Targeted Practice

Question 1

L1
1) What is a computer?
2) How can computer systems be categorised?
3) What do these systems mean?

Answer 1

1) A computer is a programmable device that takes in data, processes it into useful information, and then outputs the information so it can be used.
2) Computer systems can be categorized as either:
- General purpose
- Embedded systems
3) General purpose computers are devices that have a variety of uses, the user chooses the task for the computer to complete.
An embedded system is a computer system with a specific purpose or function, which is built into a physical device or machine.

Question 2

L2
What are the functions of these CPU components?
1) Buses
2) Registers
3) Clock

Answer 2

1) Buses: many parallel wires connecting components, which transfer data or instructions between different CPU components.
2) Registers: holds data used when executing an instruction, and holds the result of executing an instruction.
3) Clock: it controls the number of instructions carried out each second and manages cycles per second.

Question 3

L5
1) What are the characteristics of solid-state storage?
2) What are the advantages of solid-state storage?
3) What are the disadvantages of solid-state storage?

Answer 3

1) Solid-state consists of:
- No moving parts to read or write data
- A collection of circuits wired together to store binary data
- The collection of circuits are wired to form a grid
2) Advantages of solid-state storage:
- Fast
- Lightweight
- Durable: they last a long time as they have no moving parts
3) Disadvantages of solid-storage:
- Expensive cost per MB
- Typically a lower capacity than hard drives
- They have limited read/writes

Question 4

L6
1) What are the advantages of magnetic storage (state 4)?
2) What are the disadvantages of magnetic storage (state 3)?

Answer 4

1) Advantages of magnetic storage:
- Cheap for large capacities
- Infinitely rewritable
- Reliable for long periods of time
- Faster read speeds than optical
2) Disadvantages of magnetic storage:
- Damaged if dropped or exposed to a magnetic field
- Slower read speeds than solid state
- Require a lot of power to run

Question 5

L3
Explain the fetch-decode-excecute cycle in detail

Answer 5

Instructions are loaded into RAM from secondary memory.
The instructions are stored in RAM in numbered memory locations.
Fetch:
The CPU sends a signal along the address bus requesting an instruction from a specific numbered location in RAM.
The instruction is transferred via the data bus to the CPU.
Decode:
The CPU decodes the instruction.
The CPU may fetch data held in memory if referenced in the instruction.
Execute:
The CPU executes the instruction.
The result may be stored back into RAM.

The cycle repeats.

Question 6

L10
1) State the different types of programming languages
2) Explain the main differences between the two

Answer 6

1) There are different levels of programming language:
- low-level language
- high-level language
2) High-level languages require the use of a compiler or an interpreter for their translation into the machine code. Low-level language requires an assembler for directly translating the instructions of the machine language.

Question 7

L11
1) What are the two types of low level languages?
2) What are the differences between the two types of low level languages?
3) Describe what assembly language is used for
4) What kind of code is executed by the processor?

Answer 7

1) Machine code and assembly language are low-level languages.
2) Machine code is a low level language that is directly understood by the CPU, and is written in binary. It is specific to a processor or family of processors.
3) Assembly language is often used to develop software for embedded systems and for controlling specific hardware components. Assembly language has a 1:1 correspondence with machine code.
4) Processors execute machine code. Each type of processor has its own specific machine code instruction set.
All programming code written in high-level or assembly languages must be translated.

Question 8

L11
1) State the different types of programming languages
2) State the three common types of program translator
3) Explain the main differences between these three types of translator

Answer 8

1) There are different levels of
programming language:
- low-level language
- high-level language
2) There are three common types of program translator:
- Interpreter
- Compiler
- Assembler
3) A compiler translates high level programming languages into machine code. It translates all the code in one go.
An assembler translates assembly languages into machine code, and each line of assembly language is assembled into a single machine code instruction.
An interpreter translates high level programming languages into machine code. An interpreter translates source code into machine code one instruction at a time. The resulting machine code is then executed immediately. Interpreters do not produce any machine code so the program needs to be translated each time it is executed. They call machine code subroutines within their own code to carry out commands and directly execute the instruction. If a runtime error is found the interpreter stops.

Question 9

What is the function of the following registers:
1) Current instruction register (CIR)
2) Memory address register (MAR)
3) Memory data register (MDR)

Answer 9

1) Current instruction register (CIR): Holds the current instruction that the processor is executing
2) Memory address register (MAR): Temporarily stores the memory addresses used when searching for data in RAM
3) Memory data register (MDR): Temporarily holds the data (data values or instructions) that are read from or written to the main memory

Question 10

What is the function of the following registers:
1) Program counter (PC)
2) accumulator (ACC)

Answer 10

1) Program counter (PC): Holds the address of the next instruction to be executed by the processor
2) Accumulator (AC): Stores the result of any calculation

Question 11

Describe the functions performed by the operating system (state 5)

Answer 11

• Memory management: it manages the computer’s memory, and can control which parts of memory are being used by which process.
• Input/ output management: it manages input/ output devices, controls network communication and allows devices to send and receive data.
• Managing storage: it manages secondary storage devices, manages loading data and programs into the computer’s memory and manages storage space.
• Managing security: it manages user authentication, protects against malware, and blocks access to specific vulnerable operations or system areas (such as installing software).
• Managing applications: it controls access to applications and prevents users or processes from using unauthorised programs.

Question 12

L8
1) What is main memory?
2) Explain how main memory is used?

Answer 12

1) Main memory is any form of memory that is directly accessible by the CPU, except for cache and registers.
2) It stores instructions whilst a program is being executed. The CPU fetches instructions from main memory to decode, and stores the results of the execution of the instructions in the main memory.

Question 13

L10
1) Explain why most programs are written using high level languages (state 9)
2) State the advantages of low-level language programming compared with high-level language programming (state 3)

Answer 13

1) - High-level languages have built-in functions
- High-level languages have built-in libraries
- High-level languages have more support
- High-level languages can be less machine dependent/more portable
- High-level lanugages usually requires fewer lines of code to be written
- Usually quicker to develop code in high-level languages
- It is easier to find mistakes in code
- The code is easier to understand and maintain
- It is easier to structure code in high-level languages
2) Programs written in assembly or machine code run faster, programs require less memory when executing and programs written in assembly language have no extra code added by the computer.

Question 14

1) What is hardware?
2) What is software?

Answer 14

1) Hardware is the physical components of a computer system.
2) Software is the programs, code or instructions that are executed by the hardware.

Question 15

1) Explain why secondary storage is required in a computer system
2) State 3 examples of volatile memory in a computer system

Answer 15

1) Secondary storage stores all the user’s files, applications and operating systems. Secondary storage is needed to store data or files when the computer is switched off on a long term basis.
2) RAM, cache and registers

Question 16

L1
1) What are the advantages of the peer-to-peer model?
2) What are the disadvantages of the peer-to-peer model?

Answer 16

1) Advantages of the peer-to-peer model:
- Clients are not dependent on one single server
- Resources can be shared between computers (e.g. printers)
- It doesn’t require expensive equipment to set up
- If more than one computer in the network hosts a file, then the client can request it from the device that is closest
2) Disadvantages of the peer-to-peer model:
- Using a shared peripheral, like a printer, can lead to a computer slowing down whilst processing many requests
- If a host computer breaks down, this can cause files or peripherals that are hosted by it to be unavailable
- There is no central backup system
- There is no central way to provide security for the network

Question 17

L1
1) What is a computer network?
2) What are the advantages of a computer network?
3) What are the disadvantages of a computer network?

Answer 17

1) A computer network is more than one computer connected together and able to share resources.
2) Advantages of a computer network:
- You can share documents easily
- Share devices, like printers
- Users can connect with people in other countries
- Software and storage can be shared across the network
- It can be more reliable
- Backups can be centralised
3) Disadvantages of a computer network:
- Networks are expensive to set up
- Hackers could gain access to an entire network if it isn’t protected
- Viruses can be spread through connections
- Managing security over an entire network requires specialist skills
- Managing a network requires specialist skills

Question 18

L7
1) Define IP address
2) Explain the WWW
3) What is the DNS and why is it used?

Answer 18

1) A term used to describe the numeric pattern assigned to each device on a network. Used to locate devices. Every device on the internet has its own, unique IP address.
2) WWW stands for the World Wide Web. It is a collection of web pages that can be browsed using a web browser.
The internet can be used to access the WWW. The internet and the WWW are not the same thing.
3) The DNS is a collection of servers that lists commonly used website addresses and their IP addresses. There are thousands around the world.
It is used because it would be very hard to remember the IP address of every website that you want to use, so a naming system (DNS) is used instead.

Question 19

L7
Explain how a computer finds the IP address for a website

Answer 19

1. First it checks with your ISP’s (Internet Service Provider) DNS server. This contains the most commonly visited website IP addresses that their customers view.
2. If the website’s IP address can not be found here then it checks the fastest available root DNS server. The root DNS server is at the very top of the DNS server hierarchy.
   It knows the location of all of the DNS servers on the top level domain (TLD).
3. If the computer is trying to access the IP address for a .com URL then it will go to the .com TLD server.
4. The .com TLD server will then have a list of all of the authoritative name servers (ANS). These are the web servers that use a .com extension.
5. The authoritative name servers (ANS) for Google will be able to tell your computer the IP address for google.com.

Question 20

L8
1) Define web server
2) Define the cloud/ cloud computing

Answer 20

1) A web server is a server dedicated to providing services for the world wide web.
2) The cloud is a term used to describe software and storage that are used through the internet.

Question 21

L9
1) Explain FTP
2) Explain UDP
3) State what POP, IMAP, and SMTP protocols are used for?

Answer 21

1) FTP (file transfer protocol): deals with uploading and downloading files from a server.
2) UDP stands for User Datagram Protocol.
Messages are sent instead of packets - chunks - it is often faster. It allows for gaming or video calls over the internet.
3) POP, IMAP, and SMTP protocols all deal with email communications.

Question 22

L9
1) Define POP
2) Define IMAP
3) Define SMTP

Answer 22

1) POP stands for post office protocol. This type of email protocol is less common nowadays. The POP protocol retrieves the email from the email server, delivers it to your computer or device, and then deletes it from the email server.
2) IMAP stands for internet message access protocol. IMAP retrieves the email from the email server but also leaves a copy of it on the remote server.
3) SMTP stands for simple mail transfer protocol. This protocol deals with sending an email to an email server.

Question 23

L3
1) What is a wireless access point?
2) What is a router?
3) What is a switch?

Answer 23

1) A wireless access point (WAP) connects to a wired network and provides a wireless network radio signal for wireless devices to connect to. The WAP does not provide internet access, it only provides wireless access to the network.
2) Routers move data from one network to another. Routers are usually used to connect a network to the internet. A wireless access point and a router are both needed to connect to the internet.
3) A switch is needed if there are multiple wired connections on the network. The switch is responsible for connecting data to the correct wired device. A switch is only required if there are wired devices on the network.

Question 24

L3
1) Explain what a hub is
2) Explain what a network interface card is
3) Explain what a bridge is

Answer 24

1) A hub can be used to connect multiple wired devices together. A hub will take any incoming data and broadcast (copy and send) it to all other devices connected to the hub. There are potential security risks with a hub because the data is broadcast to all devices instead of the specific device that needs it.
2) A network interface card (NIC) enables a wired network connection between a computer and another networked device. Every network interface card has a unique address called a MAC address, which is used to locate devices on the network. MAC stands for media access control.
3) A bridge is used to connect a LAN to another LAN. A bridge helps to reduce the traffic in a network by segmenting the network. Data will only pass through the bridge to the other segment or LAN if it is required by that part of the network.

Question 25

L11/12
1) What is malicious software?
2) What is DDoS?
3) What is pharming?

Answer 25

1) Malicious software (malware) is software that is designed to cause harm to a network. Types of attack include:
- Distributed denial of service attacks (DDoS)
- Pharming
- Viruses
- Trojans
2) A distributed denial of service attack (DDoS) is when a server gets flooded with traffic in order to overwhelm it and disrupt the service. This can cause the website to load more slowly or even stop it being accessed at all.
3) A pharming attack is when malware redirects the victim to a malicious version of a website.

Question 26

L11/12
Explain the methods used to protect a network (state 6)

Answer 26

It is important that users are trained to identify potential signs of attack.
Network administrators can give users different levels of access to the network. Users should only have the level of access that they need to perform their role.
There are many other ways to protect a network. These include:
- Anti-malware software
- Firewalls
- Penetration testing
- Physical security
- Backup and recovery

Question 27

L10
1) Explain the application layer
2) Explain the transport layer

Answer 27

1) This is the first step in the TCP/IP model. The application layer provides network services to applications. It also decodes data received so that it can be viewed by the end user.
2) This is the second step in the TCP/IP model. The transport layer checks if the data needs to be broken down into segments. If so, it performs this operation. Once the data has been divided into segments, a header is added with information about the protocol used (either TCP or UDP) and the sender and receiver port numbers.

Question 28

L10
1) Explain the internet layer
2) Explain the link layer

Answer 28

1) This is the third step in the TCP/IP model. The internet layer deals with the IP protocol. It uses this to create IP packets from the data passed into it from the transport layer. The IP packet has a header that lists the sender and receiver IP addresses.
2) This is the last step in the TCP/IP model. The link layer deals with the physical transmission of the data. It creates frames from the IP packets passed to it from the internet layer. These frames include a header that lists the protocol used for the technology that is used from the current node to the next node on the network. It also lists the destination MAC address.

Question 29

L3
1) Define malware
2) Define viruses
3) Define worms

Answer 29

1) Malware (malicious software) is software that is designed to gain access to your computer with malicious intent.
2) Viruses are a malicious form of self-replicating software. Once on a computer or network, a virus will replicate itself by maliciously modifying other computer programs and inserting code.
3) Worms replicate themselves, but do not attach themselves to files. Instead, worms spread through the network and use the system’s resources.

Question 30

L3
1) Define adware
2) Define exploit
3) What is a data breach?

Answer 30

1) Adware refers to software that has advertisements embedded in the application. It is not always a bad thing and is considered a legitimate alternative offered to consumers who do not wish to pay for software.
2) An exploit is code that takes advantage of a system, application, or any other software code.
3) A data breach is a security incident in which sensitive, protected, or confidential data is copied, transmitted, viewed, stolen, or used by an individual who is not authorised to do so. It is also known as data interception.

Question 31

L4
1) What is encryption?
2) What is an encryption key?
3) What is asymmetric encryption?

Answer 31

1) Encryption is the process of encoding data or a message so that it cannot be understood by anyone other than its intended recipient
2) An encryption key is a piece of information, usually random characters, used by a software algorithm to encrypt data or a message into a form that is unreadable (encryption) and allow the data or message to be made readable again (decryption)
3) Asymmetric encryption that uses two keys: a public key and a private key.

Question 32

L4
1) What is symmetric encryption?
2) What is modular testing?
3) What is input sanitation?

Answer 32

1) Symmetric encryption, uses just one key to hide and read a message.
2) Modular testing is testing that checks individual subprograms, subroutines, classes, or procedures in a program.
3) Input sanitation is including code that removes any SQL commands from the input data, preventing a hacker from gaining control of a database.

Question 33

L5
1) What is a firewall?
2) What is packet filtering?
3) What is proxy service?

Answer 33

1) A firewall sits between a local network or computer and another network, controlling the incoming and outgoing network traffic.
2) Packet filtering: packets (small chunks of data) are analysed against a set of filters. Packets that make it through the filters are sent to the requesting system, and all others are discarded.
3) Proxy service: information from the internet is retrieved by the firewall and then sent to the requesting system, and vice versa.

Question 34

L5
1) What is an archiving policy?
2) What is a network policy?
3) What is a disaster recovery policy?

Answer 34

1) A policy that determines how long data can be kept for.
2) A network policy usually contains both an archiving policy and an acceptable use policy.
3) A policy that allows an organisation to resume business quickly during or after a disaster, which could include a cyberattack.

Question 35

L6
1) What is penetration testing (pen test)?
2) What are network forensics?
3) What is the white box pen test?

Answer 35

1) Penetration testing is a type of security testing that is used to test for insecure areas of a system or application.
2) The monitoring and analysis of computer network traffic for information gathering and intrusion detection.
3) Testing in which the tester has full knowledge — more like a malicious insider.

Question 36

L4
1) What are are code reviews?
2) Explain how hacking can occur through the use of passwords
3) What is two factor authentication?

Answer 36

1) Plans to review and test code in an attempt to discover vulnerabilities in programs before cybercriminals find them.
2) Hackers have databases of commonly used or poor passwords that they can use as part of a brute-force attack. A weak password makes it easy for someone to guess your login details.
3) 2FA is an additional layer of security you can add to many of your online accounts.
2FA methods might include being sent a unique code via text message or email. Alternatively, you might have to provide biometrics, such as a fingerprint.

Question 37

L4
How do you create a table in SQL?

Answer 37

CREATE TABLE tablename
(column1 datatype,
column2 datatype,
column3 datatype);
- The name of the table is ‘tablename’
- The title of each field is ‘column’
The tablename cannot have a space.

Question 38

L3
1) Explain how the WHERE cause works
2) Explain the BETWEEN SQL queries
3) Explain the LIKE SQL queries

Answer 38

1) - The WHERE clause is used to select only records satisfying a specified condition:
SELECT FirstName, Surname
FROM members
WHERE Town = ‘Ipswich’

• You can use the following operators in SQL queries:
  = != > < >= <= AND, OR, NOT
  eg. SELECT *
  FROM members
  WHERE Town = ‘Colchester’ OR Town = ‘Ipswich’

SELECT FirstName, Surname
FROM members
WHERE (Town = ‘Colchester’ OR Town = ‘Ipswich’) AND Gender = ‘F’

2) BETWEEN - between an inclusive range
SELECT * FROM Products
WHERE Price BETWEEN 10 AND 20
DateOfBirth BETWEEN #01/01/2018#
AND #31/12/2019#

3) LIKE - search for a pattern
For example:
SELECT *
FROM members
WHERE Surname LIKE ‘H*’
This selects all members whose surname begins with H
Note the wildcard * in the LIKE string which acts as a substitute for zero, one or more characters

Question 39

1) Explain the ORDER BY keyword
2) Explain the UPDATE keyword

Answer 39

1) - ORDER BY allows a query to sort data by ascending or descending order
- For ascending order SELECT * FROM members
ORDER BY Surname ASC
- For descending order SELECT * FROM members ORDER BY Surname DESC
2) - Data stored in records can be changed
- More than one record can be changed at a time
- UPDATE Dogs SET Age = 4 WHERE Age = 3

Question 40

Explain how the INSERT keyword works

Answer 40

• We can INSERT a record into a table
• We do not need to provide a value for an Autonumber field as this will be done automatically
• If the value is a foreign key it will have to be provided
• INSERT INTO Dogs (Dogs.Name, Dogs.Breed, Dogs.Colour, Dogs.Gender, Dogs.Age) VALUES (‘Timmy’, ‘Retriever’,’Green’,’M’,2)