Knowt
Unit 2
Content notes
Parts of the computer
Data processing devices
Input, process, and output information
Store it for later use
Thinks in terms of 0 and 1s
A 0 and a 1 is a bit
Eight 0 and 1s is a byte
Binary
Roomba is sophisticated and learns
Has a embedded computer
Inputting data
Keyboard
Laser keyboard
A virtual keyboard on your desk
Images
Camera or webcam
Sound
Mics
Headsets
Output
Monitors
CRT used to popular
LCD monitors now
Printers
Inkjet
Impact printer in the past
Laser printer; expensive for new cartridges
Printers as all in ones
Motherboard
Peripheral items attach either directly or a cable
CPU or memory
Hard drive
Stores data
Internal or external
Internal is direct external is usb
Ergonomics
Pains being caused
The way we sit
Computer is a data processing device that performs 4 major functions
Gathers data (input)
Processes data into information
Outputs data or information
Stores data and information
Data is a representation of a fact or idea
Data can be a number, word, picture, or recording
Information is data that has been organized or presented in a meaningful fashion
Data that is useful
Computers use binary language; zero and one
Each zero and one is a bit
Eight binary digits combine to create a byte
In computers, each letter of the alphabet, each number, and each special character (such as the @ sign) consists of a unique combination of 8 bits, or a string of eight 0s and 1s
As it turns out, if 8 bits are put together there are 256 possible combinations that they can be in. That number of combinations allows for a code that can include all the uppercase and lowercase letters of the alphabet, all 10 digits, punctuation marks, and many other much-used symbols. We call these 8 bits working together a byte. Bytes are the basic measurement for storage in a computer.
Byte (B) 1 byte
Kilobyte (KB) 1024 bytes
Megabyte (MB) 1,048,576 bytes
Gigabyte (GB) 1,073,741,627,776 bytes
Terabyte (TB) 1,099,511,627,776 bytes
Petabyte (PB) 112,589,990,684,262 bytes
Software is the set of computer programs that enables the hardware to perform different tasks
Application software: the set of programs you use on a computer to help you carry out tasks. If you’ve ever typed a document, created a spreadsheet, or edited a digital photo, for example, you’ve used a form of application software.
System software: he set of programs that enables your computer’s hardware devices and application software to work together. The most common type of system software is the operating system (OS). It manages the hardware of the computer system such as the monitor and the printer. The operating system also provides a means by which users can interact with the computer.
Hardware components: system unit and peripheral devices
Devices such as monitors and printers that connect to a computer
Hardware devices like routers help a computer communicate with other computers to facilitate sharing documents and other resources
System unit and peripheral devices perform four main functions:
Input
Process
Output
Store
Hardware terms:
Motherboard: a circuit board that holds the CPU, RAM, Expansion cards, and other built in components
RAM vs. ROM: RAM is non-permanent memory. It is used to store current instructions and data while ROM stores your start-up instructions and is permanent memory.
CPU: The Central Processing Unit controls all functions of the computer. It is often called the brains. Like our brains, it can perform a large number of tasks per second.
Hard drive: The main storage for your data. This is normally permanently mounted within your computer.
Drive bays: Hold components of the computer such as hard drives, CD and DVD Roms drives.
Ports: These are used to connect external hardware to your computer. USB ports are an example.
QWERTY keyboards
Designed for typewriters, not computers
Meant to slow typists to prevent typewriter keys from jamming
Considered inefficient
Enhanced features include number, function, and navigation keys
Speciality keyboards
Notebook computers
Notebook computers are portable computers that are powered by batteries and have keyboards, monitors, and other devices integrated into a single compact case.
notebook keyboards are more compact than standard keyboards and therefore have fewer keys
lot of the notebook keys have alternate functions so that you can get the same capabilities from the limited keys as you do from the special keys on standard keyboard
Many notebook computers using Windows 8 feature touch sensitive screens
A personal digital assistant (PDA)
an electronic device, which can include some of the functions of a computer, a cell phone, a music player, and a camera
you enter data and commands by tapping or writing on the PDA’s touch-sensitive screen
Tablet PCs
similar to notebook PCs but also feature a touch-sensitive screen and handwriting recognition software
Tablet PCs usually also allow user input via a stylus
Wireless keyboards
powered by batteries and send data to the computer using a form of wireless technology
Virtual Laser Keyboards and Configurable keyboards
Mice/ mouse
Optical mouse
Uses internal sensor or laser to detect movement
no moving parts on the bottom so there is no way for dirt to interfere with the mechanisms and less chance of parts breaking down
Trackball mouse
remains stationary and doesn’t demand much wrist motion, so it’s considered healthier on the wrists
Less popular now
Touch pad mouse
Laptops have them
This is a small glass area that is sensitive to the touch and as you move your finger along the surface, the mouse follows.
Wireless mouse
send data to the computer by radio or light waves
Other input devices
Scanners
copy images from existing sources, digitize them, and make them available for editing or processing in the computer as well as viewing on the screen
Digital cameras
Make a digital file of an image for editing, printing, or distribution on the Web.
Digital movies can be created with a digital video camera and edited and distributed electronically
Webcams
small cameras that usually sit on top of your computer monitor or are built into your notebook computer
Although some webcams are able to capture still images, they are used mostly for transferring live video directly to your computer
Microphones
capture sound waves and transfer them to your computer to be stored in a digital format
Microphones come with most computers, but if you didn’t get a microphone with your computer, you may want to buy a desktop microphone if you plan to record your own audio files.
A headset microphone is best for videoconferencing and speech-recognition uses
Videoconferencing technology allows a person sitting at a computer equipped with a personal video camera and a microphone to transmit video and audio across the Internet (or other communications medium).
With speech-recognition systems, you can operate your computer through a microphone, telling it to perform specific commands or to translate your spoken words into data input.
Visually impaired devices like voice recognition or large keyboards (touch screen or physical) to input data
Special trackballs designed for one finger use for those with severe motor control problems
Can be mounted anywhere
Head-mounted pointing devices can be used for those the restrained arm motion
Output devices
Send processed data out of your computer
The output can take the form of text, pictures (graphics), sounds (audio), and video.
One common output device is a monitor, which displays text, graphics, and video as soft copies (copies you can see only on-screen).
Another common output device is the printer, which creates tangible or hard copies of text and graphics.
Speakers are the output devices for sound.
Monitor types
Liquid crystal display (LCD), light-emitting technology (LED), cathode-ray tube (CRT)
LCD and LED: flat, found in laptops
CRT: appearance of a traditional TV set, outdated
Legacy technology: uses techniques, parts and methods that are no longer popular
Printers
Inkjet and laser
Inkjet printers spray ink or while laser printers use laser beams to transfer marks on the paper.
There are also a number of specialty printers on the market, including multifunction printers, plotters, and thermal printers
Chapter 2 Notes
Google has introduced Willow
Quantum computing chip
Solved a problem in 5 minutes that takes the worlds fastest supercomputers 10 septillion years
Uses particle physics
Offers advantages for complex calculations
Practical applications remain experimental
The chip demonstrates progress in error correction, addressing a key challenge in quantum computing.
Willow reduces error rates as qubits are added, unlike earlier models where errors increased with scale.
Breakthrough points to potential for larger, more reliable quantum systems in the future.
Applications include nuclear fusion reactor design, car battery improvements, and pharmaceutical research.
Commercial quantum computers solving diverse real-world problems are still years away.
Critics note Willow solved a problem designed for quantum computers, not proving universal superiority over classical computers.
Multiverse theory entered discussions, with claims Willow's computations align with parallel universes, though this remains speculative.
Countries and private firms are heavily investing in quantum technology.
Despite Willow's milestone, researchers stress the need for further development to make quantum computing widely practical.
Computer technology has improved many aspects of life.
E-waste (broken or unwanted computer products) is a significant issue.
Computing equipment contains hazardous toxins, qualifying it as hazardous waste.
Disposing of e-waste in regular trash is not environmentally friendly.
Broken equipment should be handled by qualified disposal professionals.
Functional equipment can be donated to extend its use and reduce waste.
Computers work exclusively with numbers
Binary language (0 and 1)
Each is a binary digit: bit
8 bits is a byte
Computers only understand on and off
Computers use two states, on (1) and off (0), represented by electrical switches.
These switches combine in various ways to perform operations and move data within the system.
Early computers used transistors made from semiconductors like silicon as electrical switches.
Silicon's conductivity can be controlled by adding specific chemicals, enabling it to act as an on/off switch.
Transistors allow or block electric current flow based on applied voltage.
To increase capacity, integrated circuits were developed to pack more transistors into smaller spaces.
Integrated circuits (chips) are small semiconductor regions that hold billions of transistors.
Chips, often no larger than a quarter inch, enable compact and powerful microprocessors.
Microprocessors contain the CPU, the "brains" of the computer, where data processing occurs.
Modern CPU chips can contain over 100 billion transistors.
Bits and bytes represent both the language of computers and the quantity of data processed.
Files, images, and software are stored as series of bits and bytes, often reaching billions of bytes in size.
Larger units like kilobytes (1,000 bytes), megabytes (1 million bytes), and gigabytes (1 billion bytes) simplify measuring file sizes.
Modern personal computers store terabytes (1 trillion bytes), while business systems can store up to petabytes (1,000 terabytes).
Google processes over one petabyte of user data per hour.
Computers use hardware and software to process data into information for tasks like writing or gaming.
Hardware refers to the physical components of a computer.
Software is a set of programs that enable hardware to perform tasks.
The operating system (OS) controls computer functions and is a common type of software.
Popular operating systems include Microsoft Windows and Apple macOS.
Two designs of computers: portable and stationary
Portable: cell phones, tablets, and laptops
Cell phones:
Cell phones have components similar to computers: CPU, memory, and input/output devices.
Cell phones require software, effectively making them computers.
Smartphones have powerful CPUs and interfaces for tasks like videoconferencing, HD video editing, and live streaming.
Smartphones are defined by their ability to use Internet features easily, often requiring a data plan.
Devices like the iPhone and iPad showcase digital convergence by combining features once exclusive to separate devices, including:
Internet access
Voice recording
Music playback and organization
GPS services
Digital image and video capture
Computing for programs like word processors and video editing
Control of smart home devices
Smartphones' screen size limits their usability for extended work periods.
Foldable phones, like Samsung Galaxy Fold and Huawei Mate X, address this with 7- to 8-inch screens.
When folded, these devices remain pocket-sized.
Foldable phones may advance the vision of a single device for all computing needs
Tablets
Tablets, like the Apple iPad and Amazon Fire, are portable computers with multi-touch screens.
They feature on-screen keyboards but can connect to external keyboards.
Tablets are lightweight and portable, though heavier than smartphones.
Popular tablets include Apple iPad and Samsung Galaxy, with over 100 models available.
Android runs on both tablets and phones, while Apple uses iOS for iPhones and iPadOS for tablets.
Tablets and smartphones are Bluetooth-enabled, allowing wireless data transfer to other Bluetooth devices.
Bluetooth uses radio waves for data transmission over distances up to 1,000 meters.
Laptops
Laptops are portable computers with integrated keyboards, monitors, and other devices.
Variants of laptops include 2-in-1 PCs, ultrabooks, and Chromebooks.
A 2-in-1 PC can function as both a laptop and a tablet, with a detachable or foldable keyboard.
2-in-1 PCs offer more powerful CPUs and use full traditional OS (e.g., Windows), unlike tablets with mobile OS.
Ultrabooks are thin, lightweight laptops with long battery life, using SSD drives and USB-C connectors.
Ultrabooks are under 3 pounds, have 13- to 15-inch screens, and full-size keyboards.
Chromebooks use Google Chrome OS, storing documents and apps in the cloud, and are designed for constant internet connectivity.
Chromebooks are lightweight and inexpensive, but cannot run software requiring installation on a hard drive.
Choosing a Portable Device
Power: How much computational power do you need?
Screen size and resolution: These cannot be changed later, so make sure the quality and size of screen will fit your needs for the years you’ll keep the device.
Style of keyboard: Do you want a touch-based interface? Is a physical keyboard important, or is an on-screen keyboard sufficient? Does the feel of the keyboard work for you?
Battery life: Some devices can operate for 15 hours continuously, others fewer than five. Investigate whether the battery can be upgraded and how much weight that would add.
Weight: Does an additional two pounds matter? (Lighter devices usually cost more.) Remember to include the weight of any charging device you would need to carry when you travel as you consider the trade-off in price for a lighter device.
Number of devices: Is this your only computing device? As technology prices fall, you may be able to have more than one device. You might find an affordable solution that includes both a very mobile device and a second, more powerful one.
Stationary computers
Desktop computers are stationary, with a case or tower (system unit) housing the main components and peripherals like monitors and keyboards attached.
All-in-one computers, like the Apple iMac, integrate the processor and memory into the monitor, eliminating the need for a separate system unit.
Some all-in-one models feature touch-screen technology.
Advantages of desktop computers include easier upgrades, especially for gamers and graphic artists needing better components.
Large screens are more convenient for desktops, ideal for tasks like graphic design.
Desktop computers often provide better value for computing power, as miniaturization in portable devices is costly.
Mainframes are large, expensive computers that support many users at once, often used in businesses managing large data, like insurance companies for tasks like claims processing.
Supercomputers are designed for rapid, complex calculations and are used for tasks like weather forecasting, executing a few programs very quickly.
Embedded computers are small, self-contained chips found in devices like cars, drones, or home thermostats, with their own programming and minimal user interaction.
Devices like Wi-Fi adapters and routers enable computers to communicate with the Internet and share resources.
The exploration of hardware begins with input devices.
Supercomputers are the largest and most powerful computers, used for complex problems and massive computations.
Some supercomputers are single units with multiple processors, while others are networks of multiple computers working together.
The IBM Summit, the fastest supercomputer in the US (number 2 worldwide), has 4,356 nodes, each with two 22-core CPUs, and runs at 148.8 petaflops.
Fugaku, located in Japan, is currently the fastest supercomputer in the world.
The longevity of these top spots is uncertain as technology rapidly evolves.
Input device: enables users to enter data (text, images, and sounds) and instructions (user responses and commands) into a computer
Physical keyboards and touch screens
A keyboard is a primary input device used to enter data and commands.
Touch screens on devices like smartphones and tablets use virtual keyboards, which support multiple languages and character sets.
The standard QWERTY layout is the most common for both virtual and physical keyboards, with options to customize layouts for different languages.
Most keyboards have alphabetic, numeric, and special keys for shortcuts and functions (e.g., Alt, Ctrl, and Function keys).
Regular (membrane) keyboards use rubber membranes for input; mechanical keyboards have spring-loaded switches, are more durable, and offer better typing comfort but are noisier and more expensive.
Physical keyboards can be added to devices via wired connections or wireless technologies like Bluetooth.
Bluetooth keyboards often integrate with tablet cases for portability and protection.
Alternatives to physical keyboards include:
Flexible keyboards, which are portable and plug into USB ports.
Laser-projection keyboards that project a virtual keyboard on a flat surface and detect typing motions via sensors.
These keyboard options cater to varying user preferences and device compatibility.
Mice and other pointing devices
A mouse is the most common pointing device for entering responses and commands.
Optical mice use an internal sensor or laser to detect movement and communicate pointer location to the computer.
Mouse pads are optional but can improve movement on uneven surfaces or protect work surfaces.
Traditional mice have 2–3 buttons for executing commands and opening shortcut menus.
Customizable mice offer programmable buttons and wheels for quicker navigation and are adjustable for hand size and grip style.
Beneficial for gamers, users with physical limitations, or those prone to repetitive strain injuries.
Wireless mice connect via Bluetooth or a USB receiver.
Touch-screen devices can benefit from a mouse for precision tasks, especially when using a physical keyboard.
Touch mice, like Apple's Magic Mouse, have no defined buttons and use taps or swipes to perform actions like scrolling and zooming.
Laptops use integrated pointing devices, such as touchpads or trackpads, located below the keyboard.
Touchpads are multi-touch sensitive, allowing various gestures (e.g., two-finger scrolling, taps for clicks).
Settings for touchpads can be customized in operating systems like Windows and macOS.
Game controllers (e.g., joysticks, game pads, steering wheels) are input devices.
They send data to computing devices.
Controllers used for gaming consoles (e.g., Xbox Series X) can also be used with computers.
Digital cameras, camcorders, and mobile-device cameras capture pictures and video as input devices.
Flatbed scanners (in multi-function printers) input images, creating digital files instead of paper copies.
Mobile phone cameras can scan information, such as UPC codes for apps like MyFitnessPal.
Retail scanners input UPC data into point-of-sale systems.
Scanning apps digitize paper documents into formats like PDF.
Webcams (built-in or external) capture and transmit live video, widely used in videoconferencing.
Videoconferencing apps (e.g., Zoom, Microsoft Teams) gained popularity for work and education during the pandemic.
Microphones input sound waves into digital formats, enabling audio conferences, recording, and voice control.
Voice recognition allows device control via speech, supported in Windows, Chrome OS, and macOS.
Intelligent personal assistants (e.g., Siri, Google Assistant, Alexa, Cortana) perform tasks based on voice commands, using Internet access and location services.
Other microphones
Close talk
Attached to a headset (allows fro listening)
Leaves hands free
Best sed for video conferencing, phone class, speech recognition
Omnidirectional
Picks up sounds equally well from all direction
Best used for conference calls in meeting rooms
Unidirectional
Picks up sound from only one direction
Best used for recording with one voice (ie podcasts), and video conferencing when high quality is required
Clip on (lavalier)
Clips to clothing
Available as wireless
Best used for presentations requiring freedom of movement and leaves hands free for writing on whiteboards
Smartphones and tablets include various sensors that detect or measure data for hardware or apps.
Magnetometer: Detects magnetic fields; used in compass and metal-detecting apps.
Proximity sensor: Detects when the phone is near the ear, turning off the display during calls.
Light sensor: Adjusts screen brightness based on ambient light.
Accelerometer: Measures acceleration and determines device orientation (landscape/portrait).
Gyroscope: Provides precise orientation information.
Barometer: Measures atmospheric pressure to improve GPS accuracy and track elevation changes.
Thermometer: Monitors internal or ambient temperature to prevent overheating.
Pedometer: Tracks the number of steps taken.
Fingerprint sensor: Secures the device by recording and reading fingerprints.
Heart rate monitor: Measures pulse rate via blood vessel detection.
LiDAR: Maps object shapes and measures distances.
Foldable phones
Foldable phones are emerging as potential ultimate digital convergence devices.
Major drawback: current foldable phones use plastic screens, which compromise image quality.
Glass screens are preferred for quality but traditionally can't fold—though bendable glass exists.
Bendable glass was developed for fiber optic cables, allowing flexibility without breaking.
Some cables can bend 90 degrees, but the required thickness for foldability is unsuitable for phone screens.
Corning and other manufacturers are developing thin, foldable glass for phone displays.
Once perfected, foldable phones could achieve display quality comparable to current smartphones.
Output device: lets you send processed data out of your computer in the form of text, pictures, sounds, or video
Image outputs
Display screens show text, graphics, and videos.
Common screen types:
LCD (Liquid Crystal Display): Energy-efficient, lightweight, flat-panel monitor.
LED (Light-Emitting Diode): More energy-efficient than LCD; offers better color accuracy and thinner panels.
OLED (Organic Light-Emitting Diode): Uses organic compounds that light up with an electric current; does not require a backlight.
Advantages of OLEDs:
Thinner (as thin as 3 mm).
Brighter, more environmentally friendly, and power-efficient.
Longer battery life on portable devices compared to LEDs.
Widely used in smartphones and tablets.
Innovative OLED uses:
Transparent and flexible OLED screens under development.
Transparent screens display information while showing what’s behind the screen.
Potential applications: Translating street signs without a camera, immersive experiences
Display screens consist of millions of tiny dots called pixels.
Pixels create images when illuminated by light waves from a fluorescent panel behind the screen.
Pixels in 4K and 8K TVs/monitors are composed of four subpixels: yellow, red, blue, and green.
Some TVs further divide subpixels into upper and lower sections that adjust brightness independently.
LCD Monitors
Made of two or more sheets filled with a liquid crystal solution.
A fluorescent panel at the back generates light waves.
Electric current manipulates liquid crystals to block or allow light to pass.
This light manipulation forms images on the screen.
Colors on monitors result from various combinations of yellow, red, blue, and green subpixels.
Aspect ratio determines the width-to-height proportion of a monitor, traditionally 4:3 but now often 16:9 for HD video.
Resolution reflects the clearness or sharpness of the image, determined by the number of pixels; higher resolution provides sharper images.
Example of resolution: 5120 x 2880 pixels (native or maximum resolution), dictated by screen size and aspect ratio.
Refresh rate measures how frequently pixels are updated per second; higher refresh rates ensure smoother motion, important for gaming.
Larger screens can display more content and often support higher resolutions, such as a 27-inch monitor compared to a 21.5-inch monitor.
4K monitors (3840 x 2160 resolution) are adequate for most users.
Larger or multiple screens enable viewing of multiple documents or web pages simultaneously.
Ensure compatible video hardware/software when using large or multiple screens.
8K monitors and TVs have a resolution of 7680 x 4320 pixels.
Ultra HD (4K) devices have a resolution of 3840 x 2160 pixels, four times the pixels of original HD.
High-resolution devices require media providers to stream content in matching resolutions; check with your provider before purchasing.
HDTVs or projectors can display output to large groups.
Portable projectors are lightweight and suitable for business presentations.
Entertainment projectors with stereo speakers and multimedia connectors are ideal for home use.
Interactive whiteboards in classrooms and conference rooms pair with projectors, allowing touch input via pen, finger, or stylus.
Interactive whiteboards enable saving notes and annotations directly to the connected computer
Audio output
Portable devices include integrated speakers for basic audio playback and internet calls.
For higher audio quality or editing, consider a speaker system with subwoofers and surround-sound capabilities.
Surround-sound systems provide a 360-degree audio experience with multiple speakers and audio processing.
Wireless speaker systems allow easy connection to portable devices.
Headphones or earbuds can connect wirelessly or via the same jack used for external speakers.
Earbuds, which fit into ear canals, can cause hearing damage if used at excessive volumes—limit volume to protect hearing
Printers
Creates hard copies of text and graphics
Inkjet and laser
Inkjet printers are affordable, quiet, and produce high-quality printouts.
They spray tiny drops of ink onto paper, suitable for black-and-white text and color images.
High-end inkjet printers can create professional-quality photo prints when used with the right paper.
Ink options include replaceable cartridges or refillable ink tanks (e.g., Epson EcoTank).
Laser printers use laser beams and static electricity to apply toner, which is fused to the page with heat for permanent images.
Laser printers print faster and with higher quality than inkjets.
Black-and-white and color laser printers are affordable and economical for high-volume printing.
Color laser printers are often more cost-effective than inkjets when factoring in ink or toner expenses
ireless printers are ideal for printing from portable devices and home networks.
Wireless printers allow multiple users to print from different devices within a range of 300 feet.
Wi-Fi printers are faster than Bluetooth printers, but both have similar ranges.
Apple iOS devices use AirPrint to easily print to compatible wireless printers.
Non-Apple devices can print using apps provided by newer wireless printers.
All-in-one printers combine printing, scanning, copying, and faxing in a single device, using either inkjet or laser technology.
Large-format printers produce oversized images like banners, posters, and infographics with advanced color detail.
3D printers create three-dimensional objects layer by layer, typically using plastic filament and guided by CAD software.
3D printers are used in manufacturing consumer goods like toys and clothing.
Teraflops and gaming
Xbox Series X delivers 12 teraflops, and PlayStation 5 offers 10.28 teraflops.
FLOPS stands for floating-point operations per second.
Floating-point arithmetic is faster and more efficient than fixed-point arithmetic.
It enhances processing speed and generates superior graphics for complex games.
The GPU (graphics processing unit) handles graphics data and its power is measured in FLOPS.
A teraflop equals 1 trillion floating-point operations per second.
A GPU with 12 teraflops processes 12 trillion operations per second, enabling a superior gaming experience.
Morpheus
The University of Michigan developed a new CPU architecture called Morpheus.
Morpheus defends against hackers by randomly shuffling and encrypting parts of its code 20 times per second.
Vulnerabilities disappear milliseconds after being identified by hackers.
In a three-month DARPA and Department of Defense contest, no successful attacks were made on Morpheus.
Represents a potential breakthrough in computer defense against malicious attacks.
Right-click the Start button and select System to access the System About screen.
Gather information such as:
Windows version
Processor type and speed
Installed RAM
System type (32-bit or 64-bit)
Example details from System About screen:
Processor: Intel Core i7-2670QM, 2.20 GHz
RAM: 8.00 GB (7.80 GB usable)
System type: 64-bit OS, x64-based processor
Windows version: Windows 10 Home
Right-click the Start button and select File Explorer, then choose This PC to view storage device details.
To see more information about a specific item (e.g., the C: drive), right-click the item.
App inventor
Needs wifi, chrome browser, google account, and the MIT A12 Companion app
Build an app
Programming platform for apps on android devices
CPU and memory are the main components for processing, located on the motherboard.
Motherboard
Main circuit board of the computer.
Contains the CPU, memory (RAM), circuit boards, and expansion slots.
In desktops, located in the system unit (metal or plastic case with power source and storage devices).
In portable devices (laptops, tablets, phones), combined with the monitor and keyboard in a compact form.
Desktop motherboard features:
CPU socket (top center)
RAM slots (top right)
Ports for external connections (top left)
Expansion slots (bottom left and center)
Computer Memory (RAM)
Temporary storage for programs and data currently in use.
Faster than hard drives for reading and writing data.
Processor accesses RAM contents in nanoseconds for processing.
RAM consists of memory modules plugged into slots on the motherboard.
Volatile storage: data is erased when the device is powered off.
Permanent data storage requires saving to a hard drive, flash drive, or cloud storage.
Read-Only Memory (ROM)
Nonvolatile storage, retains data when powered off.
Stores permanent instructions required for startup.
Additional functionality on the motherboard
Integrated support for sound and video output in portable devices.
Wireless network interface modules for Wi-Fi connectivity.
Connectivity ports like USB and Thunderbolt.
Integrated GPS receivers for location tracking, used for:
Emergency services (e.g., 911 calls).
Location-dependent apps (e.g., Google Maps, Pokémon Go).
Desktop Motherboard features:
May include integrated features or use expansion cards.
Expansion Cards (Adapter Cards):
Circuit boards adding functionality, inserted into expansion slots.
Common cards:
Sound cards: Connect speakers and microphones.
Video cards: Connect monitors and enhance video output.
High-end gaming desktops use upgradeable expansion cards for advanced video and sound capabilities.
Importance of CPUs
Referred to as the "brains" of the computer.
Controls all computer functions and processes software commands.
Processor speed measurement
Measured in hertz (Hz).
Current CPUs operate in gigahertz (GHz), representing billions of operations per second (e.g., 3.8 GHz = 3.8 billion operations per second).
Factors affecting processor performance
Number of cores
Modern CPUs have multiple cores (e.g., 2, 4, 10), enabling parallel processing.
Multi-core processors run multiple programs simultaneously, improving efficiency.
Examples: Virus protection and operating systems can use separate cores, freeing others for applications like browsers or Excel.
Choosing the best processor
Intel CPUs are differentiated by generations (higher generation = newer and more powerful).
Websites like cpubenchmark.net help compare CPU performance.
Local storage devices
Hard drives
Primary permanent storage device for software and documents.
Internal hard drives reside within the system unit; capacities can reach 30 TB or more.
External hard drives offer similar storage but connect via a port.
Conventional vs. solid-state drives (SSD)
Conventional drives have moving parts, prone to failure.
SSDs have no moving parts, making them efficient, silent, cooler, and more durable.
Replacing a conventional drive with an SSD can improve older laptops' performance.
Drive bays
Desktop computers may have empty drive bays for additional drives.
Laptops typically require external drives or cloud storage for expansion.
Cloud storage
Stores files online for easy access across devices and collaboration.
Popular services: Google Drive, Microsoft OneDrive, Dropbox.
Files saved in cloud folders sync across devices with Internet access.
Free storage space varies; additional storage available for a fee.
Portable storage options
External hard drives
Portable, lightweight, with storage capacities of 16 TB or more.
Connect via USB ports.
Flash drives
Durable, no moving parts, use solid-state memory.
Compact and capable of storing up to 4 TB.
Ideal for backups and offline access to important files.
Cell phone storage
Modern phones use memory chips, not hard drives.
Some smartphones support storage expansion via micro SD cards.
Easy to install but not available on all phones (e.g., iPhones).
iPhone users rely on cloud storage to conserve space.
Ethical guidelines on computers (ten commandments of computer ethics)
Avoid causing harm to others when using computers.
Do not interfere with other people’s efforts at accomplishing work with computers.
Resist the temptation to snoop in other people’s computer files.
Do not use computers to commit theft.
Agree not to use computers to promote lies.
Do not use software (or make illegal copies for others) without paying the creator for it.
Avoid using other people’s computer resources without appropriate authorization or proper compensation.
Do not claim other people’s intellectual output as your own.
Consider the social consequences of the products of your computer labor.
Only use computers in ways that show consideration and respect for others.
US law supports certain ethical guidelines
Guideline 6: Violations are subject to copyright laws.
Guideline 4: Enforceable under federal and state larceny laws.
Some don’t have legal enforcement but require ethical interpretation
Guideline 7: unauthorized use of resources
Example: Using school-provided computers for non-coursework purposes, like running an online business.
Though not illegal, it misuses resources meant for learning and coursework.
Also violates Guidelines 2 and 10.
Ethical considerations will arise throughout various computer related scenarios
Green computing (Green IT): a movement promoting environmentally sustainable computing
Main goals
Reduce hazardous processes/materials in computing equipment production.
Promote recyclable/biodegradable materials for safe disposal.
Purchase energy-efficient products.
Use technology to reduce employee travel.
Minimize energy use and material consumption through shared computing resources.
Carbon footprint
Total greenhouse gases produced by a business (measured in tons of CO₂ equivalent).
Reducing emissions is essential for environmental health.
Shared computing resources
Consolidating resources (e.g., cloud storage) reduces energy and material consumption.
Example: One company managing resources for multiple others.
Individual participation
Everyone can contribute to green computing practices
Ports and peripheral devices
Ports enable data exchange between peripheral devices and the operating system.
Peripherals may connect wirelessly, but ports remain common for physical connections.
Common digital device ports
Thunderbolt ports
Connect up to six peripherals via one port.
Thunderbolt 4 supports transfer speeds up to 40 Gbps.
USB ports
Widely used for peripherals like keyboards, printers, mice, and external drives.
USB 4, the latest standard, uses USB-C connectors and supports 40 Gbps transfer rates.
USB-C is gradually replacing older USB connector types.
Connectivity ports
Ethernet ports
Resemble larger phone jacks.
Transfer data at speeds up to 10,000 Mbps.
Connect computers to cable modems or wired networks.
Audio and video ports
Audio: used for headphones, microphones, and speakers
Video: attach monitors or add external display
HDMI ports
Compact audio-video interface for HD video and uncompressed digital audio.
HDMI 2.1 supports up to 10K resolution.
Display ports
Developed for computer monitors.
DisplayPort 2 supports up to 16K resolution and 77.37 Gbps transfer rates.
Ideal for high-performance gaming setups.
Port usage
Port choice depends on device compatibility.
For new equipment, DisplayPort offers superior performance, especially for gaming.
Charging a computer battery
Power supply comes as a brick with a cord to charge the battery.
Transforms wall voltage to the appropriate voltage for the battery or computer chips.
Desktop computers have an internal power supply.
Biggest battery drainers
Display: LCD and OLED backlights consume the most power.
Wi-Fi and Bluetooth Adapters: Constant scanning drains power.
Plugged-in Peripherals: Draw power from the computer.
Apps: Background syncing and alerts significantly drain the battery.
Android: Check Settings > Device > Battery or Power > Battery Use.
iOS: Check Settings > Battery for usage details.
Windows: Check Settings > System > Power & battery > Battery usage.
Solutions
Uninstall rarely used apps with high power consumption.
Disable sync and alerts in frequently used apps when the battery is low.
Shutting down a computer
Use Shut down in power options for a complete power-off.
If unresponsive, hold the power button to force shutdown.
Sleep mode
Keeps documents and apps in RAM for quick access when resumed.
Saves energy and prolongs battery life.
Activate Sleep: Start menu > Power icon > Sleep option.
Resume by pressing a key or power button.
Restart option
Warm Boot: Restart while powered on to fix unresponsive software or apply updates.
Cold Boot: Power on from a completely off state; takes longer than a warm boot.
Turning off the computer regularly
Arguments Against: Frequent on-off cycles may stress components due to heating/cooling expansion.
Arguments For: Environmentally friendly and cost-effective to shut down when not in use.
Power management settings
All modern operating systems (Windows, Android, iOS, macOS) include power-management settings to conserve power.
Hard drives and monitors can automatically shut down after a short idle period.
These settings help conserve power and battery life without needing to turn devices off completely.
Windows power settings
Access power settings: Right-click Start icon > Settings > System > Power & battery > Screen and sleep.
Options for power button or lid actions: Choose Sleep, Hibernate, or Shut down.
Hibernate: Stores data on the hard drive instead of RAM and powers off the computer, saving more battery than Sleep.
Sleep: Good for short breaks, keeps data in RAM for quick access.
Customize to have the computer Sleep when the lid closes and Hibernate when pressing the power button for flexibility.
Monitoring coral reef technology
Monitoring coral reefs is vital for assessing climate change and pollution effects.
Fish population and diversity are key health indicators of reefs.
Current reef monitoring is labor-intensive, relying on human divers.
Divers are limited by time underwater and the number of dives.
Human presence can disrupt fish activity and skew results.
Intel and Accenture partnered with scientists in the Philippines to create automated reef monitoring.
They developed artificial reefs made of concrete with embedded video cameras.
Accenture’s AI platform analyzes fish activity, classifies, and photographs fish.
Data is transmitted via Wi-Fi or 4G from a buoy to onshore researchers.
This system allows real-time, undisturbed analysis of the reef.
Artificial reefs also help repair damaged reefs, as coral adheres to the concrete.
The technology will soon be implemented in reefs worldwide.
Computers once required electronics and engineering expertise to build.
Today, components are accessible for novices to build their own computers.
Many gamers build computers to get desired components and save money.
Online resources, including step-by-step guides and parts lists, can help.
Key components for building a computer:
CPU: Central to processing; choose from AMD (Ryzen, Threadripper) or Intel (i9, 9th gen+).
Motherboard: The circuit board connecting components; choose based on CPU compatibility.
Graphics Card (GPU): Crucial for gaming; choose high-quality GPUs from AMD or Nvidia.
Memory (RAM): More RAM is better; 32 GB is good for most gaming systems.
Storage: SSDs offer better speed and less heat than conventional hard drives.
Power Supply (PSU): Provides power; select based on component wattage requirements.
System Unit (Case): Holds components; size and cooling features vary.
Cooling Devices: Essential for managing heat; use fans or dedicated CPU coolers.
Monitor: High-resolution monitor is necessary; 4K and high refresh rates for better performance.
Mouse: Choose based on gaming style; brands like Logitech, Corsair, and Razer offer reconfigurable options.
Keyboard: Ranges from basic to lighted models; test to find the right fit.
Ergonomics: The science of designing machines and furniture to avoid discomfort or injury during use, particularly in computing setups.
Long-term computer use can lead to repetitive-stress injuries like carpal tunnel syndrome and tendonitis, especially for teens spending 9+ hours daily.
Injury prevention
Monitor Placement: Position at least 25 inches from eyes, at eye level or 15-20 degrees below line of sight.
Adjustable Chair: Ensure feet touch floor, lumbar support is provided, and use a pillow if necessary.
Proper Typing Position: Keep wrists flat, forearms parallel, avoid resting wrists on the keyboard; use ergonomic keyboards if needed.
Breaks: Change position, stretch hands/fingers, rest eyes regularly.
Lighting: Ensure adequate lighting, eliminate glare, use ring light for video calls.
Mobile device ergonomics: Challenges like neck strain from using laptops on laps. Guidelines for reducing injuries while using smartphones, media players, tablets, and laptops.
Prevention: Reduce message length, lower sound volume, take breaks, maintain proper lighting, adjust screen size, use laptop cooling pads.
Assistive technologies: Devices to help individuals with disabilities:
Voice recognition: For users with visual impairments or typing difficulties.
Large Key Keyboards: For users with mild visual impairments.
Trackballs: For users with limited motor control, can be used with one finger or mounted on various surfaces.
Head-mounted pointing devices: For users with restricted arm motion, controlled by head movements and switches operated by hands, feet, or mouth.
SUMMARY
Understanding Your Computer
Objective 2.1 Describe the four main functions of a computer system and how they interact with data and information.
The computer’s four major functions are: (1) input: gather data or allow users to enter data; (2) process: manipulate, calculate, or organize that data; (3) output: display data and information in a form suitable for the user; and (4) storage: save data and information for later use.
Data is a representation of a fact or idea. The number 3 and the words televisions and Samsung are pieces of data.
Information is data that has been organized or presented in a meaningful fashion. An inventory list that indicates that three Samsung televisions are in stock is processed information. It allows a retail clerk to answer a customer query about the availability of merchandise. Information is more powerful than raw data.
Objective 2.2 Define bits and bytes, and describe how they are measured, used, and processed.
To process data into information, computers need to work in a language they understand. This language, called binary language, consists of two numbers: 0 and 1. Each 0 and each 1 is a binary digit or bit. Eight bits comprise one byte.
In computers, each letter of the alphabet, each number, and each special character consists of a unique combination of eight bits (one byte)—a string of eight 0s and 1s
KEY TERMS
2-in-1 PC
3D printer
all-in-one computer
all-in-one printer
aspect ratio
assistive (adaptive) technology
binary digit (bit)
binary language
bit
Bluetooth
byte
central processing unit (CPU, or processor)
Chromebook
cloud storage
cold boot
computer
connectivity port
data
desktop computer
digital convergence
display screen (monitor)
DisplayPort
embedded computer
ergonomics
expansion cards (or adapter cards)
flash drive (jump drive, USB drive, or thumb drive)
flatbed scanner
gigabyte (GB)
green computing (green IT)
hard drive
Hardware
hibernate
high-definition multimedia interface (HDMI) port
information
inkjet printer
input device
integrated circuit (chip)
intelligent personal assistant
interactive whiteboard
kilobyte (KB)
laptop (or notebook) computer
large format printer
laser printer
light-emitting diode (LED)
liquid crystal display (LCD)
mainframe
mechanical keyboard
megabyte (MB)
microprocessor
motherboard
mouse
nonvolatile storage
operating system (OS)
organic light-emitting diode (OLED) display
output device
peripheral device
petabyte (PB)
pixel
port
power supply
processing
random access memory (RAM)
read-only memory (ROM)
refresh rate
resolution
sensor
Sleep mode
smartphone
software
solid-state drive (SSD)
sound card
stylus
supercomputer
surround-sound system
system unit
Tablet computer
terabyte (TB)
Thunderbolt port
touch pad (trackpad)
touch screen
ultrabook
universal serial bus (USB) port
video card
voice recognition
volatile storage
warm boot
webcam
Binary Language
Computers work only with numbers (not words). To process data, computers need to work in a language they understand. This language, called binary language, consists of just two digits: 0and 1.
Everything a computer does, such as process data or print a report, is broken down into a series of 0s and 1s. Each 0 and 1 is a binary digit, or bit for short.
Eight binary digits (or bits) combine to create one byte.
In computers, each letter of the alphabet, each number, and each special character (such as the @ sign) consists of a unique combination of eight bits, or a string of eight 0s and 1s.
So, for example, in binary (or computer) language, the letter K is represented as 01001011. This equals eight bits, or one byte.
Units of Measure: KB, MB, GB, and Beyond
Bits and bytes not only are used as the language that tells the computer what to do but also are what the computer uses to represent the data and information it inputs and outputs. Word processing files, digital pictures, and even software are represented inside a computer as a series of bits and bytes.
To make it easier to measure the size of these files, larger units of measure are used.
A kilobyte or KB is approximately 1,000 bytes, a megabyte or MB is about one million bytes, and a gigabyte or GB is about one billion bytes.
Today, personal computers store terabytes (TB) of data (about 1 trillion bytes), and many business computers can store up to a petabyte (PB) of data (1,000 terabytes).
Computer Processing
Strictly defined, a computer is a data processing device that performs four major functions, including processing data into information.
Processor speed is measured in units of hertz (Hz). Hertz means “machine cycles per second.” A machine cycle is the process of the CPU getting the data or information from RAM and decoding the instructions into something the computer can understand. After decoding, the CPU executes and stores the results back into system memory as the last step of the machine cycle.
Besides processor speed, other considerations such as the number of cores a processor has, as well as cache memory and front side bus (FSB), determine the overall power of the processor.
Data vs. Information
Data is the representation of a fact, a figure, or an idea. Data can be a number, a word, a picture, or even a recording of sound. Computers are excellent at processing data into information.
Information is data that has been organized or presented in a meaningful fashion. Here, the data supplied to the computer (name, phone number, address, photo) has been processed appropriately so that it could be printed on an ID card.
This organized output of data on an ID card is useful information. This information can be stored as digital data on the computer for later use.
In order to process data into information, computers use binary language, which consists of two digits: 0 and 1. Each 0 and 1 is a binary digit, or bit for short. In computers, each letter, number, or special character consists of a unique combination of eight bits, or one byte. Kilobytes, megabytes, gigabytes, terabytes, and petabytes are amounts of bytes. Strictly defined, a computer is a data processing device that performs four major functions, including processing data into information.
Cheat Sheet
A. Bits, Bytes, and Binary Language
Byte: A byte is a term used to represent 8 bits of data. One byte can hold about one letter of the alphabet, one number, or one special character.
Bit: A bit is short for binary digit. Each bit represents a 0 or a 1.
Binary Language: To process data, computers use binary language, which consists of just two digits: 0 and 1. Everything a computer does is broken down into a series of 0s and 1s. Each 0 and 1 is a binary digit, or bit for short. In computers, each letter of the alphabet, each number, and each special character (such as the @ sign) consists of a unique combination of eight bits, or a string of eight 0s and 1s.
B. Kilobytes, Megabytes, Gigabytes, and Beyond
Kilobyte (KB): Approximately 1,000 bytes.
Megabyte (MB): About 1 million bytes.
Gigabyte (GB): About 1 billion bytes.
Terabyte (TB): About 1 trillion bytes
Petabyte (PB): About 1,000 terabytes
C. Computer Processing
Processor Speed: Processor speed is measured in units of hertz (Hz). Hertz means “machine cycles per second.” A machine cycle is the process of the CPU getting the data or information from RAM and decoding the instructions into something the computer can understand.
Data: The representation of a fact, a figure, or an idea. Data can be a number, a word, a picture, or even a recording of sound.
Information: Data that has been organized or presented in a meaningful fashion.
Binary digit or bit: A digit that corresponds to the on and off states of a computer’s switches. A bit contains either a value of 0 or 1.
Binary language: The language computers use to process information consisting of only the digits 0 and 1.
Byte: Eight binary digits (or bits).
Computer: A data processing device that performs four major functions: gathers inputs, processes, outputs, and stores.
Data: Numbers, words, pictures, or sounds that represent facts, figures, or ideas.
Gigabyte (GB): About 1 billion bytes.
Hertz (Hz): Machine cycles per second
Information: Data that has been organized or presented in a meaningful fashion.
Kilobyte (KB): Approximately 1,000 bytes.
Megabyte (MB): About 1 million bytes.
Petabyte (PB): Approximately 1,000 terabytes.
Processing: Manipulating, calculating, or organizing data into information.
Terabyte(TB): About 1 trillion bytes.
Understanding Binary Numbers
Binary numbers are based on a system of only 2 digits: 0 and 1.
Each binary digit is called a bit.
Binary Basics
Every kind of information a computer can store is encoded into a binary code.
A computer can also read the binary code and output alpha-numeric characters, graphics, and more.
Base Systems
Each base system depends on place value to give meaning to the digits in a number.
A 3-digit decimal number has a hundreds (102), tens (101) and ones (100) place.
A 3-digit hexadecimal number has a two hundred fifty sixes (162), sixteens (161), and ones (160) place.
Exploring Base Conversion
Humans use decimal (Base 10) numbers
Computers use binary (Base 2)
Hexadecimal (Base 16) numbers are used to represent larger numbers with fewer digits
Conversion in Action
Colors on a computer display are represented using a red, green, and blue (RGB) system.
Each of the three colors can have a value from 0 to 255.
The higher the number, the brighter the light for that color shines.
Summary
Objective 1: Describe the nature of binary numbers.
Binary numbers are based on a system of only 2 digits: 0 and 1.
Each binary digit is called a bit.
Objective 2: Describe the things binary numbers can represent.
Every kind of information a computer can store is encoded into a binary code.
A computer can also read the binary code and output alpha-numeric characters, graphics, sounds, and colors.
Objective 3: Describe how base systems function.
Each base system depends on place value to give meaning to the digits in a number.
The digit to the far right always has a place value of 1.
A three-digit decimal (base 10) number has a hundreds (102), tens (101), and ones (100) place.
Objective 4: Explain how colors are represented in number systems.
Colors on a computer display are represented using a red, green, and blue (RGB) system.
Each of the three colors can have a value from 0 to 255.
Smartphones Are Computers
Hardware: CPU and storage capabilities
Input and output devices: touch-sensitive screen. microphone, keypad, camera
Ports
Software: OS and apps
Sensors
Connectivity
Internet
Cellular signal
Wi-Fi
Bluetooth
NFC
Ports
Memory and Storage
Up to 256 GB internal memory
Some support internal micro SD cards
Some support external SD cards
Operating Systems
iPhone iOS
Google Android
Cloud Storage
Backup
Easy
Safe
Photo storage
Instant
Synchronized across multiple devices
Intelligent Assistants
Siri (iOS devices)
Google Assistant (Android devices)
AI assistants
Support voice commands to send texts, set reminders, change phone settings
Gather information you need based on your location or task lists
Global Positioning System (GPS)
Powerful navigational aid
System of satellites
Built and operated by the U.S. Department of Defense
Objective 1: Describe why smartphones are complete computer systems
Smartphones include a CPU, operating system, storage, ports, and input and output devices as well as many kinds of sensors.
Objective 2: Describe major mobile operating systems.
There are two major mobile operating systems: iOS and Android.
Objective 3: Explain the advantages of integrated cloud storage.
Mobile devices have integrated cloud storage solutions that provide users with access to files stored in the cloud.
Objective 4: Understand how artificial intelligence assists smartphone users.
Smartphones now use artificial intelligence tools like Siri and Google Assistant.
They use sensor input from GPS, accelerometers, and biometric sensors.
