New Perspectives on Computer Concepts: Digital Devices Study Guide

Device Basics

Definition of a Computer: At its core, a computer is a multipurpose device that accepts input, processes data, stores data, and produces output, all according to a series of stored instructions. * Input: Whatever is typed, submitted, or transmitted to a computer. * Output: The result produced by a computer. * Processing: Computers process data by performing calculations, modifying documents and pictures, drawing graphs, and sorting lists of words or numbers. This is handled by the Central Processing Unit ( $CPU$ ).
Software and Programs: * Computer Program: The instructions that tell a digital device how to carry out processing tasks. * Software: Programs that set up a computer to do a specific task. When a computer "runs" software, it performs the instructions. * Stored Program Concept: This means a series of instructions for a computing task can be loaded into a computer’s memory. This allows a device to switch easily between tasks (e.g., from word processing to editing photos). It is the single most important characteristic distinguishing computers from simpler digital devices like digital clocks, calculators, and cameras.
Types of Software: * Application Software: A set of computer programs that helps a person carry out a task (e.g., Microsoft Word, PowerPoint). * System Software: Primary purpose is to help the computer monitor itself to function efficiently (e.g., Operating Systems like iOS, Windows, Android). * Development Tools: Used for creating software applications, websites, operating systems, and utilities.
Circuits and Chips: * Digital Electronics: Represent data bits as electrical signals traveling over circuits. * Integrated Circuit ( $IC$ ): A set of microscopic electronic circuits etched onto a thin slide of semiconducting material. Also commonly called a computer chip, microchip, or chip. * Semiconductors: Materials such as silicon and germanium with properties between a conductor (like copper) and an insulator (like wood). * System Board: Also known as the motherboard or main board. It houses all essential chips and provides connecting circuitry between them.
Form Factors and Components: * Form Factor: Refers to the size and dimensions of a device or components. * System Unit: The part of a digital device that holds the system board. * Popular Form Factors: Component, clamshell, and slate.
Maintenance and Care: * Four Components Requiring Maintenance: System unit, keyboard, screen, and battery. * Cleaning Guidelines: * Don't use harsh cleaning products; follow manufacturer recommendations. * Never immerse a device in liquid. * Do not allow cleaning agents to drip on keyboards or touchpads. * Do not spray cleaning agents directly on the device; spray onto a cleaning cloth first. * System Unit Maintenance: Keep it clean, prevent overheating, shield from damage, and protect from electrical surges (only plug into surge-protected outlets). Use a low vacuum setting for fan vents. * Touchscreens: Often made of Gorilla Glass (scratch/crack resistant) with an oleophobic coating to repel oils. Clean periodically to remove bacteria. * Battery Care: Most devices use Lithium-ion ( $Li-ion$ ) batteries. * Charge when the low battery indicator appears. * Avoid totally discharging the battery. * Remove from the charger when fully charged. * Turn off the device if it becomes hot to the touch. * Disable unused apps and use airplane mode in areas with no cell coverage to save power.

Device Options

Enterprise Computers: The most powerful computers, used by businesses and government agencies to service many simultaneous users at fast speeds. * Supercomputers: Fastest in the world at the time of construction; used for complex tasks like breaking codes, modeling weather, and simulating nuclear explosions. * Mainframes: Large, expensive computers capable of processing data for hundreds or thousands of users; circuitry is usually housed in a closet-sized cabinet. * Servers: Provide data to other computers in a network (e.g., Google search results). Typically the size of a desk drawer and mounted in racks.
Personal Computers ( $PC$ ): Designed to meet the computing needs of an individual. Types include: * Desktops: Fit on a desk, run on wall outlet power, typically have a separate keyboard and monitor. * Portables: Run on battery power with components in a single case. * Laptops: Also called notebook computers; utilize a clamshell design. * Tablets: Feature a touch-sensitive screen. "Slate" tablets (like the iPad) lack physical keyboards. * Smartphones: Mobile devices with tablet-like features and telecommunications capabilities.
Niche Devices: Devices containing a microprocessor for specific tasks. * Raspberry Pi: A full computer system slightly larger than a deck of cards. * Game Consoles: For playing computer games. * Portable Media Players: Handheld devices for music/video (e.g., iPod Touch). * Smartwatches: Include cameras, GPS, fitness trackers, and cell phone features. * Activity Trackers: Monitor steps and heart rate. * Smart Speakers: Voice-command devices for search and home control. * Smart Appliances: Modern home goods controlled by integrated circuits called microcontrollers.
Choosing a Digital Device: * Device Platforms: Computers that use the same software are "compatible" or have the same platform. Compatibility is determined by the Operating System. * Budget Categories: * Smartphones: $\$200$ to $\$900$ . * Tablets: $\$200$ to $\$1,500$ . * Desktops/Laptops: Under $\$500$ , $\$500$ to $\$1,200$ , and above $\$1,200$ . * Usage-Based Recommendations: * General Use (Email/Web): Mid-priced laptop. * Small Business Accounting: Specific business systems. * Gaming: Fastest processor and graphics card available, or a console. * Video Editing/Publishing: Fast processor, high hard disk capacity, large screen, and memory-loaded graphics card. * Special Needs: Adaptive equipment like voice synthesizers.

Processors and Memory

Microprocessors: Integrated circuits designed to process instructions. * x86 Standard: Derived from the Intel $8086$ chip family; includes Intel Core i3, i5, i7, and AMD Radeon/Ryzen. * ARM Technology: Designed by ARM Holdings (founded by Acorn, Apple, and VLSI); used in iPhones, iPads, Mac computers, and Android devices. Known for energy efficiency.
How Processors Work: * Instruction Set: A collection of preprogrammed activities/actions a microprocessor can perform. * Machine Language: Programs converted into binary strings that the microprocessor understands. * Arithmetic Logic Unit ( $ALU$ ): Performs arithmetic operations (addition, subtraction). Uses registers to hold data being processed. * Control Unit: Fetches instructions. The instruction pointer holds the memory address of the next instruction. * Instruction Cycle: The process of executing a single instruction: Fetch -> Interpret -> Execute -> Move to next instruction.
Performance Factors: * Clock Speed: Measured in Gigahertz ( $GHz$ ), meaning billions of cycles per second. A cycle is the smallest unit of time for a processor. * Multi-core Processor: Contains circuitry for more than one processing unit. * Processing Techniques: * Serial Processing: Completes one instruction before starting another. * Pipeline Processing: Begins executing an instruction before the previous one is finished. * Parallel Processing: Executes multiple instructions at once (standard in multi-core chips). * CPU Cache: High-speed memory for rapid data access. * Word Size: Number of bits handled at one time; limits accessible memory. * RISC vs. CISC: Reduced Instruction Set Computer ( $RISC$ ) is faster but requires more instructions per task. ARM is based on RISC.
Memory (RAM and ROM): * Random Access Memory ( $RAM$ ): Temporary holding area for data, instructions, and the OS. Uses capacitors to hold bits. Most RAM is volatile (requires power). * Read-only Memory ( $ROM$ ): Single integrated circuit on the system board containing the boot loader, which tells the device how to start. ROM is non-volatile. * Flashing ROM: Changing ROM contents for repairs, user modifications, forensics, or updates.

Storage

Storage Basics: Components designed to hold data permanently. * Selection Criteria: Durability (resistance to damage), Dependability (mean time between failures), Speed (data transfer rate), Capacity ( $GB$ or $TB$ ), and Cost ( $per\,GB$ ).
Magnetic Storage Technology: Foundation for Hard Disk Drives ( $HDD$ ). Data is represented by magnetizing microscopic particles on platters (aluminum or glass disks coated with iron oxide). A read-write head mechanism senses or changes polarities. * Access Time: Average time to locate and read data.
Optical Storage Technology: CDs and DVDs. Data is represented as light and dark spots. A laser beam is reflected and converted into $0$ s and $1$ s. * CD (Compact Disc): Capacity of $650\,MB$ to $700\,MB$ . * DVD (Digital Video Disc): Capacity of $4.7\,GB$ (single-sided) to $8.5\,GB$ (double-layer). * Categories: Read-only ( $ROM$ - 100 yr life), Recordable ( $R$ - 100 yr life), Rewritable ( $RW$ - 30 yr life).
Solid State Storage Technology: Also called flash memory. Uses non-volatile, erasable, rewritable circuitry. * Memory Card: Flat medium for cameras/media players. * Solid State Drive ( $SSD$ ): Substitute for a hard disk drive. * USB Flash Drive: Portable device with a built-in connector.
Cloud Storage: Internet-based remote storage (e.g., iCloud, OneDrive, Google Drive, Dropbox). * Pros: Inexpensive, convenient, allows synchronization between devices. * Cons: Security/privacy risks (hackers/government spying), service outages, and potential discontinuation of service.
Backup and Recovery: * What to Back Up: Data files (photos, documents), operating system, software, and settings/profiles. * Windows Tools: Recovery drive (for diagnosis), Copy command, File History (automated syncing of data folders), and System Image (bit-for-bit copy of the entire hard disk). * macOS Tools: Time Machine (comprehensive hard disk backup). * iOS Tools: Finder, iTunes, or iCloud.

Input and Output

Peripheral Devices: Classified as input, output, or mixed.
Expansion Ports: Expand options for input/output. Includes USB, VGA, HDMI, DVI, DisplayPort, Thunderbolt, and Ethernet. A USB hub can be used to add more ports.
Bluetooth: Low-power wireless technology ideal for mobile peripherals like headsets.
Device Driver: Software that helps a peripheral establish communication with the host device (e.g., driver for an HP printer).
Display Devices: * Liquid Crystal Display ( $LCD$ ): Filters light through liquid crystal cells. * Quality Factors: Screen size (diagonal measurement), Response rate (black to white to black speed), Dot pitch ( $dp$ - distance between crystals), and Resolution (horizontal/vertical pixels). * Graphics Circuitry: * Integrated Graphics: Built into the system board. * Dedicated Graphics: Mounted on a separate graphics card (video card). * Graphics Processing Unit ( $GPU$ ): Integrated circuit for processing and storing images before display.
Printers: * Ink Jet: Sprays ink through a nozzle-like head. * Laser: Paints dots of light on a drum and uses electrostatically charged ink.
Internet of Things ( $IoT$ ): A network of sensors that collect data to improve environments. * Components: Sensor(s), power source, transmitter, and antenna. * IMU Sensors: Include accelerometers, gyroscopes, and magnetometers.
Autonomous Vehicles: Use sense-plan-act algorithms to take over control from humans. * Lidar (Light Detection and Radar): Key input using laser range finders. Range is about $650\,ft$ ( $200\,m$ ). Maps objects in a $65\,ft$ radius. * Radar: Detects metallic objects using sound waves. * GPS: Use satellites for location; accurate to about $10\,ft$ . * Infrared: Senses heat signatures of people/animals. * Internal Navigation Systems ( $INS$ ): Use gyroscopes and accelerometers to track movement when GPS is blocked. * Cameras: Used with image recognition software for road signs and signals.

Icebreaker & Discussion Questions

Icebreaker Poll Items: Raspberry Pi, game console, portable media player, smartwatch, activity tracker, smart speaker, smart appliance.
Knowledge Check Answers: * The programming language consisting of binary strings is Machine Language. * The steps of the computer instruction cycle are: Fetch an instruction, interpret the instruction, execute the instruction, move to the next instruction (repeat). * A functional computer's read-only memory stores the boot loader.
Activity 2.3 Discussion Topics: * The IPOS model of computing activities. * Characteristics distinguishing enterprise from personal computers. * Major factors impacting microprocessor performance. * Recovering from main storage failure using backups. * Expected expansion ports on modern laptops and the flow of data.