IT Summary Grade 11

• Hardware: Physical components of a computer system, such as CPU, memory, and peripherals,
providing the infrastructure for computing tasks.
• Software: Non-physical components including programs, data, and instructions, controlling
hardware operation and enabling specific tasks and functions.
• ICT System: A combination of hardware, software, networks, and data that enables the collection,
processing, storage, and communication of information electronically.

CPU design:
Parallel processing is the CPU’s ability to work on multiple tasks at the same time. the CPU to execute
several tasks concurrently, which can significantly increase overall performance and speed. This is
typically achieved through multiple cores or threads within the CPU, each capable of executing
instructions independently.

ALU – Carries out arithmetic and logic operations in the computer

CU - component of a computer processor that coordinates and manages the execution of instructions,
fetching them from memory, decoding them, and controlling the operations of the Arithmetic Logic Unit
(ALU) and other parts of the CPU.

Registers:
Registers in computing are fast, small memory locations within the CPU. They store data being
processed, including instructions, addresses, and intermediate results. Registers facilitate efficient
execution of instructions by providing quick access to data for processing, making them integral to
the CPU's performance.

Primary storage:
BIOS: (Basic Input/Output System) is firmware embedded on a motherboard chip,
responsible for initializing and managing hardware components during the boot-up
process.
RAM: (Random Access Memory) is volatile memory used by the CPU to store data and
instructions for real-time processing, enabling quick access to information by the computer.
Secondary storage:
HDD: (Hard Disk Drive) is a non-volatile storage device used in computers to store and
retrieve digital data magnetically on spinning disks called platters, accessed by
read/write heads, providing high-capacity, relatively low-cost storage for files, programs,
and operating systems.

SSD: (Solid State Drive) is a non-mechanical storage device that uses flash memory to store
data, offering faster read/write speeds and increased durability compared to traditional
HDDs.
Hybrid drive: combines the storage capacity of a traditional HDD with the speed and
responsiveness of an SSD
SD card: SD cards are small, portable, non-volatile memory cards commonly used for
storing digital data in devices such as cameras, smartphones, and tablets.

Difference in performance between CPU and RAM:

• The CPU handles the actual processing and calculations, RAM provides the space for the
CPU to work with data quickly. Both are essential for a computer's performance, and a
balance between CPU power and RAM capacity/speed is necessary for optimal
performance in different tasks and applications.

Speed and Latency:

• Speed refers to how quickly a computer can perform tasks, often measured by the
processing power of the CPU and the data transfer rates of storage devices.
• Latency, on the other hand, is the delay between a request and its completion, such
as the time taken for data to travel between components like RAM, CPU, and storage.
Lower latency means faster response times and smoother performance.

SRAM:
• SRAM, or Static Random Access Memory, is a type of computer memory known for
its speed and stability. Unlike dynamic RAM (DRAM), which requires periodic
refreshing to maintain data, SRAM retains data if power is supplied to the system.
This characteristic makes SRAM faster but also more expensive to produce. SRAM is
commonly used in CPU caches, where it stores frequently accessed data and
instructions, allowing the CPU to access them quickly without having to fetch them
from slower main memory (DRAM). It is also utilized in other high-performance
computing systems and devices where fast and stable memory is essential, such as
networking equipment and disk controllers.

DRAM:
DRAM (Dynamic Random Access Memory) is a type of volatile computer memory that
stores data and program code for quick access. It needs refreshing to maintain data and is
commonly used in RAM modules due to its high density and cost-effectiveness, though it
has slower access times compared to SRAM.
Caching:
Caching is a technique used in computing to improve performance by storing frequently
accessed data in a location that can be accessed more quickly than fetching it from its
original source.
• Processor cache:
Processor caching is like having a small, super-fast memory chip right next to the brain of
your computer (the CPU). This chip stores the most frequently used information and
instructions, like your favorite song or a frequently visited website. So, instead of going all
the way to the main memory (RAM) to get this data, the CPU can quickly grab it from the
cache, saving a lot of time. It's like keeping your most important stuff on your desk rather
than in a filing cabinet across the room, making everything faster and more efficient.
• Disk caching:
A disk cache is a mechanism for improving the time it takes to read or write to a hard disk.
A disk cache can also be a specialized portion of the RAM. The disk cache holds data that's
recently been read.
• Browser cache:
Browser caching is a way for web browsers to store copies of web page resources, such as
HTML files, images, CSS stylesheets, and JavaScript scripts, locally on a user's device. When
you visit a website, your browser downloads these resources to display the page properly.
With caching, instead of fetching these resources from the web server every time you
revisit the same website or navigate to different pages within it, your browser stores copies
of these resources on your device.
• Proxy cache:
Proxy caching is a feature of proxy servers the stores data on the proxy itself. The proxy
server coordinates with the source sever to cache documents such as files, images and web
pages.

Motherboard function and components:

• System clock controls timing of communication between devices
• Clock multiplication is called the “clock ratio,” it is the speed ratio between the
computers frontside bus and the CPU
• Overclocking: increasing the clock speed of a computer component, such as a CPU or
GPU, beyond its factory-set specifications to enhance performance, albeit with
potential risks to stability and longevity.
• The Internal Bus (Front Side Bus) comprises three components: the Data Bus for
transferring data, the Address Bus for specifying memory locations, and the Control
Bus for managing signals. Registers within the CPU utilize these buses to facilitate
data movement and control during instruction execution, contributing to overall
processor operation efficiency.
 • External buses like PCI Express, SATA, and USB differ in speed and throughput. PCI
Express offers high-speed data transfer for expansion cards, SATA provides fast data
transmission for storage devices, while USB offers versatility but typically slower
data transfer rates for various peripherals.

Comparing Primary and Secondary storage:

Primary Memory:
• Registers: Fastest, smallest capacity, located within CPU, used for temporary storage
of data and instructions.
• CPU Cache: Fast access, larger capacity than registers, located closer to CPU, stores
frequently accessed data and instructions.
• RAM: Faster than secondary storage, larger capacity than cache, volatile, used for
temporary storage and active programs/data.
Secondary Storage:
• Flash Memory: Moderate speed, lower bandwidth, moderate capacity, non-volatile,
used in SSDs, USB drives, and memory cards.
• HDD: Slower speed compared to SSD, higher capacity, non-volatile, uses spinning
disks for storage.
• SSD: Faster than HDD, moderate to high capacity, non-volatile, uses NAND flash
memory for storage.
• External Hard Drives: Similar to internal HDD or SSD, used for portable storage with
various capacities.
• Cloud Storage: Speed varies, high bandwidth, virtually unlimited capacity, relies on
remote servers, offers reliability through redundancy and backups.

Processing Techniques:
Software:
• Multitasking: Allows multiple tasks to run concurrently on a single CPU, managed by
the operating system through time-sharing.
• Multi-threading: Divides a single process into multiple threads, enabling concurrent
execution within the same process.
 Hardware:
• Hyper-threading: Simulates multiple logical processors within a single physical CPU
core, improving overall efficiency by allowing the CPU to work on multiple threads
simultaneously.
• Multi-core: Incorporates multiple physical CPU cores on a single chip, enabling
parallel processing of tasks across cores, enhancing overall performance.
• Multiprocessing: utilization of multiple processors or CPU cores within a single
computer system to simultaneously execute multiple tasks or processes, improving
overall performance and efficiency.

Memory, Storage, and IO Management:

• Memory Management: Handles allocation and deallocation of memory resources to
processes, ensuring efficient utilization and preventing conflicts.
• Storage Management: Organizes and manages data storage devices, including
secondary storage like HDDs, SSDs, and cloud storage, ensuring data integrity,
accessibility, and reliability.
• I/O Management: Controls input and output operations between the CPU and
external devices, optimizing data transfer rates, handling interrupts, and managing
device drivers.
Recommendations:
• For software, utilize multitasking and multi-threading techniques to maximize CPU
utilization and improve responsiveness.
• Hardware-wise, consider employing hyper-threading or multi-core processors for
enhanced parallel processing capabilities, depending on workload requirements and
budget constraints.
Machine Cycle:
The machine cycle is the basic operational process that a computer's CPU (Central
Processing Unit) follows to execute instructions. It consists of four main stages: Fetch,
Decode, Execute, and Write Back.
• Fetch: The CPU retrieves (fetches) the next instruction from the computer's memory (RAM)
based on the value stored in the Program Counter (PC), which keeps track of the memory
address of the next instruction to be executed.
• Decode: The fetched instruction is then decoded to determine what operation needs to be
performed and what data is involved. The CPU breaks down the instruction into its
 component parts, such as the opcode (operation code) and any operands (data values)
needed for the operation.
• Execute: In this stage, the CPU performs the actual operation specified by the instruction.
This could involve arithmetic calculations, logical operations, data movement, or other
tasks depending on the instruction. The CPU interacts with other components, such as the
ALU (Arithmetic Logic Unit) and registers, to carry out the instruction.
• Write Back: Finally, if the instruction produced a result that needs to be stored back in
memory or registers, this stage involves writing the result back to the appropriate location
in memory or updating the relevant registers.

UEFI vs BIOS and CMOS interrupts:

UEFI (Unified Extensible Firmware Interface):
• Modern firmware interface replacing BIOS.
• Supports larger storage devices, faster boot times, and advanced features.
• Provides a graphical interface for system configuration.

BIOS (Basic Input/Output System) and CMOS (Complementary Metal-Oxide-

Semiconductor):
• Traditional firmware and low-level hardware initialization.
• CMOS stores BIOS settings.
• BIOS initializes hardware and boots the operating system.
• CMOS interrupts allow for low-level communication and control between hardware
components and the BIOS.
IRQs and IO range:
IRQs (Interrupt Requests):
• Signals sent by hardware devices to the CPU to request attention.
• Used to handle hardware events such as keyboard input or data transfer
completion.
IO Range (Input/Output Range):
• Range of memory addresses reserved for communication between CPU and
peripheral devices.
• Allows devices to send and receive data to and from the CPU.

Virtual Memory:
• Virtual memory is a memory management technique that allows the computer to
compensate for physical RAM shortages by temporarily transferring data from RAM to disk
storage.
• It creates an illusion of having more memory than physically available by utilizing disk
space as an extension of RAM.

Paging:
• Paging is a virtual memory management scheme where the physical memory is divided into
fixed-size blocks called pages.
• When the system runs out of physical memory, it transfers some pages from RAM to disk,
freeing up space for other data.

Swapping:
• Swapping is the process of moving entire processes or pages of memory between RAM and
disk.
• It allows the operating system to manage memory efficiently by temporarily swapping out
less-used data to disk and bringing in more urgently needed data into RAM.

Virtual memory and its effect on speed:

• Virtual memory increases memory capacity but introduces performance overhead
due to data transfer between RAM and disk storage, potentially slowing processing
speed, especially during heavy swapping.

Difference between high level and low level language:

High level language Low level language

Easy to learn and understand Challenging to learn and understand
Execute slower than low level as they Execute with high speed
require a translator program
They allow much more abstraction They allow little or no abstraction
For writing programs, hardware Hardware knowledge is a must
knowledge is not required
Easy to modify Difficult to modify
A single statement may execute several Statements can be directly mapped to
instructions processor instructions
BASIC, Pearl, COBOL, Ruby etc... Machine language and assembly language
 • Compilers: Translate entire source code files into machine code before execution,
resulting in faster execution but longer initial compilation time.
• Interpreters: Execute source code line by line, translating each line into machine
code at runtime, providing faster feedback but potentially slower execution
compared to compilation.
• Assemblers: Translate assembly language source code into machine code, directly
mapping instructions without high-level optimizations, typically used for low-level
programming close to hardware.

E-Communications:
Network:

• A collection of interconnected devices that communicate and share resources.

• Can be local (LAN) or wide-area (WAN).

Client:

• A device or software that requests services or resources from a server.

• Examples include computers, smartphones, and applications.

Server:

• A device or software that provides services or resources to clients.

• Examples include web servers, file servers, and database servers.

Switch:

• A network device that connects multiple devices within a LAN.

• Uses MAC addresses to forward data to the correct destination.

Router:

• A network device that connects different networks and routes data between them.
• Uses IP addresses to determine the best path for data packets.

Firewall:

• A security device or software that monitors and controls incoming and outgoing network traffic.
• Based on predefined security rules, it helps protect networks from unauthorized access and
threats.

Bounded Media:

• Physical transmission media with defined boundaries.

• Examples include twisted pair cables, coaxial cables, and fiber optic cables.

Unbounded Media:
 • Wireless transmission media without physical boundaries.
• Examples include radio waves, microwaves, and infrared signals.

Classification pf networks:

• PAN < LAN < WAN < GAN

Reasons for using networks:

• Communication, sharing resources, centralization, data transfer, productivity

Topology:
Star Topology:

• Advantage: Easy to install and manage; if one device fails, it doesn't affect the rest of the
network.
• Disadvantage: Central hub failure leads to network downtime.

Bus Topology:

• Advantage: Easy to implement and requires less cable than other topologies.
• Disadvantage: A single cable failure can bring down the entire network.

Ring Topology:

• Advantage: Data transmission is relatively simple since data travels in one direction, reducing
collisions.
• Disadvantage: A failure in any single node can disrupt the entire network.

Hybrid Topology:

• Advantage: Combines the benefits of different topologies, providing flexibility and scalability.
• Disadvantage: Can be complex and expensive to design and maintain.

Mesh Topology:

• Advantage: reliable; if one link fails, data can be rerouted through other paths.
• Disadvantage: Expensive and complex to install and maintain due to the large number of
connections(cables).
IPV4 vs IPV6:
• IPv4 and IPv6 are two versions of the Internet Protocol used for routing traffic. IPv4 uses 32-bit
addresses, whereas IPv6 uses 128-bit addresses. IPv4 addresses are written in decimal format
and its headers are simpler but variable in length, while IPv6 addresses are in hexadecimal
format with fixed-length, more complex headers. IPv4 and IPv6 differ significantly in how they
handle DNS, DHCP, and address resolution due to the protocols' design differences. IPv4 uses
"A" records in DNS for address translation, DHCPv4 for dynamic address assignment, and ARP
for mapping IP addresses to MAC addresses. In contrast, IPv6 uses "AAAA" records in DNS to
accommodate its larger address size, employs both DHCPv6. IPv4 uses "A" records in DNS for
address translation, DHCPv4 for dynamic address assignment, and ARP for mapping IP addresses
to MAC addresses. In contrast, IPv6 uses "AAAA" records in DNS to accommodate its larger
address size, employs both DHCPv6.

Broadcast vs point to point communication:

• Broadcast communication sends data to all devices on a network, while point-to-point
communication sends data directly between two specific devices, ensuring privacy and
efficiency.

Ethernet and IP Packet Structure and Network Device Associations:

• Ethernet frames consist of a header (with source and destination MAC addresses), optional
VLAN tag, payload (containing IP packet), and frame check sequence (FCS). IP packets within
Ethernet frames include an IP header (with source and destination IP addresses) and payload.
Switches and bridges operate on Ethernet frames, while routers handle IP packets.
Wireless Access Point, Wireless Bridge and Wireless Router:
Wireless Access Point (WAP):

• Function: Connects wireless devices to a wired network.

• Advantage: Extends wireless network coverage.
• Disadvantage: Requires a wired connection for each access point.
Wireless Bridge:

• Function: Connects two separate network segments wirelessly.

• Advantage: Connects network segments wirelessly without the need for physical cables.
• Disadvantage: Susceptible to interference and requires line-of-sight for optimal performance.
Wireless Router:

• Function: Routes data between networks and provides Wi-Fi connectivity.

• Advantage: Combines routing and wireless access, providing an all-in-one solution for internet
sharing.
• Disadvantage: Limited range may not cover larger areas effectively.

Wired vs Wireless connections in terms of bandwidth and speed:

Wired connections typically provide higher bandwidth and faster speeds than wireless connections, as
they have lower latency, less interference, and more stable signal quality.

WAN components and transmission technologies:

Gateways:

• WiFi Router:
o Connects local networks to the internet.
o Provides wireless connectivity.
o Speeds vary, typically up to several Gbps.

Transmission Technologies:

• Satellite:
o Uses radio waves to communicate with orbiting satellites.
o Suitable for remote areas.
o Wide coverage, high latency (500-600 ms), speeds up to 100 Mbps.
• Microwave:
o Uses line-of-sight radio waves between terrestrial towers.
o Ideal for point-to-point communication.
o high speed (up to several Gbps), low latency, affected by weather.

Transmission Media:
 • Fiber Optic:
o Transmits data via light through glass/plastic fibers.
o High-speed internet and backbone networks.
o Extremely high speeds (up to 100 Gbps), low latency, expensive.
• ADSL:
o Uses copper telephone lines.
o Common for residential internet.
o Speeds up to 24 Mbps, higher latency, widely available.

Speed and Bandwidth Comparison

• Fiber Optic: Up to 100 Gbps, very high bandwidth, low latency.
• ADSL: Up to 24 Mbps, limited bandwidth, higher latency.
• Satellite: Up to 100 Mbps, moderate bandwidth, high latency.
• Microwave: Up to several Gbps, high bandwidth, low to moderate latency.

Comparison of data transmission over the internet:

VOIP (Voice over Internet Protocol)

Function:
• Function: Enables voice communication and multimedia sessions over the internet.
Advantage:
• Cost Savings: Reduces costs for long-distance and international calls.
Disadvantage:
• Dependence on Internet Connection: Quality and reliability depend on the internet connection.

Lossy vs Lossless:

Lossy Compression:
• Function: Reduces file size by permanently eliminating some data, typically non-essential or
imperceptible to human senses.
• Advantage: Achieves significantly smaller file sizes, making it ideal for efficient storage and
transmission.
• Disadvantage: Loss of original data quality, which can be noticeable upon decompression.
Lossless Compression:
• Function: Reduces file size without any loss of data, preserving the original quality upon
decompression.
 • Advantage: Maintains exact fidelity of the original data, crucial for applications where quality
preservation is paramount.
• Disadvantage: Generally achieves smaller reductions in file size compared to lossy compression
methods.
Data Protection:

Threats:

Hardware failure/ power failure/ Malware – ransomware(malicious software that encrypts files on a
victim's computer, demanding payment (usually in cryptocurrency) for decryption)., phishing (online
scam where attackers pretend to be trustworthy sources, like banks or companies, to trick people into
giving away sensitive information such as passwords or credit card numbers.), virus, spyware,
pharming, spoofing (person or program disguises its identity to impersonate another entity or gain
unauthorized access to data or systems).

Solutions:

RAID 1 to 5:

• RAID 1 (Mirroring): Data is duplicated across two or more disks. Offers redundancy and
improved read performance, but requires double the storage capacity.
• RAID 2: Uses bit-level striping with dedicated Hamming code parity. Rarely used due to
complexity and inefficiency.
• RAID 3: Uses byte-level striping with dedicated parity disk. Offers good performance for
large sequential transfers, but limited by parity disk bottleneck.
• RAID 4: Similar to RAID 3 but uses block-level striping. Parity is stored on a dedicated
disk. Good for applications with large random reads.
• RAID 5: Uses block-level striping with distributed parity across all disks. Offers good
performance and fault tolerance with improved storage efficiency compared to RAID 1.

UPS and Redundant Power Supplies:

• UPS (Uninterruptible Power Supply): Provides backup power during electrical outages
or fluctuations, ensuring continuous operation of devices and preventing data loss or
damage.
• Redundant Power Supplies: Ensures continuous operation by using multiple power
supply units. If one fails, others take over seamlessly, minimizing downtime and
ensuring reliability in critical systems.