Overview of Computer Systems and Basics

Scheme of Work

• Week 1: Overview of computer systems (hardware, software, people)
• Week 1: Historical development of computing devices (pre-computing devices)
• Week 1: 20th/21st-century computers (ENIAC, EDSAC, microcomputers)
• Week 2: Input devices
• Week 3: Output devices
• Week 4: Operating systems
• Week 5: Midterm break
• Week 6: The future of computing (robotics and artificial intelligence)
• Week 7: Programming languages
• Week 8: Introduction to BASIC programming

Computer System Overview

• A computer performs four basic functions: accepts data, stores data, processes data, and gives out information.
• A computer system is an electronic machine that accepts, stores, and processes data into meaningful information.
• Computer hardware are the physical parts of a computer.
• The computer is made up of hardware and software.
• Input devices: keyboard, mouse, scanner
• Output devices: monitor, printer, plotter
• Central Processing Unit (CPU): Control unit, Arithmetic Logical Unit (ALU)
• Storage devices: Primary storage (RAM), secondary storage (hard disk, flash drives)
• Multimedia devices

Computer Hardware (Input Devices)

• Input devices allow users to enter data, commands, and programs into a system.
• Examples include keyboards, mice, scanners, joysticks, and graphics tablets.

Computer Hardware (Output Devices)

• Output devices display information to the user.
• Examples include printers, plotters, monitors, speakers, and headphones.

Computer Hardware (Storage Devices)

• Storage devices hold information/programs temporarily or permanently.
• Examples include primary storage (RAM) and secondary storage (hard disks, flash drives, compact discs, magnetic tapes).

Computer Hardware (System Unit)

• Includes the motherboard, CPU, memory (RAM), and power supply unit (PSU)
• Motherboard: distributes power, enables communication to and from RAM, CPU, and other hardware.
• CPU: interprets and executes computer commands; has a control unit and ALU
• RAM: stores data and programs for immediate processing
• PSU: provides power for the computer

Computer Hardware (Peripherals)

• External devices connected to the CPU
• Input examples: keyboard, mouse, joystick, graphics tablet, touchpad, microphone, scanner, web camera
• Output examples: printer, monitor, plotter, speakers, headphones, media projector

Computer Hardware (Storage Devices)

• Auxiliary memory external to the system unit
• Examples: hard disk, flash drives, floppy disks, CDs, DVDs, memory cards

Computer Software (Operating System)

• System software manages computer resources, including applications and user interface tools.
• Operating system Examples: MS-Windows, macOS, Linux

Computer Software (Translators)

• Software that translates program written in one level of programming to another level; examples include Compiler, Interpreter, Assembler

Computer Software (Utility Programs)

• Programs for managing system resources (e.g., disk drives, memory), like routines for debugging, copying files, editing routines and antivirus

Computer Software (Application Software)

• Programs for performing specific tasks (e.g., word processing, web browsing, graphics, games.)
• Examples: web browsers, word processors, spreadsheets, databases, presentation software, graphics software, media players and games

The History of Computing (Pre-Computing Era to 19th Century)

• Early computing devices: abacus, slide rule, Napier's bones, Pascal calculator, Leibniz multiplier, Jacquard loom, Analytical Engine, Hollerith census machines, Burroughs's machine

The History of Computing (20th Century to Date)

• 20th-century computers: ENIAC, EDVAC, UNIVAC, Manchester Mark 1, Harvard Mark 1 etc.
• Features of the ENIAC: vacuum tubes, circuitry memory component, large & enormous panels, consumed high energy, used binary coding instructions
• UNIVAC I: the first commercially available computer

Microcomputers

• Small, affordable, and common type of computers
• Based on microprocessor chip technology
• Examples: desktops, laptops, palmtops, and personal digital assistants

Programming Languages

• Programming is the act of giving instructions to a computer
• Programming languages are used for communication between programmers and computers to create programs
• Three levels: machine language, low level language (assembly language), high-level language
• Advantages of high-level languages: easier to learn and use, user friendly, faster to write programs, easier to maintain, machine-independent
• Disadvantages of high-level languages: consumes more memory, difficult to translate, and time-consuming
• Examples of high-level programming languages: FORTRAN, COBOL, PASCAL,BASIC, C++, Java, APL, Python

Programming with BASIC

• BASIC (Beginner's All-purpose Symbolic Instruction Code): a high-level programming language
• It's easy to learn and use because of the rules
• It has a command language for operating systems

BASIC Statements

• REM: inserts comments or remarks in a program.
• LET: assigns a value to a variable.
• INPUT: collects input from the user.
• READ, DATA: enters data into a program before running.
• FOR, NEXT: facilitates repetition or iteration.
• SAVE: saves a copy of a program to a storage device.
• PRINT: displays output.
• END: terminates the running of the program.

Simple BASIC Programs (Examples)

• Programs that perform basic operations, like addition, subtraction, division, multiplication, and outputting specific data, using BASIC instructions.