Computer Science Lecture Notes PDF

Modern Academy FOR Computer Science & Management Technology in Maadi Department of Computer Science Subject: (CS 101) Introduction to Computer Science Professors: Prof. Mahmoud Gadallah, and Dr. Mohamed Elnabawy...

Modern Academy FOR Computer Science & Management Technology in Maadi Department of Computer Science Subject: (CS 101) Introduction to Computer Science Professors: Prof. Mahmoud Gadallah, and Dr. Mohamed Elnabawy Tutorial and Lab Coordinator: Instructor Teams CONTACT: ( LMS-MOODLE) & (WhatsApp: 01005586337). E-Mail: [email protected] COURSE RULES: GRADES/ LATE HW/ ATTENDANCE. CS 101 Dr. Mohamed M. Elnabawy Fall 2025  What is the computer? ❖The term computer is derived from the word compute; that is, to calculate. ❖A computer is … a programmable, electronic device that accepts data (input), performs operations on that data (Processing), and stores the data (Storage) or results (output) as needed. Thus, these are a computer’s basic operations. ❖Computers follow instructions, called programs, which determine the tasks the computer will perform. Four primary operations of a computer  Computer basics ❖In a computer, most processing takes place in a component called the Central Processing Unit or CPU. ❖ The CPU of most modern computers is a microprocessor, which is an electronic component that can be programmed to perform tasks based on data it receives.  Computer basics ❖Memory is an area of a computer that temporarily holds data waiting to be processed, stored, or output. ❖Storage is the area where data can be left on a permanent basis when it is not immediately needed for processing. ❖File is a named collection of data that exists on a storage medium, such as a hard disk, CD, DVD, or flash drive.  Computer basics ❖ A Computer Program is a series of instructions that tells a computer how to carry out processing tasks. ❖These programs form the software that sets up a computer to do a specific task. ❖ When a computer “ runs” software, it performs the instructions to carry out a task. Computer basics  Architecture Components The basic components of a computer system are: 1. Hardware. Processes data by executing instructions Provides input and output 2. Software. Instructions executed by the system 3. Data. Fundamental representation of facts and observations 4. Communications. Sharing data and processing among different systems 5. People ware. Software engineers, programmers, users, computer professionals, system analysts, etc.  Hardware Component The hardware is the physical parts of a computer, The main hardware components are: 1. Input/output devices 2. Storage Devices 3. CPU ALU: arithmetic/logic unit CU: control unit Interface unit 4. Memory Short-term storage for CPU calculations 5. Communication devices  Typical Personal Computer System The following Figure illustrates the basic hardware components of a personal computer. 1. Scanner 2. CPU (Microprocessor) 3. Memory (RAM) 4. Expansion cards (graphics cards, etc.) 5. Power supply 6. Optical disc drive 7. Storage (Hard disk or SSD) 8. Motherboard 9. Speakers 10. Monitor 11. System software 12. Application software 13. Keyboard 14. Mouse 15. External hard disk 16. Printer  Hardware Component CPU: Central Processing Unit The central Processing unit (CPU) consists of the following components: 1. ALU: arithmetic/logic unit Performs arithmetic and Boolean logical calculations 2. CU: control unit Controls processing of instructions Controls movement of data within the CPU 3. Interface unit Moves instructions and data between the CPU and other hardware components 4. Bus: bundle of wires that carry signals and power between different components  Hardware Component Memory Also known as primary storage, working storage, and RAM (random access memory) Consists of bits, each of which holds a value of either 0 or 1 (8 bits = 1 byte) Holds both instructions and data of a computer program (stored program concept)  Types of computer systems Computers are classified into eight categories, according to physical size, processing power, Functions, and price. Supercomputers Mainframes Minicomputers (midrange servers) Workstations Microcomputers (personal computers) Embedded computers Servers Quantum Computers  Types of computer systems Supercomputers Supercomputers are the most powerful computers in performance, processing speed, and capacity. They are also among the fastest computers in the world. Because of their features, supercomputers can tackle complex tasks and compute-intensive problems that just would not be practical for other computers.  Types of computer systems Supercomputers Characteristics: ❖ Massive processing power: Can perform quadrillions of calculations per second. ❖ Parallel Processing: Uses thousands or millions of processors working simultaneously on different parts of a problem. ❖ Large Storage: Equipped with vast amounts of memory and storage to handle huge datasets. ❖ Custom-built: Often designed for specific purposes and custom-built for institutions like NASA or research labs. Applications: Climate research and weather forecasting Genetic sequencing and protein folding simulations Nuclear simulations Artificial Intelligence (AI) research  Types of computer systems Mainframes Mainframe computers are large, powerful systems, and expensive computers designed to handle massive amounts of data, high-volume transactions, and simultaneously processing data for hundreds or thousands of users. mainframes are generally used by businesses or governments to provide centralized storage, processing, and management for large amounts of data.  Types of computer systems Mainframes Characteristics: ❖ High scalability: Can support thousands of users and applications simultaneously. ❖ Centralized processing: Typically housed in data centers and used for mission- critical operations. ❖ High security and reliability: Designed for maximum uptime and security. ❖ Backward compatibility: Can run older software for decades without needing an upgrade. Applications: Financial transactions (banks, credit card companies) Insurance claims processing Government databases and census Airline reservations systems  Types of computer Minicomputers (midrange servers) systems Minicomputers are smaller than mainframes but more powerful than personal computers, minicomputers are used for tasks that require moderate computing power. Often used in manufacturing processes, research labs, and small to medium-sized businesses.  Types of computer Minicomputers (midrange servers) systems Characteristics: ❖ Moderate power: Serve multiple users or smaller tasks but on a lesser scale than mainframes. ❖ Multi-user system: Can handle multiple users and tasks at once, often for departmental applications or small business use. ❖ Cost-effective: More affordable than mainframes and supercomputers, ideal for businesses with less demanding computing needs. ❖ Multi-usage: Often used for database management, web hosting, and application serving. Applications: Scientific labs and research institutions Small business server systems Departmental servers in large organizations  Types of computer systems Workstations Workstations are high-performance single-user computers designed for technical or scientific applications. They are used by engineers, architects, graphic designers, and video editors for tasks like 3D rendering, CAD, and video production.  Types of computer systems Workstations The term workstation has two meanings: It can simply refer to an ordinary personal computer that is connected to a network. A second meaning refers to powerful desktop computers used for high-performance tasks, such as medical imaging and computer-aided design, that require a lot of processing speed.  Types of computer systems Workstations Characteristics: ❖ High-performance components: Equipped with powerful CPUs, GPUs, and large amounts of RAM. ❖ Graphics optimization: Often have professional-grade graphics cards for rendering 3D models or visual effects. ❖ Multi-tasking capability: Designed to handle complex computational tasks while running multiple applications simultaneously. ❖ Expandability: Can be upgraded with additional storage, RAM, and specialized hardware. Applications: Computer-aided design (CAD) Animation and video editing Scientific simulations and data analysis  Types of computer systems Microcomputers (personal computers) Microcomputers, commonly referred to as personal computers (PCs), are designed for individual users for general-purpose tasks like word processing, internet browsing, gaming, and multimedia. Characteristics: ❖ Affordable: Cost-effective and available for personal or business use. ❖ Variety of types: Includes desktops, laptops, and tablets.  Types of computer systems Microcomputers (personal computers) Characteristics Cont’: ❖ Limited multi-user capability: Primarily designed for individual use, although some PCs can serve as small servers. ❖ Portable versions: Laptops and tablets are portable versions of microcomputers. Applications: Office work (word processing, spreadsheets) Media consumption (movies, music) Gaming Internet browsing and communication  Types of computer systems Embedded computers It is a tiny computer embedded into a product designed to perform specific tasks or functions for that product. A microcontroller is a special-purpose microprocessor that is built into the machine it controls. Sometimes, it is called a computer-on-a-chip or an embedded computer because it includes many of the elements common to computers.  Types of computer systems Embedded computers Characteristics: ❖ Task-specific: Designed to perform specific control functions rather than general-purpose computing. ❖ Real-time operation: Often must operate in real-time, controlling processes with precise timing. ❖ Highly reliable and efficient: Optimized for low power consumption and high reliability. ❖ Integration: Embedded in the hardware of larger systems and usually not visible to users. Applications: Automotive systems (engine control units) Consumer electronics (microwave ovens, smart TVs) Medical devices (pacemakers, MRI machines) Industrial machines and robotics  Types of computer systems Server The term Server has several meanings. It can refer to computer hardware, to a specific type of software, or to a combination of hardware and software. The purpose of a server is to serve computers on a network (such as the internet or a home network) by supplying them with data. Any software or digital device, such as a computer, that requests data from a server is referred to as a client.  Types of computer systems Server Any personal computer, workstation, mainframe, or supercomputer can be configured to perform the work of the server. Server does not require a specific type of hardware. however, computer manufacturers such as IBM, SGI, HP, and Dell offer devices called servers that are especially suited for storing and distributing data on a network  Types of computer systems Server Characteristics: ❖ Dedicated roles: Specialized for tasks like file storage, application hosting, or managing databases. ❖ Continuous operation: Servers are expected to operate 24/7 with minimal downtime. ❖ Scalability: Can serve many users simultaneously, ranging from small to enterprise levels. ❖ Remote access: Typically accessed remotely by users on the same network or over the internet. Applications: Web hosting (serving websites) Database management (enterprise resource planning systems) File storage and sharing (cloud storage systems) Email hosting  Types of computer systems Quantum Computers Characteristics: ❖ Quantum bits (qubits): Unlike classical bits, which are either 0 or 1, qubits can exist in multiple states at once. ❖ Massive parallelism: Can process a vast number of possibilities simultaneously. ❖ Cryogenic cooling: Require extremely low temperatures to maintain quantum states. ❖ High error rates: Currently, quantum computers are prone to errors and require significant error correction Applications: Cryptography (factoring large numbers, breaking encryption) Complex simulations (molecular biology, materials science) Optimization problems (logistics, supply chains) AI and machine learning advancements  Starting the Computer The step-by-step booting process: 1. The BIOS (basic input/output system) and setup program. 2. The power-on-self-test (POST). 1. The operating system loads. 2. System configuration. 3. System utilities load. 4. Users Authenticated. The Master Boot Record (MBR) is the information in the first sector of a hard disk or a removable drive. It identifies how and where the system's operating system (OS) is located in order to be booted (loaded) into the computer's main storage or random access memory (RAM). The MBR also includes a program that reads the boot sector record of the partition containing the OS to be booted. In turn, that record contains a program that loads the rest of the OS into RAM.  Starting the Computer Step 1: The BIOS and Setup Program ROM (read only memory): Permanent and unchanging memory BIOS (basic input/output system): The part of the system software that includes the instructions that the computer uses to accept input and output Load: To transfer from a storage device to memory, ROM loads BIOS into the computer’s memory. Setup program: A special program containing settings that control the computer’s hardware, the program can be accessed while the BIOS information is visible.  Starting the Computer Step 2: The Power-On-Self-Test (POST) POST (power-on-self-test): A series of tests conducted on the computer’s main memory (random access memory or RAM), input/output devices, disk drives, and the hard disk. BIOS conducts a Power-On-Self-Test (POST): to check the input/output system for operability. The Master Boot Record (MBR) is the information in the first sector of a hard disk or a removable drive. It identifies how and where the system's operating system (OS) is located in order to be booted (loaded) into the computer's main storage or random access memory (RAM). The MBR also includes a program that reads the boot sector record of the partition containing the OS to be booted. In turn, that record contains a program that loads the rest of the OS into RAM. The computer: will produce a beeping sound and an error message will appear on the monitor if any problems are encountered.  Starting the Computer Step 3: The Operating System (OS) Loads BIOS: searches for the OS. Settings in the CMOS (complementary metal oxide semiconductor): determine where to look for the OS. The operating system’s kernel: is loaded into the computer’s memory. The OS: takes control of the computer and begins loading system configuration information.  Starting the Computer Step 4: System Configuration Registry: A database that stores information about peripherals and software. Peripheral: Device connected to a computer. Driver: A utility program that makes peripheral devices function properly. The system: is configured from the operating system’s registry. Configuration: Drivers are loaded into memory.  Starting the Computer Step 5: System Utilities Loads System utilities are loaded into memory. Volume control. Antivirus software. PC card unplugging utility.  Starting the Computer Step 6: Users Authentication Authentication or user login occurs. ▪ User name ▪ Password The user interface starts, enabling user interaction with computer programs.  Exercises (2) What is a computer? What is Computer Science? What’s the difference between data and information? Mention 3 computer science Fields. Define informatics and mention 5 applied fields for it. Compare between different types of computers. Discuss the steps involved in booting the operating system on your PC.  QR Code for Google Drive link to access Lectures  Thanks CS 101 Dr. Mohamed M. Elnabawy 40 Fall 2025