Study sheet: Computer System Fundamentals

📋 Course Outline

1. Computer Definitions and Categories
2. Computers for Individual Users
3. Computers for Organizations
4. Computers in Society
5. Computers Across Economic Sectors
6. Computer System Components
7. Information Processing and Hardware
8. Memory, Input, Output, and Storage
9. Software, Data, and Users
10. Users and Computer Independence
11. Computer Roles and Careers
12. Keyboard Structure and Input
13. Mouse Techniques and Variants
14. Stationary Pointing Devices
15. Ergonomics and Repetitive Injuries
16. Handheld and Optical Input
17. Audio and Speech Input
18. Speech Recognition and Audio Input

📖 1. Computer Definitions and Categories

🔑 Key Concepts & Definitions

• Computer : an electronic device that processes data, converting it into information that is useful to people, and programmed instructions control its purpose and operation.

★ Must-know

📌 Digital computers represent information as separate numerical values and process each unit in a strict sequence, whereas analog computers represent data as variable points along a continuous spectrum.

Further detail

• Computers can be categorized by:
  • intended users
  • operating power
  • price
  • hardware
  • software they can run

💡 Memory Hook

Digital computers use distinct values, whereas analog computers use a continuous spectrum.

📖 2. Computers for Individual Users

🔑 Key Concepts & Definitions

• Personal computer : a computer system designed for use by a single person; personal computers are also called microcomputers.
• Workstation : a specialized single-user computer with more power and features than a standard desktop PC, commonly used for advanced design, modeling, animation, and video editing.

★ Must-know

• The six primary types are:
  • desktop computers
  • workstations
  • notebook computers
  • tablet computers
  • handheld computers
  • smart phones

Further detail

📌 Notebook computers are portable, fully functional microcomputers that can run on alternating current or batteries, whereas desktop computers are full-size systems designed to remain on or near a desk.

• Tablet PCs provide notebook functionality while accepting input from a stylus or digital pen, and many also support voice input, networking, keyboards, and full-size monitors.

💡 Memory Hook

Desktop → workstation → notebook → tablet → handheld → smartphone

📖 3. Computers for Organizations

🔑 Key Concepts & Definitions

• Network server : usually a powerful personal computer with specialized software and equipment that functions as the primary computer in a network.
• Mainframe computer : a large, powerful system used by organizations such as banks and insurance companies to let many users access the same data and specialized tasks.
• Minicomputer : also called a midrange computer, has capabilities between those of mainframes and personal computers and can serve the input and output needs of hundreds of users.

📝 Essential Points

📌 A dumb terminal only provides input and output for a remote computer, whereas an intelligent terminal can perform some processing but usually has no storage.

• Supercomputers are the most powerful computers made, and the fastest can perform more than one trillion calculations per second.

💡 Memory Hook

Servers emphasize flexible shared services, whereas mainframes emphasize powerful specialized tasks.

📖 4. Computers in Society

🔑 Key Concepts & Definitions

• Information : Information includes facts, mathematical formulas and results, building plans, recipes, pictures, songs, addresses, games, menus, shopping lists, and resumes that computers can store and process as data.

★ Must-know

• Computers are important because they help people work with information and create new information.

Further detail

• Home computers are commonly used for communication, business work, schoolwork, entertainment, and personal finances.

💡 Memory Hook

Better information processing → changes in work, communication, education, and daily life.

📖 5. Computers Across Economic Sectors

★ Must-know

• Industry uses computers for computer-aided design and manufacturing, shipping management, and process control.

• Health-care applications include:

  • ultrasound
  • magnetic resonance imaging
  • laser eye surgery
  • fetal monitoring
  • robotic surgery
  • surgeon training
  • patient records
  • scheduling
  • billing
  • transactions with insurers and pharmacies

Further detail

• Small businesses use computers for:

  • accounting
  • inventory management
  • marketing
  • payroll

• Government applications include:

  • population
  • taxes
  • military
  • police

📖 6. Computer System Components

🔑 Key Concepts & Definitions

• Computer system : a combination of hardware, software, data, and a user
• Hardware : any tangible part of a computer, including interconnected electronic devices used for control, input, and output
• Software : a set of instructions that tells a computer what to do and enables it to perform tasks

★ Must-know

📌 Data consists of individual facts or pieces of information that may lack meaning by themselves, whereas information is data placed in a useful context.

Further detail

• People remain essential to computer systems because they design, build, program, repair, start, and direct computers, even when the systems operate without constant supervision.

💡 Memory Hook

HSDU: Hardware, Software, Data, User

📖 7. Information Processing and Hardware

🔑 Key Concepts & Definitions

• Processor : The processor, also called the central processing unit (CPU), organizes and carries out instructions from the user or software.
• Input : Input is the stage in which a computer accepts data from a user, a program, or another computer system for processing.

★ Must-know

• The information processing cycle consists of:
  • input
  • processing
  • output
  • storage

📌 Output displays or transfers processing results and is optional, whereas storage permanently saves processing results and is also optional.

• Computer hardware devices fall into four categories:
  • processor
  • memory
  • input and output
  • storage

Further detail

• The motherboard is the main circuit board that connects the processor and other hardware components.

💡 Memory Hook

Input → Processing → Output → Storage

📖 8. Memory, Input, Output, and Storage

★ Must-know

• RAM temporarily holds data and program instructions while the CPU uses them, whereas ROM permanently stores instructions needed to start and operate the computer.

• RAM loses its contents when the computer is shut off or power fails, so users should save data files to storage devices frequently.

• Input devices accept data and instructions, whereas output devices present processed data to users or other computer systems.

• Storage retains data when the computer is turned off and offers more capacity at lower cost, whereas memory is faster but temporary and more expensive.

• Magnetic storage uses read/write heads on magnetic disks, whereas optical storage uses lasers to read or write reflective discs.

Further detail

• The common units for measuring computer memory and storage are:

  • byte
  • kilobyte (KB)
  • megabyte (MB)
  • gigabyte (GB)
  • terabyte (TB)

• The most common input devices are the keyboard and mouse, while the most common output devices are the monitor and printer.

• A standard DVD can store at least 4.7 GB and as much as 17 GB of data.

💡 Memory Hook

RAM is a temporary worktable, whereas storage is a permanent file cabinet

📖 9. Software, Data, and Users

🔑 Key Concepts & Definitions

• Operating system : An operating system interprets requests between hardware, application programs, and the user and tells the computer how to use its components.
• File : A file is a named set of data, and a document is a file that a user can open and use.

★ Must-know

📌 System software controls hardware and maintains the computer, whereas application software helps users perform specific tasks.

• The three basic types of system software are:
  • operating systems
  • network operating systems
  • utilities

📌 Data is intended for people to use, whereas programs are instructions intended for computers to use.

Further detail

• Application software includes:
  • word processors
  • spreadsheets
  • database management software
  • presentation programs
  • graphics programs
  • multimedia authoring applications
  • Internet applications
  • games

💡 Memory Hook

System software controls the computer, whereas application software serves the user

📖 10. Users and Computer Independence

🔑 Key Concepts & Definitions

• User : an essential part of a complete personal computer system because the user provides interaction, instructions, and management that the computer cannot perform by itself.
• Operating system : typically installed on special memory chips and programmed to monitor a function or check for a failure.

📝 Essential Points

📌 Personal computers are designed for human interaction, whereas userless computers are programmed to perform a specific set of tasks independently after they have been installed and started.

💡 Memory Hook

Personal computers need users; embedded computers can operate independently.

📖 11. Computer Roles and Careers

★ Must-know

• When working with a personal computer, the user may set up or configure the system, install software, run programs, manage files, and maintain the system.

Further detail

• Restaurant, grocery-store, and retail managers use computer systems to monitor inventories, track transactions, and manage product pricing.

• Courier dispatchers use computerized terminals to schedule deliveries, locate pickup and drop-off points, generate invoices, and track packages.

• Construction managers and estimators use specialized software to analyze construction documents and calculate the materials and time required for a job.

• Automotive mechanics and technicians use computer systems to measure vehicle performance, diagnose mechanical problems, and determine maintenance or repair strategies.

💡 Memory Hook

Set up → install → run → manage → maintain.

📖 12. Keyboard Structure and Input

🔑 Key Concepts & Definitions

• Modifier keys : keys such as SHIFT, ALT, and CTRL change the input or action produced by another key.

★ Must-know

• The five keyboard groups are:

  • alphanumeric keys
  • modifier keys
  • numeric keypad
  • function keys
  • cursor-movement keys

• Keyboard input passes from a pressed key to the keyboard controller, into the keyboard buffer as a code, then to system software and finally to the CPU.

Further detail

• The numeric keypad's NUM LOCK key makes its numeric keys enter numbers; when NUM LOCK is deactivated, those keys perform cursor-movement and other functions.

💡 Memory Hook

A-M-N-F-C: Alphanumeric, Modifier, Numeric, Function, Cursor-movement.

📖 13. Mouse Techniques and Variants

🔑 Key Concepts & Definitions

• Mouse : an input device moved across a flat surface to control the on-screen pointer, which selects text, menus, programs, files, and data.
• Trackball : a stationary pointing device with an exposed ball that the user rolls with a finger or thumb to move the pointer, requiring less space than a mouse.
• Trackpad : a stationary pointing device that translates finger movement across a touch-sensitive surface into pointer movement.

★ Must-know

• Mouse use combines:
  • pointing
  • clicking
  • double-clicking
  • dragging
  • right-clicking

Further detail

📌 A mechanical mouse detects movement with a rubber ball, rollers, and sensors, whereas an optical mouse uses reflected light to determine movement.

💡 Memory Hook

Point → click → double-click → drag → right-click.

📖 14. Stationary Pointing Devices

🔑 Key Concepts & Definitions

• Trackball : a stationary pointing device that works like an upside-down mouse, using a ball moved by the index finger or thumb to control the screen pointer
• Integrated pointing device : An integrated pointing device is a small joystick built into a portable computer keyboard, typically between the G and H keys, that controls the screen pointer without requiring the user's hands to leave the keyboard.

📝 Essential Points

• Trackpads may include two or three buttons that perform mouse-button functions, and some are strike-sensitive so users can tap the pad instead of pressing its buttons.

💡 Memory Hook

Trackball and trackpad stay still, whereas a mouse moves across the desk.

📖 15. Ergonomics and Repetitive Injuries

🔑 Key Concepts & Definitions

• Ergonomics : the study of the physical relationship between people and their tools, including computers, to reduce strain and injuries through suitable designs and techniques
• Repetitive stress injury : results from continuously using the body in ways it was not designed to work
• Carpal tunnel syndrome : a wrist or hand injury in which inflamed tendons in the wrist's carpal tunnel press against nerves, causing tingling, numbness, pain, or inability to use the hands

📝 Essential Points

📌 To reduce keyboard-related injuries, users should keep their wrists straight, sit upright with their feet flat, take frequent breaks, and use an ergonomically designed keyboard when appropriate.

💡 Memory Hook

Stiff wrists → inflamed tendons → nerve pressure → pain and numbness.

📖 16. Handheld and Optical Input

🔑 Key Concepts & Definitions

• Pen-based system : A pen-based system uses a pen or stylus to write, draw, point, tap, or enter data on a special pad or directly on a screen.
• Touch screen : accepts input when the user places a fingertip directly on the screen, usually to select an option from a menu
• Optical character recognition : software translates a scanned bitmap of printed characters into editable text that the computer can interpret as letters and numbers

★ Must-know

• A bar code reader emits light onto a printed bar code, detects the reflected pattern, converts the bars into numeric digits, and sends the data to the computer as if it had been typed.

Further detail

• Common uses of pen-based systems include: note-taking, short messages, annotations, data collection, signatures or messages stored and transmitted as graphic images

📌 Game controllers generally fall into two broad categories: game pads, which are small flat devices with controls for both hands, and joysticks, which direct a vehicle or character and are popular in racing and flying games.

📌 Handheld scanners are more portable but typically require multiple passes for one page, whereas flatbed scanners provide higher-quality reproduction and can scan a page in one pass.

💡 Memory Hook

Pen, touch, game controller; then bar code reader and scanner.

📖 17. Audio and Speech Input

🔑 Key Concepts & Definitions

• Speech recognition : also called voice recognition, translates spoken words into text and can allow users to control a computer with commands such as Open or Cancel

★ Must-know

• A microphone captures analog sound, a sound card digitizes the sound into codes the computer can store and process, and the computer can convert digital sound back into analog signals for speakers.

Further detail

• Speech-recognition systems usually require training in which the user reads passages into a microphone so the computer learns how that speaker pronounces sounds.

• Even the best-trained speech-recognition systems may make as many as one recognition mistake for every 100 sounds they hear, despite providing better than 99 percent accuracy.

💡 Memory Hook

Microphone captures sound → sound card digitizes it → software records or recognizes it.

📖 18. Speech Recognition and Audio Input

🔑 Key Concepts & Definitions

• Digitizing : The process of converting analog audio signals into digital codes that a computer can store and process
• Speech recognition : Also called voice recognition, translates spoken words into text or commands that a computer can understand
• Webcam : A popular and inexpensive type of PC video camera that can sit on top of a monitor or on a stand
• Video capture card : Connects video devices such as VCRs and camcorders to a PC, allowing images to be transferred between the devices and the computer
• Digital camera : A portable handheld device that captures still images electronically, digitizes and compresses them, and stores them on a special memory card

★ Must-know

• Speech-recognition software analyzes phonemes, the smallest individual sounds in a language, and must use context to distinguish words with the same sound, such as “two” and “too,” while filtering background noise.

• Some speech-recognition packages accurately recognize 80 to 90 percent of spoken words using large stored vocabularies, while newer systems can provide better than 99 percent accuracy but may still make one recognition mistake for every 100 sounds.

• A sound card converts analog signals from sources such as microphones, phonograph records, and cassette tapes into digital code, while it can convert digital sounds back into analog signals for speakers.

• 🔄 A computer video camera processes moving images by: breaking the image into individual pixels, storing each pixel’s color and other characteristics as digital code, compressing the code for storage or network transmission

• A hardware maintenance technician installs and configures hardware, installs peripherals, upgrades computers, handles network-related hardware issues, and troubleshoots and repairs hardware.

Further detail

📌 Speech-recognition software may require users to train it to recognize their speech patterns or pronunciations, and most commercial packages use a noise-canceling microphone to filter background noise.

• MIDI, or Musical Instrument Digital Interface, allows electronic musical instruments to communicate with and control one another and enables a computer to record their output.

• Images from a digital camera can be copied to a PC for editing, copying, printing, embedding in documents, or transmitting to another user.

• Hardware technicians may advise companies about system development, expansion, and acquisitions because they work directly with end users and understand their needs.

• 🔄 The voice-recording exercise follows these steps:

  1. open Sound Recorder
  2. click Record and speak into the microphone
  3. click Stop
  4. click Play
  5. close the program without saving if prompted

💡 Memory Hook

Analog sound → digitizing → computer storage and processing

📊 Synthesis Tables

Computer Types by Users and Purpose

Type	Typical users	Main characteristic
Personal computer	One user	Individual computing
Network server	Many network users	Shared services and resources
Mainframe	Many organizational users	Powerful specialized tasks
Minicomputer	Up to hundreds of users	Intermediate capability
Supercomputer	Research and large-scale organizations	Extreme calculation power

Memory and Storage Comparison

Dimension	Memory	Storage
Purpose	Holds data and instructions currently in use	Keeps programs and data permanently
Power state	RAM loses contents when power stops	Contents remain after shutdown
Speed and cost	Faster and more expensive	Slower and cheaper