Computer Science Unit 1: Intro to Computer Systems

Study Notes

Basic Computer Organization: Includes hardware (input, output, CPU, primary and secondary memory, units like bit, byte, KB, MB, GB, TB, PB), and software (system software like OS, system utilities, device drivers; application software).
Types of Software: System software (OS, utilities, device drivers) manages the computer, while application software performs specific tasks. Language translators (assembler, compiler, interpreter) convert higher-level programming languages into machine code.
Operating System (OS): Manages the computer's resources, providing an interface between hardware and software. Includes various functions like process management, memory management, file management, device management, security, and user interface.
Boolean Logic: NOT, AND, OR, NAND, NOR, XOR logical operations and their truth tables are fundamental for computer logic. De Morgan's laws are useful conversions for logical expressions.
Number Systems: Binary, octal, decimal, and hexadecimal are used to represent data in computers. Conversion between these systems is important.
Encoding Schemes: ASCII, ISCII, and Unicode (UTF8, UTF32) represent characters as numbers in a computer's memory.

A computer is an electronic device programmed to accept input, process it, and generate output.
A computer system comprises the computer and additional hardware and software.

500 BC: Abacus, a mechanical device for simple calculations.
1642: Pascaline (mechanical calculator) for addition and subtraction.
1834: Analytical Engine (mechanical computer), a precursor to modern computers.
1890: Tabulating machine (Herman Hollerith)—an important step towards computing.
1937: Turing Machine concept—a general-purpose programmable computer model.
1945: EDVAC/ENIAC: Stored program computers (John Von Neumann).
1947: Transistor developed, replacing vacuum tubes—drastically reduced computer size and power consumption.
1970: Integrated circuits (ICs) containing entire electronic circuits on a single chip—further miniaturisation and reduced cost.

Architecture of a computer involving Central Processing Unit (CPU), memory, input, output, and their communication channels.
Electronic Numerical Integrator and Computer (ENIAC) was the first binary programmable computer using this architecture.

Prediction that the number of transistors on a chip doubles roughly every two years while cost halves.

Input Devices: Convert data into a digital format (keyboard, mouse, scanner, camera).
Output Devices: Display results for humans to understand (monitor, projector, printer, speakers).
Central Processing Unit (CPU): The "brain" of the computer that performs operations.
Memory: Stores data and instructions for the CPU. (RAM: primary: temporary; ROM: secondary: permanent).
Primary memory: (RAM, Cache, ROM) Data stored temporarily for immediate processing.
Secondary memory: (Hard Disk, SSD, optical drives) Used for permanent data storage.
System Interconnections (Bus): Transfer data between components. Includes address, data, and control buses that coordinate data movement between CPU and other components.

Memory is essential for storing data and instructions.
Units of Memory: Bit, Nibble, Byte, Kilobyte, Megabyte, Gigabytes, Terabytes, Petabytes, etc.
Types of Memory: Primary vs. Secondary.

System software: Manages computer hardware resources, like the Operating System. Includes utilities, device drivers, and BIOS.
Application software: Performs specific tasks for users (e.g., word processing, web browsing).
Language Translators: Convert high-level programming languages to machine-executable code.