Explain the role of an operating system. Describe memory management and process management. Differentiate between CLI and GUI.

Here are the solutions to the questions: QUESTION 4 (i) a) An operating system (OS) is software that manages computer hardware and software resources and provides common services for computer programs. It acts as an intermediary between the user and the computer hardware. Examples: Microsoft Windows, macOS. b) Two functions of an operating system: • Memory Management: The OS manages the primary memory (RAM) by allocating memory to processes when they need it and deallocating it when they are done. This ensures efficient use of memory and prevents conflicts between programs. • Process Management: The OS handles the creation, scheduling, and termination of processes (running programs). It allocates CPU time to different processes, ensuring that multiple programs can run concurrently. c) Two differences between CLI and GUI: • Interaction Method: A Command Line Interface (CLI) uses text-based commands typed by the user to interact with the system, while a Graphical User Interface (GUI) uses visual elements like icons, windows, and menus that users interact with using a mouse or touch. • Ease of Use: GUIs are generally considered more user-friendly and intuitive for beginners due to their visual nature, whereas CLIs require users to remember specific commands and syntax, making them more suitable for experienced users or specific tasks. d) Two job scheduling techniques: • First-Come, First-Served (FCFS): Processes are executed in the order they arrive in the ready queue. It is a non-pre-emptive scheduling technique. • Shortest Job Next (SJN) / Shortest Job First (SJF): The process with the smallest execution time is selected for execution next. It can be pre-emptive (if a new shorter job arrives while another is running) or non-pre-emptive (if the current job runs to completion). (ii) a) Simplex and full duplex • Simplex: Data flows in only one direction. The sender can only send, and the receiver can only receive. Example: Traditional radio broadcasting (radio station transmits, listeners only receive). • Full Duplex: Data can flow in both directions simultaneously. Both parties can send and receive at the same time. Example: Telephone conversation (both parties can talk and listen at the same time). b) Serial and parallel transmissions • Serial Transmission: Data bits are sent one after another over a single channel. Example: USB connections, Ethernet. • Parallel Transmission: Multiple data bits are sent simultaneously over multiple channels (wires). Example: Older printer cables (Centronics port), internal computer buses. c) Synchronous and asynchronous transmissions • Synchronous Transmission: Data is sent in blocks (frames) with a synchronized clock signal shared between sender and receiver. This allows for continuous data flow without start/stop bits for each byte. Example: Ethernet, ATM networks. • Asynchronous Transmission: Data is sent character by character, with each character framed by start and stop bits. There is no shared clock signal; synchronization is achieved per character. Example: RS-232 serial ports, modems. (iii) a) Prototyping is an iterative software development approach where a preliminary version of the software (a prototype) is built quickly, tested, and then refined based on user feedback. b) Two reasons for prototyping: • Early User Feedback: It allows users to interact with a working model of the system early in the development cycle, helping to identify requirements and design flaws before significant investment is made. • Reduced Development Risk: By validating requirements and design early, prototyping helps to reduce the risk of building the wrong system or encountering major issues late in the development process. QUESTION 5 (i) a) An information system is a set of interrelated components that collect, process, store, and distribute information to support decision-making, coordination, control, analysis, and visualization in an organization. b) Two main components of a basic information system: • Hardware (e.g., computers, servers, network devices) • Software (e.g., operating systems, application programs) c) Three factors that determine the reliability of an information system: • Accuracy of Data: The correctness and precision of the data processed and stored. • System Availability: The percentage of time the system is operational and accessible to users. • Security Measures: The effectiveness of controls in protecting the system and data from unauthorized access, use, disclosure, disruption, modification, or destruction. d) Data validation is the process of ensuring that data is accurate, consistent, and adheres to certain rules or constraints before it is stored or processed. It checks the quality of the data itself. Data verification is the process of checking that data entered into a system matches the original source data. It checks the accuracy of data entry. (ii) a) A primary key is a column or a set of columns in a relational database table that uniquely identifies each row (record) in that table. It must contain unique values and cannot contain NULL values. b) A relational database is a type of database that stores and provides access to data points that are related to one another. It organizes data into one or more tables (or "relations") of rows and columns, with relationships between tables established through primary and foreign keys. c) A Database Management System (DBMS) is a software system that allows users to define, create, maintain, and control access to the database. It provides an interface for users and applications to interact with the database. d) Redundancy in a database refers to the duplication of data, where the same piece of data is stored in multiple places within the database. While sometimes intentional for backup, it often leads to inefficiencies, increased storage space, and potential data inconsistencies. (iii) a) Computer ergonomics is the science of designing and arranging workplaces, products, and systems so that they fit the people who use them. Its goal is to optimize human well-being and overall system performance, especially in the context of computer use. b) Two physical health problems related to the use of computers: • Repetitive Strain Injury (RSI): This is an umbrella term for pain and discomfort in muscles, tendons, and nerves caused by repetitive tasks, forceful exertions, vibrations, mechanical compression, or sustained awkward positions. It often affects the hands, wrists, arms, neck, and shoulders. • Computer Vision Syndrome (CVS): Also known as digital eye strain, this refers to a group of eye- and vision-related problems that result from prolonged computer, tablet, e-reader, and cell phone use. Symptoms include eyestrain, headaches, blurred vision, and dry eyes. c) Two possible ways of avoiding each of the problems stated in (b): • Avoiding RSI: 1. Use an ergonomic keyboard and mouse that support natural hand and wrist positions. 2. Take regular breaks (e.g., 5-10 minutes every hour) to stretch and move around, reducing prolonged static postures. • Avoiding CVS: 1. Follow the 20-20-20 rule: Every 20 minutes, look at something 20 feet away for at least 20 seconds to relax eye muscles. 2. Ensure proper lighting in the workspace to reduce glare and contrast on the screen, and adjust screen brightness to match ambient light. QUESTION 6 (i) a) Pilot running: A new system is introduced in a small part of the organization (e.g., one department or branch) while the old system continues to operate for the rest. Once successful, it's rolled out to other areas. Advantage: Lower risk as problems are contained to a small group, and the system can be refined before wider deployment. b) Parallel running: Both the old and new systems operate simultaneously for a period. Outputs from both systems are compared to ensure the new system is working correctly. Advantage: High security as the old system acts as a complete backup, ensuring business continuity even if the new system fails. c) Direct changeover (or Big Bang): The old system is immediately replaced by the new system on a specific date. There is no overlap between the two systems. Advantage: Cost-effective as it avoids the expense of running two systems simultaneously and is the fastest method of implementation. d) Phased implementation: The new system is introduced in stages or modules over time. Each module is implemented and tested before the next one is introduced. Advantage: Allows for gradual learning and adaptation by users, as they are introduced to parts of the new system incrementally. (ii) a) The objective of the algorithm is to calculate a value for 'x' based on whether an input integer 'n' is even or odd, and then print 'x'. If 'n' is even, x = 3 + n. If 'n' is odd, x = -2 + n. b) Deduce the value of x when n=7: Step 1: input n = 7 Step 2: Is n (7) even? No, 7 is odd. Step 4: else (since n is not even) Step 5: x = -2 + n = -2 + 7 = 5 Step 6: print x The value of x is 5. c) Flowchart of the algorithm: `mermaid graph TD A[Start] --> B(Input n) B --> CIs n even? C -- Yes --> D[x = 3 + n] C -- No --> E[x = -2 + n] D --> F(Print x) E --> F F --> G[Stop] ` (iii) a) The THREE main sub-components of the processor (CPU) and their functions: • Arithmetic Logic Unit (ALU): Performs all arithmetic operations (addition, subtraction, multiplication, division) and logical operations (AND, OR, NOT, XOR) on data. • Control Unit (CU): Manages and coordinates all the components of the computer system. It fetches instructions from memory, decodes them, and directs the operations of the ALU, registers, and other components. • Registers: Small, high-speed storage locations within the CPU that temporarily hold data and instructions during processing. They are used to quickly access data that the CPU is currently working on. b) Volatile memory requires power to maintain the stored information. When the power is turned off, the data is lost. Non-volatile memory retains the stored information even when not powered. The key difference is that volatile memory loses its contents when power is removed, while non-volatile memory retains its contents without power. c) The four stages of the machine cycle in order of operation: 1. Fetch: The Control Unit retrieves an instruction from main memory. 2. Decode: The instruction is translated into commands that the CPU can understand. 3. Execute: The ALU performs the operation specified by the instruction. 4. Store (or Write-back): The results of the execution are written back to registers or main memory.