also known as a hub.

Question 30

Advantages of a star network

Answer 30

 Good performance/fast network speed
 Easy to set up
 Possible to add more computer systems
without taking the network down
 Any non-centralised failure will have very
little effect on the network
 Minimal network collisions
 Better security

Question 31

Disadvantages of a star network

Answer 31

 Expensive to install – more cabling required
 Extra hardware required, such as a hub

Question 32

Mesh networks

Answer 32

In a mesh network, each computer system is directly connected to as many other computer systems as possible. The image above shows a full mesh network, where all computer systems are connected to each other. It is also possible to have a partial mesh network, where only some of the computer systems are connected in similar fashion to a mesh topology, while the rest are only connected to one or two devices. This is called a partial mesh network. The mesh topology is the most common network topology used on wireless networks.

Question 33

Advantages of a mesh network

Answer 33

 Data can be transmitted from different nodes simultaneously
 Mesh topologies can withstand high traffic
 Each connection can carry its own data load
 If one node fails, there is always an alternative present, so data transfer isn’t affected
 A fault can be diagnosed easily
 Expansion and modification in topology
can be done without disrupting other
nodes
 Provides high levels of security and
privacy

Question 34

Disadvantages of a mesh network

Answer 34

 Installation and configuration can be difficult as the network grows
 Cabling costs are high
 There is a high chance that many of the
network connections will be redundant
 Set-up and maintenance of mesh
topologies is very difficult
 Administration of the network is difficult