Content Area 7: Digital Environments

Rate each point. Be honest: 'Secure' means you could answer an exam question on it now without notes.

7.1.1	Explain the features and uses of personal computers, mobile devices, servers and embedded devices
7.1.2	Explain input/output devices, processors (cores, clock speed, cache, mobile), RAM and ROM, secondary storage, motherboard, GPU, network interfaces, cooling and sensors
7.2.1	Explain batch, multitasking, real-time, network and mobile operating systems
7.2.2	Explain file management, defragmenters, compression, package managers, protection and backup utilities
7.2.3	Explain IDEs (editing, debugging, screen design tools), compilers and interpreters
7.2.4	Explain word processors, spreadsheets, databases, email and project management software
7.3.1–2	Explain the benefits and drawbacks of networks and the features of PAN, LAN, MAN, WAN and VPN
7.3.3–4	Compare copper, fibre and wireless connections; star, mesh and tree topologies; logical vs physical
7.3.5–6	Compare client-server, thin client and peer-to-peer; explain the role of servers, clients, routers, switches and the internet backbone
7.3.7–8	Describe the layers, functions and protocols of the OSI and TCP/IP models
7.3.9	Explain packet structure, packet switching, causes of packet loss and CRC
7.3.10	Explain HTTP/HTTPS, SMTP/POP/IMAP, RIP/OSPF, FTP/SFTP, DHCP and DNS
7.3.11	Explain bandwidth and latency and their effect on performance
7.4.1–2	Explain virtual machines, type 1 and type 2 hypervisors, and the key features of virtual environments
7.4.3–4	Explain the benefits and drawbacks of virtual environments
7.5.1–2	Explain private and public cloud and the benefits of cloud
7.5.3	Explain IaaS, PaaS and SaaS, including who manages what
7.6.1	Explain the benefits of resilient environments
7.6.2	Explain methods to improve resilience: updates, hardware replacement, redundancy, hardening, backups, hot/warm/cold sites, standard operating procedures

Types of physical computer (7.1.1)

Type	Features	Typical uses
Personal computer (desktop, laptop)	General purpose; keyboard, mouse, screen; upgradeable (desktops); moderate power use	Office work, software development, gaming, design
Mobile devices (smartphones, tablets)	Portable, battery powered, touchscreen, built-in sensors (GPS, camera, accelerometer), mobile processors, wireless connectivity	Communication, apps, mobile payments, field work (e.g. delivery drivers)
Servers	Powerful multi-core processors, large RAM and storage, redundant power supplies and drives, run 24/7, often rack-mounted, no screen needed	Hosting websites, databases, email, file storage, virtual machines
Embedded devices	Built into a larger product, one dedicated function, low power, often a microcontroller with firmware in ROM, little or no user interface	Washing machines, car engine management, smart thermostats, medical devices

Hardware devices (7.1.2)

Component	Key points
Input devices	Send data into the computer: keyboard, mouse, touchscreen, microphone, scanner, barcode reader, webcam.
Output devices	Present results: monitor, printer, speakers, projector, actuators (motors in robots).
Processor: number of cores	Each core can process instructions independently. More cores help multitasking and programs written to run in parallel. Doubling cores does not double speed if software is not designed for it.
Processor: clock speed	Cycles per second in GHz (3.5 GHz = 3.5 billion cycles per second). Higher speed means more instructions per second but more heat and power.
Processor: cache size	Very fast memory inside the CPU (levels L1, L2, L3). Larger cache means fewer slow trips to RAM.
Processor: mobile processors	Designed for low power and low heat to save battery (e.g. ARM-based). Often a system on a chip (SoC) combining CPU, GPU and other components.
RAM	Volatile. Holds the OS, programs and data in use. More RAM lets more programs run at once without slowing down (less use of virtual memory).
ROM	Non-volatile. Holds firmware such as the BIOS/UEFI used to start the computer. Contents are not normally changed.
Secondary storage: magnetic	Hard disk drives (HDD): spinning platters and a moving read/write head. Cheap per GB, large capacity; slower, moving parts can fail if dropped, noisy.
Secondary storage: solid state	SSDs, USB flash drives, SD cards: flash memory, no moving parts. Fast, robust, silent, low power; higher cost per GB, limited write cycles.
Secondary storage: optical	CD, DVD, Blu-ray: read by laser. Cheap, portable, good for distribution and archiving; low capacity, slow, easily scratched, becoming obsolete.
Motherboard	Main circuit board connecting the CPU, RAM, storage, expansion cards and ports, and carrying data between them.
Graphics processing unit (GPU)	Thousands of small cores for parallel processing. Renders graphics; also used for machine learning, video editing and scientific calculations.
Network interface devices	Connect the computer to a network. Can be an internal PCI/PCIe card (fast, permanent, desktops and servers) or a USB adapter (portable, easy to add, may be slower).
Cooling: air	Heat sinks and fans. Cheap and simple; noisier and less effective under heavy load.
Cooling: liquid	Liquid pumped through a block on the CPU/GPU to a radiator. Quieter and more effective for high-performance machines and data centres; more expensive, risk of leaks.
Sensors	Measure the physical world: temperature, light, motion, GPS, accelerometer, fingerprint. Used in phones, IoT devices and embedded systems.

Server

A computer that provides services or resources (files, web pages, email) to other computers on a network.

Core

An independent processing unit within a CPU. More cores means more instructions can be processed at the same time.

Clock speed

The number of instruction cycles a CPU can carry out per second, measured in GHz.

Cache

Small, very fast memory on or near the CPU that stores frequently used instructions and data.

RAM

Random access memory: volatile main memory that holds the programs and data currently in use.

ROM

Read-only memory: non-volatile memory that holds the startup instructions (firmware/BIOS).

Volatile

Loses its contents when the power is switched off.

GPU

Graphics processing unit: a processor with many cores designed for parallel processing of graphics and large calculations.

Embedded device

A computer built into a larger device to perform one dedicated function, e.g. in a washing machine or car.

Operating systems (7.2.1)

Type	Features	Examples of use
Batch	Runs jobs without user interaction; processes high volumes of similar data; jobs scheduled to run at set times (often overnight).	Payroll runs, bank statement printing, end-of-day billing
Multitasking	Concurrent execution of multiple tasks; time-slicing gives each task a turn on the CPU; interrupts let urgent tasks take priority.	Windows, macOS, Linux desktops
Real-time (RTOS)	Responds to inputs within a guaranteed time. Used for monitoring and control and for transaction processing.	Car airbags, aircraft systems, medical monitors, ticket booking (prevents double booking)
Network OS	Resource sharing (files, printers); user management (accounts, permissions); communication between devices.	Windows Server, Linux servers
Mobile	For smartphones and tablets; touch interface; lower processing requirements; designed to increase battery life (e.g. closes background apps).	Android, iOS

Utilities (7.2.2)

Utility	What it does
File management	Create, copy, move, rename, delete and organise files and folders; search; set permissions.
Defragmenter	Rearranges fragmented files on a magnetic hard disk so each file's parts are stored together, reducing read head movement and speeding up access. Not needed (and not recommended) for SSDs.
File compression	Reduces file size (e.g. ZIP) to save storage and speed up transfers. Lossless keeps all data; lossy (JPEG, MP3) removes some.
Package manager	Installs, updates and removes software and its dependencies automatically from a repository, e.g. pip for Python, apt for Linux, winget for Windows.
Protection software	Anti-malware and firewalls: scan for and remove threats, block unauthorised connections.
Backup software	Copies data on a schedule (full, incremental, differential) so it can be restored after loss.

Code development tools (7.2.3)

Tool	Features
IDE: code editing tools	Syntax highlighting, auto-complete, auto-indentation, line numbers, error highlighting as you type, refactoring tools.
IDE: debugging tools	Breakpoints, stepping through code line by line, watching variable values, call stack view.
IDE: screen design tools	Drag-and-drop design of graphical user interfaces (forms, buttons, layouts) that generates the code.
Compiler	Translates the whole program into machine code before it runs, producing an executable. Fast to run; code is hidden from users; errors are reported after compiling the whole program; must recompile for each platform. Examples: C, C++, (C# compiles to an intermediate form).
Interpreter	Translates and runs code one line at a time. Easier debugging (stops at the error line); runs on any platform with the interpreter; slower to run; source code must be distributed. Example: Python.

Application software (7.2.4)

Application	Features and business uses
Word processors	Create and format documents: letters, reports, contracts; templates, mail merge, track changes, collaboration.
Spreadsheets	Calculations with formulas and functions, charts, sorting and filtering data; budgets, sales analysis, forecasts.
Databases	Store large amounts of structured data in tables; queries, forms and reports; customer records, stock control. Reduce duplication compared with spreadsheets.
Email	Send messages and attachments; calendars and contacts; formal written record of communication.
Project management software	Plan tasks, Gantt charts, assign resources, track progress and deadlines, Kanban boards (e.g. Microsoft Project, Trello, Jira).

Operating system

Software that manages hardware and resources and provides a platform for applications.

Time-slicing

Giving each task a short slot of processor time in turn, so several tasks appear to run at once.

Interrupt

A signal to the processor that something needs attention immediately.

Utility

System software that maintains or optimises the computer, e.g. backup, compression.

Package manager

A tool that installs, updates and removes software and its dependencies, e.g. pip, apt.

IDE

Integrated development environment: software that combines a code editor, debugger and other tools for programming.

Compiler

Translates the whole source code into machine code in one go, producing an executable file.

Interpreter

Translates and runs source code one line at a time.

Benefits and drawbacks of networks (7.3.1)

Benefits	Drawbacks
Share files and data; collaborate Share hardware such as printers and internet connection Central backup and security management Communication: email, messaging, video Users can log in from any machine Software can be installed and updated centrally	Cost of hardware (servers, switches, cabling) and specialist staff Malware and attacks can spread across the network If a server or switch fails, many users are affected Performance slows with heavy traffic Needs ongoing management and security

Features of network types (7.3.2)

Networks differ in number of users, connection media (the cables or wireless used) and coverage (the area served).

Type	Coverage	Example	Notes
PAN: personal area network	A few metres around one person	Phone connected to smartwatch and earbuds by Bluetooth	Very few devices; low power
LAN: local area network	One building or site	A college or office network	Owned and managed by the organisation; fast; Ethernet and Wi-Fi
MAN: metropolitan area network	A town or city	A council linking its offices and libraries; city-wide Wi-Fi	Often uses fibre leased from telecoms providers
WAN: wide area network	Countries or the world	The internet; a bank linking branches nationally	Uses third-party infrastructure; slower and more expensive than LAN
VPN: virtual private network	Any distance, over the internet	Staff connecting securely to the office network from home	Creates an encrypted tunnel over a public network so traffic can't be read

Connectivity methods (7.3.3)

Method	Features	Benefits	Drawbacks
Copper / Ethernet (twisted pair, e.g. Cat 6)	Electrical signals; up to 100 m per run	Cheap; reliable; fast (1–10 Gbps); easy to install	Interference (EMI); limited distance; signal degrades
Fibre-optic	Pulses of light through glass or plastic	Very high bandwidth; long distances; immune to electrical interference; hard to tap	Expensive; fragile; specialist installation
Wireless access points (Wi-Fi)	Radio waves; WAP connects wireless devices to the wired network	Mobility; no cables; easy to add devices	Slower and less reliable than cable; range limited by walls; interference; must be secured (WPA3)

Topologies (7.3.4)

Topology	Layout	Benefits	Drawbacks
Star	Every device connects to a central switch.	One cable failure only affects one device; easy to add devices; good performance	If the central switch fails, the whole network fails; lots of cable
Mesh	Devices connect to many others (full mesh: every device to every other).	Very resilient: many routes for data; no single point of failure	Expensive and complex; lots of connections. Partial mesh reduces this. Used in WANs and the internet backbone, and wireless mesh home Wi-Fi.
Tree	Several star networks connected in a hierarchy from a root.	Scalable; easy to manage in sections (e.g. one star per floor)	If the root or a backbone link fails, the sections below are cut off

Physical topology is how devices are actually cabled. Logical topology is how data actually flows. For example, a network can be physically wired as a star but data may be passed in a logical bus or ring pattern; Wi-Fi devices have no cables but logically form a star around the access point.

Network models (7.3.5)

Model	How it works	Benefits	Drawbacks
Client-server	Clients request services from central servers that store data and manage security.	Central backup and security; easy to manage users; scalable	Servers are expensive; needs IT staff; server failure affects everyone
Thin client	Clients have minimal processing power and storage; the server does almost all processing (e.g. virtual desktops).	Cheap clients; easy to manage centrally; data never stored on the client so more secure	Totally dependent on the server and network; poor for heavy graphics
Peer-to-peer	All computers are equal and share resources directly; no central server.	Cheap; easy to set up; no single point of failure	No central backup or security; harder to manage as it grows; performance depends on each peer

Network components (7.3.6)

Component	Role
Server	Provides services to clients: files, web pages, email, authentication, printing.
Client	A device that requests and uses services from a server.
Router	Connects different networks (e.g. a LAN to the internet) and forwards packets towards their destination using IP addresses. Home routers often include a switch, WAP and firewall.
Network switch	Connects devices within a LAN; learns MAC addresses and sends data only to the intended device, reducing unnecessary traffic.
Internet connection / backbone	The connection to an ISP; the backbone is the high-capacity fibre network of main routes that carries internet traffic between countries and providers.

Topology

The arrangement of devices and connections in a network.

Router

Forwards data packets between different networks using IP addresses.

Switch

Connects devices within a LAN and forwards data only to the device it is addressed to, using MAC addresses.

Layered models split networking into separate layers. Each layer has a job and passes data to the layer above or below. Benefits: hardware and software from different vendors work together; one layer can change without affecting the others; easier to troubleshoot.

OSI layer	Function	Example protocols / devices	TCP/IP layer
7 Application	Provides network services to applications the user interacts with.	HTTP, HTTPS, FTP, SMTP, POP, IMAP, DNS, DHCP	Application
6 Presentation	Formats, encrypts and compresses data so it can be understood by the receiver.	TLS/SSL encryption, JPEG, ASCII, MP4	Application
5 Session	Opens, manages and closes communication sessions between devices.	NetBIOS, RPC, session handling in TLS	Application
4 Transport	Splits data into segments, end-to-end delivery, error checking, flow control, port numbers.	TCP (reliable, ordered), UDP (fast, no guarantee)	Transport
3 Network	Logical (IP) addressing and routing packets between networks.	IP, ICMP, RIP, OSPF; routers	Internet
2 Data link	Physical (MAC) addressing, framing, error detection on the local link.	Ethernet, Wi-Fi (802.11) frames, ARP; switches	Network (access)
1 Physical	Transmits raw bits as electrical, light or radio signals.	Cables, connectors, radio frequencies; hubs, NICs	Network (access)

TCP/IP layer	Function	Protocols
Application	Combines OSI 5–7. Provides services to applications and formats data.	HTTP, HTTPS, FTP, SFTP, SMTP, POP, IMAP, DNS, DHCP
Transport	Establishes end-to-end connections, splits data into numbered segments, uses ports, handles retransmission.	TCP, UDP
Internet	Adds source and destination IP addresses and routes packets across networks.	IP (IPv4, IPv6), ICMP
Network (access / link)	Combines OSI 1–2. Sends frames over the physical medium using MAC addresses.	Ethernet, Wi-Fi, ARP

Practise: which OSI layer?

Protocol

A set of rules that govern how data is transmitted and received.

Data packets (7.3.9)

Part	Contents	Role
Header	Source IP address; destination IP address; packet sequence number; total number of packets; protocol; time to live (TTL)	Gets the packet to the right place and lets the receiver reassemble packets in order. TTL stops lost packets circulating forever.
Payload	The actual data being sent (a chunk of the file, email or web page)	The content.
Trailer	Error-checking value (e.g. CRC) and end-of-packet marker	Lets the receiver detect whether the packet was corrupted.

Packet switching

1. Data is split into packets, each with a header.
2. Each packet is sent independently; routers forward each one along the best available route at that moment.
3. Packets may take different routes and arrive out of order.
4. The receiver uses the sequence numbers to reassemble them.
5. Missing or corrupted packets are requested again (TCP).

Benefits: efficient use of the network; routes around failures and congestion. Drawbacks: packets can arrive out of order or be delayed, which matters for real-time traffic like video calls.

Causes of packet loss

• Network congestion: routers' buffers fill up and packets are dropped.
• Faulty or damaged hardware (cables, routers, NICs).
• Wireless interference or weak signal.
• TTL reaching zero before arrival.
• Software bugs or misconfigured devices; deliberate attacks such as DoS.

Error handling: cyclic redundancy check (CRC)

1. The sender performs a calculation (a form of polynomial division) on the packet's data to produce a CRC value.
2. The CRC value is added to the trailer.
3. The receiver performs the same calculation on the data it received.
4. If the values match, the data is accepted. If not, the packet is corrupt and is discarded and re-requested.

Network protocols (7.3.10)

Protocol	Purpose	Port (useful to know)
HTTP	HyperText Transfer Protocol: requests and transfers web pages between browser and web server. Not encrypted.	80
HTTPS	HTTP Secure: HTTP encrypted with TLS, so data such as passwords and card numbers cannot be read if intercepted; server identity verified with a certificate.	443
SMTP	Simple Mail Transfer Protocol: sends email from client to server and between mail servers.	25 / 587
POP (POP3)	Post Office Protocol: downloads email from the server to one device, usually deleting it from the server. Good for one device and offline access.	110
IMAP	Internet Message Access Protocol: email stays on the server and is synchronised across all devices.	143
RIP	Routing Information Protocol: routers share routes and choose the path with the fewest hops (max 15). Simple; suited to small networks; slow to adapt.	-
OSPF	Open Shortest Path First: routers share link-state information and calculate the fastest path based on cost (e.g. bandwidth). Scales to large networks; adapts quickly to changes.	-
FTP	File Transfer Protocol: uploads and downloads files between client and server. Not encrypted.	20 / 21
SFTP	SSH File Transfer Protocol: secure, encrypted file transfer.	22
DHCP	Dynamic Host Configuration Protocol: automatically gives devices an IP address, subnet mask, default gateway and DNS server when they join a network.	67 / 68
DNS	Domain Name System: translates domain names (wakefield.ac.uk) into IP addresses.	53

Practise: which protocol?

Bandwidth and latency (7.3.11)

	Bandwidth	Latency
Meaning	The maximum amount of data that can be transferred per second	The delay for data to travel from sender to receiver
Unit	Bits per second (Mbps, Gbps)	Milliseconds (ms)
Affected by	Connection type, number of users sharing it, ISP package	Distance, number of hops/routers, congestion, connection type (satellite is high)
Effect when poor	Slow downloads and uploads, video buffering, low quality streams	Lag in online games and video calls, slow response to clicks, even if downloads are fast

Try it: download time calculator

Packet

A small unit of data sent across a network, containing a header, payload and trailer.

Packet switching

Splitting data into packets that travel independently across a network and are reassembled at the destination.

CRC

Cyclic redundancy check: an error-detection value calculated from the packet's data and checked by the receiver.

Bandwidth

The maximum amount of data that can be transferred per second, measured in bits per second.

Latency

The time delay for data to travel from source to destination, measured in milliseconds.

Components (7.4.1)

Component	Role and characteristics
Virtual machine: clients	Virtual PCs (a full desktop OS running as software), virtual switches (connect VMs to each other and to the physical network), virtual routers (route traffic between virtual networks).
Virtual machine: servers	Several virtual servers (web, database, email) run on one physical server, each with its own OS, isolated from the others.
Hypervisor: type 1 (bare metal)	Runs directly on the hardware with no host OS. Efficient, secure, high performance. Used in data centres. Examples: VMware ESXi, Microsoft Hyper-V, Proxmox.
Hypervisor: type 2 (hosted)	Runs as an application on a host OS. Easy to install; slower because it goes through the host OS. Used for testing and learning. Examples: VirtualBox, VMware Workstation.

Key features (7.4.2)

Feature	Meaning
Increased security	VMs are separated, so malware in one VM does not easily spread to others or the host; snapshots allow quick recovery.
Managed execution	The hypervisor controls each VM's access to resources (CPU, RAM, storage), so VMs run in a controlled way.
Sharing	Several VMs share one set of physical hardware.
Aggregation	Resources from several physical machines are combined to act as one larger pool (e.g. a cluster).
Emulation	A VM can imitate different hardware or an older OS, so legacy software can still run.
Isolation	Each VM is independent: a crash in one does not affect the others.
Portability	A VM is stored as files, so it can be copied, backed up or moved to another host easily.

Benefits and drawbacks (7.4.3–7.4.4)

Benefits

Drawbacks

Cost effective for large environments: fewer physical servers, less space, power and cooling Easy management: VMs created, cloned and monitored from one console Resilience: VMs can move to another host if one fails Potentially lower carbon footprint: fewer machines running Improved disaster recovery: VM files can be backed up and restored quickly Better testing environments: test software on different OSs safely; roll back with snapshots Education and training: students can practise on VMs without damaging real systems

Extra hardware load: the hypervisor uses resources, and the host needs plenty of RAM and CPU Slower execution time than running directly on hardware Potential for false representation of performance: software tested in a VM may perform differently on real hardware If the physical host fails, all its VMs go down unless failover is set up

Virtual machine (VM)

A software-based computer that runs an operating system and applications like a physical machine.

Hypervisor

Software that creates and runs virtual machines and shares physical hardware between them.

Types of cloud (7.5.1)

	Private cloud	Public cloud
Meaning	Cloud infrastructure used by one organisation only, on its own premises or hosted by a provider.	Infrastructure owned by a provider and shared by many customers over the internet.
Examples	A bank's own data centre running virtualised services	AWS, Microsoft Azure, Google Cloud
Benefits	Full control; greater security and privacy; can meet strict regulations	No upfront hardware cost; pay as you go; scales easily; provider handles maintenance
Drawbacks	Expensive to build and maintain; needs skilled staff; limited scalability	Less control; data held by a third party (possibly abroad); depends on internet connection; costs can grow

Benefits of cloud (7.5.2)

Benefit	Meaning
Portability	Access services and data from any device, anywhere with internet; move workloads between environments.
Elasticity	Resources scale up automatically at busy times and down when quiet, e.g. an online shop on Black Friday.
Fewer storage limitations	Storage can be increased on demand without buying hardware.
Cost effectiveness	No upfront hardware purchase; pay only for what is used; fewer IT staff needed for maintenance.

Delivery models (7.5.3)

Layer	On-premises	IaaS	PaaS	SaaS
User accounts	Client	Client	Client	Client
Data	Client	Client	Client	Client
Application software	Client	Client	Client	Provider
Runtime	Client	Client	Provider	Provider
System software (middleware and OS)	Client	Client	Provider	Provider
Virtualisation	Client	Provider	Provider	Provider
Hardware (servers, network, storage)	Client	Provider	Provider	Provider

Model	Example	Advantages	Disadvantages	Suits
IaaS	AWS EC2, Azure Virtual Machines	Most control and flexibility; no hardware to buy	Client must manage and secure OS and software; needs skilled staff	IT teams who need custom servers
PaaS	Azure App Service, Google App Engine, Heroku	Developers focus on code; no OS patching; quick deployment	Less control; limited to supported languages/tools; vendor lock-in	Software developers building and deploying apps
SaaS	Microsoft 365, Google Workspace, Salesforce	Ready to use; no installation; provider handles everything	Least control and customisation; data held by provider; subscription costs continue	End users and businesses needing standard software

Practise: who is responsible?

Elasticity

The ability of cloud resources to scale up or down automatically to match demand.

IaaS

Infrastructure as a Service: the provider supplies virtualised hardware; the client manages everything from the OS up.

PaaS

Platform as a Service: the provider supplies hardware, OS and runtime; the client manages applications and data.

SaaS

Software as a Service: the provider supplies the complete application; the client manages users and data.

Benefits of resilience (7.6.1)

Benefit	Impact on organisation and clients
Increased security: data security in storage and transfer; reduced vulnerabilities	Data is protected from loss and attack; fewer weaknesses for attackers to exploit.
Increased reputation: protect brand/image; retain customer confidence	Customers trust an organisation whose services are reliable and whose data is safe.
Reduction in downtime	Services stay available, so sales, productivity and customer service continue.

Methods to improve resilience (7.6.2)

Method	Detail
Software updates / upgrades	Planned updates and upgrades on a schedule (tested first, outside busy hours). Patches released quickly in response to new vulnerabilities.
Hardware replacement	Rolling replacement plans: replace a proportion of hardware each year so nothing becomes too old and costs are spread. Secure disposal: wipe or physically destroy drives so data cannot be recovered; use certified recyclers.
Data and system redundancy	Duplicate components so one failure doesn't stop the service: RAID disks, spare power supplies, UPS, backup internet connection, duplicate servers with failover, data replicated to another site.
Device hardening	Remove unneeded ports, applications, permissions and access; change default passwords; disable unused services. Fewer ways in for attackers.
Backup systems and recovery procedures	Onsite: fast to restore but at risk from the same fire or theft. Remote/offsite: protected from local disasters but slower to restore. Cloud: automatic, offsite, scalable; depends on internet and provider. Recovery procedures must be documented and tested.
Hot, warm and cold sites	Alternative locations to continue operating after a disaster (table below).
Standard operating procedures	Written step-by-step procedures so tasks are done consistently and safely: effective staff training; induction for new staff; procedures for new digital systems; procedures for new or updated policies.

Site	What it has	Time to recover	Cost
Hot	Fully equipped, running systems with real-time or near real-time copies of data	Minutes to hours	Highest
Warm	Hardware and network connections in place; data must be restored from backup	Hours to days	Medium
Cold	Space, power and cooling only; equipment must be brought in and set up	Days to weeks	Lowest

Redundancy

Having duplicate components or data so that if one fails, another takes over.

Device hardening

Reducing a device's attack surface by removing unneeded ports, applications, permissions and access.

Hot site

A fully equipped backup site with up-to-date data that can take over almost immediately.

Cold site

A backup location with power and space but no equipment or data set up.

Standard operating procedure (SOP)

A written, step-by-step instruction for carrying out a routine task consistently.

Flashcards

Every Quick recall definition on this page. Click the card to flip it; use the arrow keys to move.

Random questions on CA7 from the course question bank. Pick a topic or question type, answer in your head or on paper, then check. Your score is saved on this device.

Allow about 100 minutes.

My corrections: what I need to go back over