Operation System & Networks

What does OS stand for?

Operating System

Operating System (definition)

Essential software that manages computer hardware, coordinates basic system operations, and provides services for running application software e.g. Linux. Windows

Name the functions of an operating system (6)

Resource management. Process management. User Interface. Multitasking. File Management. Security

How do operating systems perform resource management?

Allocates and monitors CPU and memory usage

How do operating systems perform process management?

Manages the lifecycle of all running programs

How do operating systems contribute to user interface?

Provide tools and environments for user interaction

How do operating systems allow multitasking

Allow the operation or multiple programs at once

How do operating systems allow for file management?

They organize. Store. Retrieve files and directories.

How do operating systems allow for security

Controls access and permissions for users and software.

Draw the layer model of an operating system

…

Explain the layer model of an operating system

User interacts with the application program. Application programs carry out specific tasks e.g. Microsoft Word. Application program interacts with OS which controls how the application program interacts with the hardware

LAN (definition)

(Local Area Network) Covers a small area like a building. E.g. Loreto Kilkenny.

WAN (definition)

(Wide Area Network) Spans large geographical areas. Utilises external infrastructure e.g. telecommunications (internet)

Client-Server (definition)

Centralised server manages resources

Describe a client-server model

Computer makes a request which arrives at the server. Server carries out request and the information e.g. webpage is transmitted to the computer (client)

Advantages of client-server

Security. Scalability

What is scalability?

The ability of hardware or software to continue to function when put under pressure e.g. more users, tasks, data

Disadvantages of client-server networks

Single point of failure

What is a peer-to-peer network?

All devices act as both client and server.

Advantages of peer-to-peer

Simple. Low cost

Disadvantages of peer-to-peer

Poor security

NIC (definition)

(Network Interface Card) Allows devices to connect to a network

Router (definition)

Forwards data between networks e.g. LAN to WAN

Switch (definition)

Connecte devices within a network, intelligent data packet routing.

What does Hyper Text Protocol stand for?

Hypertext Transfer Protocol

What layer is HTTP?

Application

What is the purpose of HTTP?

Deliver web pages over the internet

What does HTTPS stand for?

Hypertext Transfer Protocol Secure

What layer is HTTPS?

Application

Function of HTTPS

Securely deliver web pages over the internet

What does TCP stand for?

Transmission Control Protocol

What layer is TCP?

Transport

Function of TCP

Provide Reliable. Ordered. Error-checked delivery of a stream of data

What does IP stand for?

Internet Protocol,

What layer is IP?

Network

Function of IP

Handle the addressing and routing of data packets

What layer is TCP/IP?

Network

Function of TCP/IP

Communicate over the internet using combinations of protocols

What layer is Wi-Fi?

Physical

Function of Wi-Fi

Connect devices to the internet wirelessly

What does VoIP stand for?

Voice over Internet Protocol

What layer is VoIP?

Application

Function of VoIP

Enable voice communication over the internet

What does FTP stand for?

File Transfer Protocol

What layer is FTP?

Application

Function of FTP

Transfer files from one host to another

What is an IP address?

A unique string of numbers (IPv4 or IPv6) that identifies each device connected to a network which enables data to be sent and received accurately e.g. 192.168.1.1

What is dynamic IP?

Changes with each connection

What is static IP?

Permanent

Data packets (definition)

Data sent across the internet is split into small packets

Structure of Data Packets

Header (source/destination). Data. Error check

What is packet switching?

When a packet takes a different route to reach their destination (sequence number)

What does TCP do to packets?

Splits data into packets and reassembles them

What does IP do to packets?

Routes packets to the correct destination

What kind of format does IPv4 use?

32-bit format

What kind of format does IPv6 use? Why is it used?

128-bit. More combinations to accommodate the growing up number of devices on the internet.

MAC Address (definition)

A hardware identification number that uniquely identifies each device on a network. It is assigned to the network interface card (NIC) by the manufacturer and used for network communication within the local network segment.

WWW (World Wide Web) (definition)

Collection of websites accessible via the internet

Firewalls can be … firewalls or … firewalls

Hardware. Software

Firewalls (definition)

Control data entering and leaving a network based on security rules, acting as a barrier between trusted internal networks and untrusted external ones like the internet.

How does a firewall protect?

Filtering and blocking unauthorised access and cyber threats.

Encryption (definition)

Ensures data is securely transmitted e.g. HTTPS

What does DNS stand for?

Domain Name System

DNS (function)

Looks for the address of a website. A DNS checks other DNSs for a website address if they don’t have it.

What does SSL stand for?

Safe Sockets Layer

What does TLS stand for?

Transport Layer Security

Function of SSL

Encrypts websites

Function of TLS

Encrypts communication between websites

What does it mean when a web application is obsolete?

Works perfectly, but it’s out of date

What does URL stand for?

Uniform Resource Locator

Function of URL

Address of websites

What is a GET Request?

Computer requests to receive a webpage from a server

What is a POST request?

You send information e.g. Logging in. Cookies Data

What is a Cookie ID?

Everyone assigned a number (cookie ID). App uses it to remember you.

Bandwidth (definition)

The maximum transmission capacity of a device

Bit Rate (definition)

Number of bits that we can send over a given period of time.

What is a fibre optic cable? (Compsci)

Thread of glass engineered to reflect light

Fibre optic cable VS. Ethernet cable (Fibre optic cable) (4)

Light signals. Expensive. Signal doesn’t degrade over long distances. Multiple signals can use 1 cable

Fibre optic cable VS. Ethernet cable (Ethernet cable) (3)

Digital signals. Cheap. Used in LAN as signals degrade over relatively short distances

Why are static IP addresses used for servers? (2)

Ensures constant access. Prevents conflicts

Why are dynamic IP addresses used for personal devices? (2)

Ensures flexibility. Efficient use of addresses