OCR Computer Science Paper 1

What is the purpose of systems software?

Software designed to run or maintain a computer

Describe the functionality of systems software.

It controls the operations of computer hardware

What is an operating system?

A piece of software responsible for running the computer, managing hardware, applications, users and resources

What are the 5 things that operating systems are used for?

providing a UI, memory management/multitasking, peripheral management and drivers, user management, file management

What is utility software?

Software designed to help maintain a computer system

What is encryption software?

Software used for encrypting data

What is defragmentation software?

Reorganising data on a hard drive to put broken up files back together and collect up the free space

What is data compression?

The process of making the size of a file smaller

Give the 2 types of backup.

full and incremental

What is Hacking?

Illegal access or attack on a computer network or device

What is malware?

Malicious software created to damage or gain illegal access to computer systems

What is Phishing?

When criminals send emails or text to someone claiming to be a well-known business.

Describe social engineering.

A way of gaining illegal access to data or networks by influencing people.

What is a Brute Force Attack?

A network attack which uses software to crack security passwords through trial and error.

What is a Denial of Service attack?

A network attack which stops users from accessing a part of a network or website.

What is data interception and theft?

When data is intercepted when travelling across a network. This can be done through packet sniffing or having a wireless connection.

What is SQL injection?

A piece of SQL code which can be typed into an input box to try and attack the SQL database

Give an example of a poor network policy.

unencrypted data, no user access levels, no passwords, no anti-malware or firewall software

What is penetration testing?

The process of simulating attacks on a network to identify its weaknesses

What does network forensics involve?

monitoring the traffic on a network

What is a network policy?

A set of rules and procedures an organisation will follow to ensure their network is protected against attacks

What is anti-malware software?

Software designed to stop malware from damaging a computer or network

What is a firewall?

Software that limits access to and from a computer system

Describe user access levels.

Controls what files or areas of the network different groups of users can access

How can a password be made secure?

more varied range of characters

What is encryption?

Coding data so that it can only be decoded with the correct key.

Give examples of network topologies.

star, mesh, bus, tree

What is a star network?

A network topology where all devices are connected to a central switch or server which controls the network

What is a mesh network?

A network topology where every device is directly or indirectly connected to every other without a central switch or server

What is Wi-Fi?

The standard used for wireless connections between devices

What is ethernet?

Network protocol used on LANs

What is an IP address?

A unique identifier given to a device when it accesses an IP network

What is a MAC address?

A unique identifier assigned to a device that cannot be changed.

Give the 7 most common protocols

TCP/IP, HTTP, HTTPS, FTP, POP, IMAP, SMTP

Describe the layering system.

groups of protocols that have similar functions

What is the Application layer?

Turning data into websites and other applications and vice versa.

What is the Transport layer?

Controlling data flow- e.g. splitting data into packets and checking packets are correctly sent and delivered.

What is the Internet layer?

Making connections between networks, directing data packets and handling traffic. Used by routers.

What is the Network layer?

Passing data over the physical network. Responsible for how bits are sent as electrical signals over cables, wireless and other hardware.

What is a packet?

Small, equal-sized units of data used to transfer files over networks

What is packet switching?

The process of directing data packets on a network using routers and the IP protocol.

Name 2 types of network.

LAN WAN

What is LAN?

(Local area network) A network which only covers a single site

What is WAN?

(wide area network) A network which connects networks in different geographical locations

Give some factors that might affect the performance of a network.

Bandwidth, number of users, wired connection, hardware, network topology

What is a client-server network?

A type of network managed by a server, which takes requests from client devices

What is a peer-peer network?

A network in which all devices are equal and connect directly to each other

Give 4 required pieces of hardware used to connect standalone computers to a LAN.

WAP, routers/switches, NIC, transmission media

What is the internet?

A worldwide collection of computer networks

Name the 3 computer networks that make up the internet.

DNS, hosting, the cloud

What is DNS?

(domain name server) A server which stores website domain names and their IP addresses

What does hosting mean?

When a business uses its servers to store the files of another organisation

What is the cloud?

The use of the internet to store files and provide software

What is a virtual network?

A software-based network that exists between devices on a physical network

What is secondary storage?

external data storage used to store data so that the computer can be switched off.

Why is capacity important?

To aid in the choice of media

How could you estimate the required capacity?

By adding together the file sizes for all the files that need to be stored.

Name 3 common types of storage.

optical, magnetic, solid state

State the 6 characteristics when choosing suitable storage devices.

capacity, speed, portability, durability, reliability, cost.

What is the difference between RAM and ROM?

RAM is volatile-temporary, ROM is non-volatile- permanent

What is the purpose of ROM in a computer system?

Tells the CPU how to boot up (BIOS)

What is the purpose of RAM in a computer system?

Main memory which stores data, programs and the OS while in use.

What is virtual memory?

A section of the hard disc used as if it were RAM to supplement the amount of main memory available to the computer

What is flash memory?

Very common form of personal portable file storage

Give examples of flash memory.

USB drive, SD card, SSD

What is the purpose of the CPU?

The brain of the computer which processes all data and instructions

Name 4 parts of Von Neumann architecture.

MAR MDR PC Accumulator

What is the MAR?

Holds any memory address about to be used by the CPU

What is the MDR?

Holds actual data or instruction. Either fetched or written to memory

What is the PC?

Holds the memory address of the instruction for each cycle

What is the Accumulator?

Stores intermediate results of calculations in the ALU

Name 3 common CPU components.

CU ALU Cache

What is the function of the ALU?

Does all of the mathematical calculations

What is the function of the CU?

Overall control, controls data, follows FDE cycle

What is Cache?

Very fast memory close to the CPU, stores regular data, cache always checked first

How does the CPU function?

FDE cycle

Name 3 things that affect the performance of a CPU.

Clock speed, cache size, number of cores

What is an embedded system?

Computers that are built into other devices. Control systems, dedicated tasks

Give examples of embedded systems.

Dishwasher, microwave, TV