ICT Notes By MR. Lukhele 1.0 Types and components of a computer computer system is a programmable electronic device that can accept input; store data; and retrieve, process and output information. Example of a computer system. 1.2 Hardware and software A computer system consists of two main or key components which are hardware and software. Computer Hardware: Hardware are physical components which makes up a computer system, they include the physical parts of a computer, such as the central processing unit, random access memory, motherboard, computer data storage, graphics card, sound card, and computer case. It includes external devices such as a monitor, mouse, keyboard, and speakers. NB: Hardware can be either internal or external. ❑ There are two categories of hardware namely internal and external.: ➢ Internal hardware: Motherboard • The motherboard is the main circuit board of a computer, connecting all components and allowing them to communicate. • It houses essential parts like the CPU, RAM, storage devices, and expansion cards. • It provides power distribution and data pathways, ensuring the smooth functioning of the system. Random Access Memory (RAM) • RAM is a type of volatile memory that temporarily stores data and instructions that the CPU is actively using. • It helps speed up processing by providing quick access to frequently used programs and files. • More RAM allows a computer to handle multiple tasks efficiently, reducing lag and improving performance. Read-Only Memory (ROM) • ROM is a type of non-volatile memory that stores permanent instructions, such as the computer’s firmware or BIOS (Basic Input/Output System). • It ensures that the computer can start up properly by loading the necessary boot instructions. • Unlike RAM, ROM retains its data even when the computer is turned off. Sound Card • A sound card processes and outputs audio signals, enabling the computer to play sounds, music, and voice recordings. • It improves the quality of audio output and allows connections to external speakers, microphones, and headsets. • Some advanced sound cards support 3D and surround sound, enhancing multimedia and gaming experiences. Internal Storage Devices • • Hard Disk Drive (HDD) • HDDs store the operating system, software, and user data. • They use spinning magnetic disks to read and write data. • Though slower than SSDs, they offer large storage capacities at a lower cost. Solid State Drive (SSD) • SSDs store data using flash memory, making them significantly faster than HDDs. • They improve boot times, reduce loading times for applications, and enhance overall system responsiveness. • SSDs are also more durable because they have no moving parts. External hardware • Keyboard • A keyboard is an input device that allows users to enter text, numbers, and commands into the computer. • Mouse • A mouse is a handheld input device used to control the cursor and interact with graphical user interfaces (GUIs). • Printer • A printer is an output device that produces physical copies of digital documents, images, or text. Software: is a computer program that provides a set of instructions to execute a user’s commands and tell the computer what to do. For example, like the Microsoft office suite which includes MSWord, MS-Excel, PowerPoint. NB: You need software in order for the computer to operate effectively. It is a collection of data that is given to the computer to complete a particular task. two main categories of software are application software, and system software. Both of these are important for the particular task to be performed. Two main categories of software • Application software: is type of software which performs specific functions for the user. It assists the user in doing specific tasks on the computer system. • Examples: ❑ Word processor: normally used to manipulates texts documents for instance, reports or essay. Functions of word processor: ➢ Creating, editing, saving and manipulating text ➢ Spell checkers and importing photos/images ➢ Translation of other languages ❑ spreadsheet software: is normally used for organizing and manipulating numerical data. Functions of spreadsheet software ➢ Use of formulars to carry out calculations. ➢ It can be used to produce graphs. ➢ It can be used to do modelling. ❑ Apps (Applications): these are types of software which runs on mobile phones and tablets, they are downloaded. Types of Apps includes, Web apps, Native apps, Hybrid apps, Desktop apps, Mobile apps, ❑ Database software: this is a type of software that is used to organize, manipulate and analyses data. Normally a database is made up of one or more tables with each table consisting of rows and columns where each row called a record and each column is called a field. ❑ video editing software: this is a software that allows a user to manipulate videos to produce an edited video, interms of color of the picture, adding sound to the original video. ❑ Graphical manipulation software: it allows bitmap and vector images to be changed. • System software • System software: is a type of computer software designed to run a computer's hardware and application programs. Examples of system software: Operating system: is an essentially software running in the background of a computer system. It enhances human-computer-interaction (HCI), input/output operations, error handling, loading and running of programs to occur, managing of security ❑ Utilities software: this are software that has been designed to carry out specific task on a computer. They assist in managing, maintaining and controlling computer resources. These include: antivirus, anti-spyware, backup of files, disk repair, file management, security, screen saver, disk defragmenter. ❑ Device driver: this is a software that enable one or more hardware devices to communicate with the computer’s operating system. Every hardware device connected to a computer have associated drivers, this includes: memory sticks, mouse, CD drives…etc. ❑ Compiler: this is a computer program that translates a program written in high-level language (HLL) into machine code (code that is understood by the computer). High-level languages include Java, Python, Visual Basic, Fortran, C++ and Algol. 1.3 Main components of a computer system ❑ CPU - Central Processing Unit is the most important part of a computer which interprets and executes the command from the computer hardware and software. It is part of the computer motherboard. However, due to modern manufacturing techniques, the term microprocessor is now used instead of CPU. This is a single IC which is at the heart of most PCs and is also found in many household (appliances) devices and equipment where some control or monitoring is needed. E.g., Fridge, TV, Washing Machine, car, calculator, CPU can be subdivided into a control unit, which controls the input and output devices; an arithmetic logic unit (ALU), which carries out calculations and makes logical decisions ❑ RAM – RAM is an internal chip where data is temporarily stored when running apps. This memory can be written to and read from since its contents are lost when power is switched off. It is also known as volatile or temporary memory. ❑ ROM – ROM is a memory used to store information that needs to be permanent. It is often used to contain, for example, configuration data for computer system. These chips cannot be altered and only be read from. It contains some coding known as the boot file. This code tells the computer what to do when it first starts up, it is often referred as BIOS (Basic Input Output System). ❑ HDD/SSD - The internal hard disk drive (HDD) or solid-State drive (SDD) is the main internal storage of a computer where the operating system and application software as well as users’ data, files, etc. are stored. The main advantage of these drives is the fast transfer/access times and their large capacity to store data. 1.4 Operating system • Operating system is system software that manages computer hardware and software resources. • It provides a user interface and enables interaction between the user and the computer Functions of the Operating System • Resource Management: The operating system manages and allocates memory, CPU time, and other hardware resources among the various programs and processes running on the computer. • Process Management: The operating system is responsible for starting, stopping, and managing processes and programs. It also controls the scheduling of processes and allocates resources to them. • Memory Management: The operating system manages the computer’s primary memory and provides mechanisms for optimizing memory usage. • User Interface: The operating system provides a user interface that enables users to interact with the computer system. • Security: The operating system provides a secure environment for the user, applications, and data by implementing security policies and mechanisms such as access controls and encryption User interfaces This is the means by which users and a computer system interact, normally through the use of input devices and software, It is also known as a point of huma-computer interaction and communication in a device, how the user interacts with an application using visual and audio elements Types of user interface ❑ Command line interface (CLI): is a console or text-based representation in which the user types commands into a computer to operate and navigate the software or interact with a computer system. It normally uses a keyboard for text input of commands that are required to navigate the computer. The advantages of CLI are that user is in direct communication with the computer and is not restricted to predetermined options. Example of a command: cd for changing a directory, copy for copies files, del for deleting files. Advantages 1. The user is not restricted to a set of predetermined options. 2. The user directly communicates with the computer. 3. It allows the user to alter the computer's configuration settings. Disadvantages 1. The user must learn a number of commands to carry basic tasks/operations. 2. All commands must be typed in, which is time consuming and also prone to errors. 3. Each command must be entered using correct format, spelling, etc. 4. It is very difficult to edit once the commands have been typed. Users • The main users of the CLI command are generally programmers, technicians or system operators who need to directly communicate with the computer to develop a new software, locate bugs, errors and remove or fix them, initiate memory/system dumps to identify the errors, etc. ❑ Graphical user interface: is a type of user interface which allows a user to interacts with a computer through graphical icons and visual indicators. Here a user can interact with a software using clickable icons. • It is more common and user-friendly One of the most common keys windows, icons, menus and pointing device (WIMP) which was developed for use on personal PCs. This uses a mouse to control a cursor which then selects icons to open or run windows. • In recent years, devices such as touch screen phones use post WIMP interaction where fingers are in contact with the screen. This allows actions such as pinching and rotating which would be difficult to do using a single pointing device such as a mouse. Advantages 1. It is user-friendly as icons are used to represent applications. 2. There is no need for the user to learn any commands. 3. As a pointing device which is generally a mouse is used to click on an application icon, to launch the application, it is easier and simpler than typing in commands. Disadvantages 1. The number of applications a user can use is limited to the number of icons shown on the screen. 2. It uses hugely more computer memory than that used by CLI interface. 3. It needs a high-level operating system like Windows to operate resulting in consumption of higher amount of memory. Users Being a simple to use interface, the users are generally people who may not have any or little knowledge as to how the computer works or a person who uses the computer only to execute a software or check mails, etc. 1.5 Types of computers ❑ PC/Desktop • It refers to a general-purpose computer which is made of separate monitor, keyboard, mouse and processor unit. The term PC usually refers to computer systems which are IBM compatible thus distinguishing them from Macintosh machines. Example of desktop. Advantages 1. Spare parts and connections are generally standardized resulting in low cost of maintenance. 2. Desktops have better specifications (faster processors) for a given price. 3. Power consumption is not of a concern as they plug directly into a wall socket and the larger casing allows good dissipation of heat that might buildup. 4. Further, as they are fixed in one location, chances of being damaged is minimized. 5. Also, internet access is more stable as they are not moved around resulting in same data transfer rate from the internet. Disadvantages 1. Desktops are not particularly portable since they are made up of separate components. 2. All the components need to be connected by wires which can be quite complex and take more space if they are moved around. Because they are not portable, it is necessary to copy files when you do your work elsewhere Laptop • Laptop or notebook refers to the type of computer where the monitor, keyboard, mouse, processor are all together in a single unit. This makes them extremely portable. The key features are Light weight, low power consumption and Processor which does not generate much heat. • Advantages 1. They are very portable. 2. No trailing wires. 3. Advantages of Wi-Fi. 4. Since they are portable, they link into any multimedia system. Disadvantages 1. They have limited battery life so user needs to carry a heavy adapter. 2. Since they are portable, probability of breakages is high and also easier to steal. 3. Keyboard and pointing devices are awkward to use. 4. Being compact they generate more heat than desktops. Tablets • Tablets are a relatively new invention that are internet-enabled portable computers. They work similar to a smartphone and are touch-screen based without a keyboard though some hybrid of tablets and laptops are also available. Internet access is generally through Wi-Fi or 3G/4G/5G (mobile phone) connectivity or sim cards. They are equipped with sensors like microphones, camera, touch screens, etc. • Advantages of tablets compared to laptops 1. Fully portable as they are very light and can be easily carried anywhere. 2. Due to the touch-screen feature, they are very easy to use and do not require any other input devices. 3. Switch on very fast unlike the windows system in laptops. 4. Has many Apps as standard like a built-in camera, speakers, etc. 5. When the power button is pressed, it goes in standby mode, however, it still remains connected to the internet and alerts the user when an email is received or other 'events' happen. 6. As they are using solid state technology, they do not generate any heat. Has much longer battery life than a standard laptop Disadvantages of tablets compared to laptops 1. Typing on a touch screen is cumbersome and is prone to errors when compared with a normal keyboard. 2. They have lesser memory or storage compared to a laptop. 3. They will be expensive to run if internet is accessed frequently over mobile networks. 4. Transferring of files has to be done through Apps store as there is no app to drag and drop files and is cumbersome and irritating for the user. 5. Laptops support more file format types than tablets and also are better equipped to run different types of software. Smartphones • Smartphones have operating systems like Android, iOS or Windows, due to which they can used not only to make phone calls but also allows them to run a number of computer applications called Apps. These allows users to send/receive emails, use the camera to take photos/videos, use payment wallets apps to make utility payments, etc. • Advantages 1. Can be used to make phone calls as well as connect to the internet on the move. 2. Being small in size and lightweight, they are easy to carry around on our person unlike laptops which are much bulkier and also much heavier. 3. As they use Wi-Fi and mobile phone networks, they can be used almost anywhere which is not the case with laptops or PCs, although tablets also use the same technology. 4. They have hundreds of Apps like phone banking, payment wallets, camera facility, etc., which is similar to tablets, but it is advantage over laptops. 5. They have a reasonable battery life compared to laptops. Disadvantages 1. Web browsing and photography drains the battery quickly. 2. Memory size in most phones isn't very large when compared to laptops and PCs, although it is comparable with tablets. 3. Not all website features are compatible with smartphone operating systems. 4. Due to their small size, it is much easier to steal or lose a smartphone compared to laptops and PCs. 5. Small screens make pages difficult to read and the small keyboards make typing things in more difficult and slower than laptops/PCs. However, this disadvantage is becoming less of a problem as smartphones screens get larger on newer phablets. 6. Data transfer rate using mobile phones is slower than with Wi-Fi, which makes streaming of video or music, for example, less than satisfactory at times. Mainframe Computers • The term Mainframe computer is used for large, very powerful computer system. It derives its name from the era when individual components were housed in large frames (often room-sized). • Their primary purpose is to run commercial applications like banking, insurance, manufacturing, etc., where huge amounts of data need to be processed on daily basis. • Their primary purpose is to run commercial applications like banking, insurance, manufacturing, etc., where huge amounts of data need to be processed on daily basis. • ❑ The main features of these computers are: 1. They have very fast processor speeds. 2. They can support multiple operating systems. 3. They can have several CPUs. 4. They have huge amounts of storage capacity. 5. They have huge internal memories running into several hundred gigabytes (GBs) of RAM. 6. They often operate using time sharing or batch processing. 1.7 Impact of emerging technologies ❑ Robots • Robots have been used for years, mainly in manufacturing. • Perform tasks like welding, painting, and assembling with minimal human effort. • Now used in service industries, military, and research. • Increases efficiency and safety. • Some restaurants use robot waiters for serving food. • Reduces labor costs and improves service. ❑ Computer-Assisted Translation (CAT) helps humans translate texts faster and more accurately. • Used in business, education, and international communication. ❑ Quantum cryptography is a method of securing communication using quantum mechanics. • Provides unbreakable encryption for data security. ❑ 3-D and holographic imaging • Holography is a technology that allows one to make 3-D images known as holograms to be produced. The technology involves the use of: • A source of laser light • Interference of light • Light diffraction and • Light intensity recording • As a holographic image is rotated, it appears to move in the same way as the original object, thus giving a feeling of three dimensions (3-D). The hologram is produced by first splitting a laser beam. Half of the light known as object beam is reflected off the object on to a photographic plate. The other half of the light known as the reference beam is reflected off a mirror and on to the same photographic plate. The holographic image is produced where the two light beams meet on the photographic plate. Holograms have many applications 1. Architecture (ability to rotate design through 360 degrees. 2. Simulations 3. Cinema for special effects 4. Advertising 5. Gaming for special effects Positive impacts of emerging technologies ❑ Improved Communication • Faster and more efficient (e.g., 5G, AI chatbots). ❑ Better Healthcare • AI helps in diagnosis and robotic surgeries. ❑ Increased Automation • Robots and AI reduce human effort in industries. ❑ Enhanced Cybersecurity • Quantum cryptography for secure data protection. ❑ Smarter Education • E-learning, AI tutors, and virtual reality (VR) improve learning experiences. Negative impacts of emerging technologies ❑ Job Losses • Automation replaces human workers in some industries. ❑ Privacy Concerns • AI and IoT collect personal data, raising security issues. ❑ Cyber Threats • More advanced tech leads to stronger hacking techniques. ❑ High Costs • New technology requires heavy investment. ❑ Ethical Issues • AI decisions and biotechnology advancements raise moral concerns.
