Glossary
Abstraction: To take a relatively complex system and simplify it for our use
Algorithm: A series of steps that solves specific problems
ASCII: The oldest character encoding standard used is ASCII. It represents the English alphabet, digits, and punctuation marks
Binary system: The communication that a computer uses is referred to as binary system, also known as base-2 numeral system
Byte: A group of 8 bits
Character encoding: Is used to assign our binary values to characters so that we as humans can read them
Computer: A device that stores and processes data by performing calculations
Cryptography: The overarching discipline that covers the practice of coding and hiding messages from third parties
Decimal form- base 10 system: In the decimal system, there are 10 possible numbers you can use ranging from zero to nine
Digital divide: The growing skills gap between people with and without digital literacy skills
Information technology: The use of digital technology, like computers and the internet, to store and process data into useful information
Linux OS: Linux is one of the largest an open source operating system used heavily in business infrastructure and in the consumer space
Logic gates: Allow transistors to do more complex tasks, like decide where to send electrical signals depending on logical conditions
Open source: This means the developers will let other developers share, modify, and distribute their software for free
PDA (Personal Digital Assistant): Allows computing to go mobile
Punch cards: A sequence of cards with holes in them to automatically perform calculations instead of manually entering them by hand
RGB model: RGB or red, green, and blue model is the basic model of representing colors
UTF-8: The most prevalent encoding standard used today
Address bus: Connects the CPU to the MCC and sends over the location of the data, but not the data itself
ATA: The most common interface that hard drives use to connect to our system
ATX (Advanced Technology eXtended): The most common form factor for motherboards
Backward compatible: It means older hardware works with newer hardware
Bios (Basic Input Output Services): The BIOS is software that helps initialize the hardware in our computer and gets our operating system up and running
BYOD (Bring Your Own Device): Refers to the practice of allowing people to use their own personal devices for work
Cache: The assigned stored location for recently or frequently accessed data; on a mobile app it is where anything that was changed or created with that app is stored
Charge cycle: One full charge and discharge of a battery
Chipset: It decides how components talk to each other on our machine
Clock cycle: When you send a voltage to the clock wire
Clock speed: The maximum number of clock cycles that it can handle in a set in a certain time period
Clock wire: When you send or receive data, it sends a voltage to that clock wire to let the CPU know it can start doing calculations
CPU: Central processing unit
CPU sockets: A CPU socket is a series of pins that connect a CPU’s processor to the PC’s motherboard
Data sizes: Metrics that refer to data sizes including bit, byte, kilobyte, kibibyte, and megabyte
DDR SDRAM (Double Data Rate SDRAM): A type of RAM that is faster, takes up less power, and has a larger capacity than earlier SDRAM versions
Desktop: The main screen where we can navigate our files, folders, and applications
DIMM: Dual Inline Memory Module
Display port: Port which also outputs audio and video
DRAM: Dynamic Random Access Memory
Drivers: The drivers contain the instructions our CPU needs to understand external devices like keyboards, webcams, printers
DVI: DVI cables generally just output video
Electrostatic discharge: Electrostatic discharge is a sudden and momentary flow of electric current between two electrically charged objects caused by contact, an electrical short or dielectric breakdown
External Data Bus (EDB): It’s a row of wires that interconnect the parts of our computer
Factory reset: Resetting a device to the settings it came with from the factory
Form factor: A mathematical way to compensate for irregularities in the shape of an object by using a ratio between its volume and height
Hard drive: It is a long term memory component that holds all of our data, which can include music, pictures, applications
Hardware: External or internal devices and equipment that help you perform major functions
HDD (Hard disk drive): Hard disk drives, or HDDs, use a spinning platter and a mechanical arm to read and write information
HDMI: A type of cable that outputs both video and audio
Heatsink: It is used to dissipate heat from our CPU
Instruction set: A list of instructions that our CPU is able to run
ITX (Information Technology eXtended): A form factor for motherboards that is much smaller than ATX boards
Land Grid Array (LGA): It is a type of CPU socket that stick out of the motherboard
Lightning adaptor: One of the standard power, data and display connector types used in mobile devices
Mb/s: megabit per second, which is a unit of data transfer rate
Memory controller chip (MCC): A bridge between the CPU and the RAM
Micro display port: One of the standard power, data and display connector types used in mobile devices
Micro HDMI: One of the standard power, data and display connector types used in mobile devices
Micro USB: One of the standard power, data and display connector types used in mobile devices
Mini HDMI: One of the standard power, data and display connector types used in mobile devices
Mini USB: One of the standard power, data and display connector types used in mobile devices
Motherboard: The body or circulatory system of the computer that connects all the pieces together
Northbridge: interconnects stuff like RAM and video cards
NVMe (NVM Express): interface standard which allows greater throughput of data and increased efficiency
Overclocking: it increases the rate of your CPU clock cycles in order to perform more tasks
PCI Express: Peripheral Component Interconnect Express
Peripherals: the external devices which we connect to our computer that add functionality, like: a mouse, a keyboard, and a monitor
Pin Grid Array (PGA): CPU socket where the pins are located on the processor itself
Ports: Connection points that we can connect devices to that extend the functionality of our computer
POST (Power On Self Test): It figures out what hardware is on the computer
Power supply: Converts electricity from our wall outlet onto a format that our computer can use
Programs: Basic instructions that tell the computer what to do
RAM: Random Access Memory
Registers: An accessible location for storing the data that our CPU works with
Reimaging: The process of reimaging involves wiping and reinstalling an operating system using a disk image which is a copy of an operating system
Return merchandise authorization (RMA): The process of receiving returned merchandise and authorizing a refund
ROM chip (Read Only Memory): A read-only memory chip where the BIOS is stored
RPM: Revolutions per minute
Safe operating temperature: The temperature range in which rechargeable batteries must be kept in order to avoid demanage
SATA: The most popular serial ATA drive, which uses one cable for data transfers
SDRAM: It stands for Synchronous DRAM, this type of RAM is synchronized to our systems’ clock speed allowing quicker processing of data
SOC (System On a Chip): Packs the CPU, Ram, and sometimes even the storage onto a single chip
Southbridge: It maintains our IO or input/output controllers, like hard drives and USB devices that input and output data
SSD: Solid State Drive
Standoffs: Used to raise and attach your motherboard to the case
Thermal paste: A substance used to better connect our CPU and heat sink, so the heat transfers from to the other better
Type-C connector: A type of USB connector meant to replace many peripheral connections
UEFI: United Extensible Firmware Interface
USB (Universal Serial Bus): A connection standard for connecting peripherals to devices such as computers
USB-C adapter: One of the standard power, data and display connector types used in mobile devices
Android: A mobile operating system based on Linux
Application: A computer program designed for a specific use
BIOS/UEFI: A low-level software that initializes our computer’s hardware to make sure everything is good to go
Block storage: It improves faster handling of data because the data isn’t stored in one long piece but in blocks, so it can be accessed more quickly
Boot: To start up a computer
Bootloader: A small program that loads the operating system
Chrome OS: A Linux-based operating system designed by Google
Command Line Interface (CLI): A shell that uses text commands to interact with the operating system
Computer file: Data that we store and a file can be anything, a word document, a picture, a song, literally anything
Data blocks: Data that can be broken down into many pieces and written to different parts of the hard disk
Distributions: Some common Linux distributions are Ubuntu, Debian, and Red Hat
Etcher.io: A tool you can use to load an install image onto your USB device and make it bootable
File extension: The appended part of a filename that tells us what type of file it is in certain operating systems
File handling: A process of storing data using a program
File system: A system used to manage files
Finder: The file manager for all Macs
Folders/Directories: Used to organize files
Hardware resource deficiency: It refers to the lack of system resources like memory, hard drive space, et cetera
HFS+/APFS: HFS+ is a journaling system developed by Apple Inc. and APFS is another but more encrypted Apple journaling system
Hostname: Used to identify the computer when it needs to talk to other computers
Input/Output device: A device that performs input and output, including monitors, keyboards, mice, hard disk drives, speakers, bluetooth headsets, webcams, and network adapters
Install image: A downloadable operating system image used to install an operating system on a device
I/O management: Anything that can give us input or that we can use for output of data
iOS: A mobile operating system developed by Apple Inc.
Kernel: The main core of an operating system that creates processes, efficiently schedules them, and manages how processes are terminated
Logs: Files that record system events on our computer
Mac OS: Apple’s operating system
Memory management: One of the functions that a kernel performs; it optimizes memory usage and make sure our applications have enough memory to run
Metadata: Tells us everything we need to know about a file, including who created it, when it was last modified, who has access to it, and what type of file it is
Microsoft Terminal Services Client: A client program used to create RDP connections to remote computers
Open SSH: The most popular program to use SSH within Linux
Operating system: The whole package that manages our computers resources and lets us interact with it
PC: Personal computer, which technically means a computer that one person uses
Plink (PuTTY Link): A tool built into the command line after PuTTY is installed that is used to make remote SSH connections
Powershell: A shell (program that interprets text commands) for Windows
Power user: Above average computer users
Process management: The capacity to manage the many programs in a system – when to run them, the order they run in, how many resources they take up, how long they run, etc.
Qwiklabs: An online platform which provides training in cloud services
Remote connection: The ability to connect an authorized person to a computer or network remotely; allows us to manage multiple machines from anywhere in the world
Remote Desktop Protocol (RDP): A secure network communication protocol developed by Microsoft that allows a user to connect to another device remotely
Scalability: The measure of a system’s ability to increase or decrease in performance and cost in response to varying loads in system processing demands
Shell: A program that interprets text commands and sends them to the OS to execute
SSH (Secure shell): A protocol implemented by other programs to securely access one computer from another.
SSH authentication key: A secure authentication method for accessing a computer from other device
SSH client: A program you must have installed on your device in order to establish an SSH connection with another device
SSH server: Software installed on a machine that allows for that device to accept an SSH connection
Standardization: A systematic way of naming hosts
Swap space: The allocated space where the virtual memory is stored on the hard drive when the amount of physical memory space is used up or full
System: A group of hardware components and software components that work together to fun the programs or processes in the computer
System settings: Settings like display resolution, user accounts, network, devices, etc.
Task bar: It gives us quick options and shows us information like network connectivity, the date, system notifications, sound etc
Terminal: A text based interface to the computer
Time slice: A very short interval of time that gets allocated to a process for CPU execution
Ubuntu: The most popular Linux consumer distribution
User name: A unique identifier for a user account
User space: The aspect of an operating system that humans interact with directly like programs, such as text editors, music players, system settings, user interfaces, etc.
Virtual Box: An application you can use to install Linux and have it completely isolated from your machine
Virtual machine (VM): An application that uses physical resources like memory, CPU and storage, but they offer the added benefit of running multiple operating systems at once
Virtual memory: A combination of hard drive space and RAM that acts like memory which our processes can use
VPN (Virtual private network): A secure method of connecting a device to a private network over the internet
Mobile Display Types
In this reading, you will learn about several types of displays used in modern mobile devices and monitors. As an IT Support professional, you may need to troubleshoot various types of displays. This might involve repairing damaged mobile device screens. You may even be responsible for selecting and ordering mobile devices for the employees of an organization. In your IT job role, you should have a basic understanding of the technology behind modern displays, as well as their common uses, positive features, and negative flaws. The top two technologies used in mobile system displays are Liquid Crystal Displays (LCD) and Light Emitting Diodes (LED).
Liquid Crystal Display (LCD)
LCDs use liquid crystal technology. Liquid crystals have the properties of both a liquid and a solid. The crystals can be aligned in a variety of patterns and manipulated with electricity. How the liquid crystals are arranged and manipulated inside display panels affects refresh rates, image quality, and display performance. LCDs require backlighting, often provided by LEDs. Displays that need backlighting are also called non-emissive or passive displays. The backlighting unit (BLU) requires extra space, which makes LCD panels thicker and less flexible than other displays. Polarizers on either side of the liquid crystal layer control the path of the backlight to ensure the light is aimed toward the user.
The following are common LCD display types used for mobile devices:
In-Plane Switching (IPS)
- How it works: In IPS displays, the liquid crystals are aligned horizontally to the screen. Electricity is passed between the ends of the crystals to control their behavior.
- Uses: IPS technology is used in touch screen displays and high-end monitors. They are often used for design, photography, video/film editing, animation, movies, and other media. They can also be used for games that rely on color accuracy and wide viewing angles, as opposed to speed.
- Positives: IPS displays provide vibrant colors, high quality graphics, and wide viewing areas. Additionally, they offer excellent color reproduction, accuracy, and contrast.
- Negatives: IPS displays are expensive. They have low refresh rates and slow response times. However, response times have been improving as the IPS technology evolves. IPS displays can be affected by “IPS Glow”, where the backlight is visible from side viewing angles.
Twisted Nematic (TN)
Twisted Nematic (TN) is the earliest LCD technology that is still in use today. The term nematic, which means “threadlike,” is used to describe the appearance of the molecules inside the liquid.
- How it works: In TN displays, the liquid crystals are twisted. When voltage is applied, the crystals will untwist to change the angle of the light they transmit.
- Uses: TN displays are appropriate for basic business use (e.g., email, document, and spreadsheet applications). They are also used for games that need rapid display response times.
- Positives: TN displays are low cost, easy to produce, have excellent refresh rates, response times, and resolutions. They are versatile and can be manufactured for any size and/or shape.
- Negatives: TN displays have narrow viewing angles, low image quality, color distortion, and poor color accuracy and contrast.
VA-Vertical Alignment
- How it works: In VA displays, the liquid crystal molecules are vertically aligned. They tilt when electricity passes through them.
- Uses: VA displays are intended for general purpose. Provides mid-range performance for graphic work, movies, and TV.
- Positives: VA displays offergreat contrast, deep black shades, and fast response times. They are mid-range quality for refresh rates, image quality, viewing angle, and color reproduction.
- Negatives: On VA displays, motion blur and ghosting occurs with fast-motion visuals.
Organic Light Emitting Diodes (OLED)
OLEDs are diodes that emit light using organic (carbon-based) materials when electricity is passed through the diodes. Displays that are able to convert electricity into light are called emissive or active displays.
- How it works: The basic structure of an OLED display consists of an emissive layer placed between a cathode (which injects electrons) and an anode (which removes electrons). Electricity enters through the cathode layer, passes into the emissive layer and conductive layer to create light, then out through the anode layer.
- Uses: OLED display technology can be used in foldable smartphones, rollable TVs, as backlighting in LCD TVs, for gaming, and inside VR headsets.
- Positives: OLED displays deliver excellent picture quality, wide viewing angles, infinite contrast, fast response rate, and brilliant colors with true blacks. They are energy efficient, simpler to make, and much thinner than LCDs. OLED panels can be built to be flexible and even rollable.
- Negatives: OLED displays are sensitive to light and moisture. Blue LEDs degrade faster than other LED colors causing color distortion over time. They are also prone to image retention and burn-in.
Active Matrix Organic Light Emitting Diode (AMOLED)
Active Matrix Organic Light Emitting Diode (AMOLED) and Super AMOLED are recent technologies used in smartphone displays.
- How it works: AMOLED displays are a type of OLED panel that uses active matrix technology. Active-matrix displays have active capacitors arranged in a matrix with thin film transistors (TFTs). This technology enables the control of each individual pixel for rapid state changes, including changing brightness and color. AMOLEDs have touchscreen functions integrated into the screen.
- Uses: AMOLED and Super AMOLED panels are used in high-end mobile devices, flat screen monitors, curved screens, and touchscreens.
- Positives: AMOLED displays offer a high picture quality and fast response time. Color and brightness are consistent across the screen. Fast-moving images and motion are displayed clearly without blurring or ghosting. Super AMOLED panels can display a wider range of colors with enhanced contrast, which makes them easy to view in a wider variety of lighting conditions.
- Negatives: AMOLED displays have the same problems as OLED displays (listed above) plus AMOLED panels can be difficult and expensive to manufacture.
Inorganic mini-LEDs (mLEDs)
Inorganic mini-LEDs (mLEDs) are a next-generation, emissive display technology.
- How it works: Mini-LED displays work the same way that OLED displays work, but the individual LED size is much smaller at approximately 50-60 micrometers.
- Uses: Mini-LED displays are used for LCD backlighting in smartphones, public information displays, signage, electronics, vehicle displays, and more. Mini-LEDs are also the tech behind “Liquid Retina XDR” screens.
- Positives: Mini-LED displays offer ultra high luminance, superior HDR fineness, long lifetimes, thin panels, and are readable in sunlight. They are also less expensive than micro-LED displays.
- Negatives: Mini-LED displays, when used as LCD backlighting, are limited by the properties of LCD technology. Mini-LED displays for mobile devices are more expensive than OLED displays.
Inorganic micro-LEDs (μLEDs)
Micro-LEDs (μLEDs) are also emissive, next-generation displays.
- How it works: Micro-LED displays work the same way that OLED displays work, but the individual LED size is extremely small at 15 micrometers.
- Uses: Micro-LED displays can be used in smartphones, AR/VR headsets, wearables, public information displays, wall-sized TVs, vehicle displays, and more.
- Positives: Micro-LED displaysoffer superior performances across virtually all common display features, such as brightness, reaction speeds, power consumption, durability, color gamut, stability, viewing angles, HDR, contrast, refresh rates, transparency, seamless connectivity, and more. Micro-LED displays are readable in sunlight and have sensor integration capability.
- Negatives: Micro-LED displaysare expensive to manufacture and are not yet ready for mass production.
Key takeaways
The two main technologies used in mobile displays are Liquid Crystal Display (LCD) and Organic Light Emitting Diodes (OLED). Each technology has its own benefits and drawbacks when used in mobile device displays, among other consumer goods.
- Common LCDs include:
- In-Plane Switching (IPS) displays
- Twisted Nematic (TN) displays
- VA-Vertical Alignment displays
- Common and upcoming OLED displays include:
- Active Matrix Organic Light Emitting Diode (AMOLED) displays
- Inorganic mini-LEDs (mLEDs) displays
- Inorganic micro-LEDs (μLEDs) displays
Power Supplies
In this reading, you will learn how to select the correct power supply for a personal computer (PC) to support the main components of the PC.
As you learned in a previous video, computer systems require a direct current (DC) of electricity to operate. However, power companies deliver electricity in alternating currents (AC). AC power can damage the internal components of a computer. To solve this problem, computer power supplies are used to convert the AC from the wall socket to DC. Power supplies also reduce the voltage delivered to the computer’s internal components.
Computer architecture
Computer architecture refers to the engineering design of computers and the interconnecting hardware components that together create computing devices that meet functional, performance and cost goals. Power supplies are part of the hardware layer of a computer’s architecture. You learned earlier about the other major hardware components of a computer’s architecture, including the motherboard, chipsets, CPUs, RAM, storage, peripherals, expansion slots and cards, etc. These components influence the size and type of power supply a computer needs.
Selecting a power supply
Local input voltage
A main consideration when selecting a computer power supply is the voltage delivered to common wall sockets in your country. Power standards for input voltages can vary from country to country. The most common voltage inputs are 110-120 VAC and 220-240 VAC. VAC stands for volts of alternating current.
- Voltages in the Americas
North, Central, and parts of South America use the 110-127 VAC standard for common wall sockets. Computers and power supplies sold in these regions are designed to use this level of power.
- Voltages for most of the world
Most countries use the 220-240 VAC standard for common wall sockets. Computers and power supplies sold in these areas are designed to use this higher voltage.
Please visit WorldStandards “Plug, socket & voltage by country” to find your country’s voltage standards.
It is important to use the correct voltage power supply or power converter for the computer’s voltage specifications. Imagine that you have a customer who imported a PC from a country that uses a different standard for input voltage. You will need to adapt the input power to protect the computer. Some options for doing this might include:
- Replace the power supply with a unit that uses the appropriate voltage for the target country.
- Install a power supply model that includes a dual-voltage switch that can be toggled from 110-120VAC to 220-240VAC.
- Plug the computer into an external power converter that then plugs into a normal wall socket. Power converters can be purchased from any store that sells international travel merchandise.
Without a power converter, the following problems may be experienced:
| If a computer needs | But the wall socket delivers | The result will be |
|---|---|---|
| 220-240VAC | 110-120VAC | not enough power for the computer to run properly |
| 110-120VAC | 220-240VAC | too much power, which will damage the computer’s internal parts |
Motherboard engineering specifications
The motherboard and form factor specifications document will provide a list of compatible power supply types to help you select the correct part. The ATX form factor is the most common motherboard design for full-sized, personal desktop computers. You may also find a version of the ITX form factor in smaller computers. The form factor size and components embedded in the motherboards will create a starting point for the minimum power supply wattages required.
Power consumption of components
The number of internal components and peripherals the computer will need to support will also determine the minimum wattage a power supply must provide. For example, a basic computer that is designed for word processing and surfing the Internet should work with a standard power supply. However, some computers may need higher wattage power supplies to support items like a powerful CPU, multiple CPUs, multiple hard drives, video rendering applications, a top-tier graphics processing unit (GPU) for gaming, and more.
Voltages and pin connectors
The internal hardware components of a computer require varied input voltages to operate. Voltage regulators embedded in the motherboard of the computer control the amount of power that is delivered to the computer’s various internal components.
| Voltage | Examples of components that use each voltage level |
|---|---|
| 3.3V | DIMMs, chipsets, and some PCI/AGP cards |
| 5V | SIMMS, disk drive logic, ISA, and some voltage regulators |
| 12V | Motors and voltage regulators with high outputs |
The computer’s power supply plugs into an adapter on the computer’s motherboard. The wiring for this connection uses color coded wires. Each wire color carries a different voltage of electricity to the motherboard or serves as a grounding wire. A standard ATX motherboard power adaptor has either 20-pins or 24-pins to connect these wires. The 20-pin design is an older technology. The 24-pin connector was developed to provide more power to support additional expansion cards, powerful CPUs, and more. The 24-pin connector has become the standard for today’s personal computer power supplies and motherboards.
The power supply will have multiple connectors that plug into the motherboard, hard drives, and graphic cards. Each cable has a specific purpose and delivers the appropriate amount of electricity to the following parts:
Connections from a PC power supply (ATX 2)
- Floppy disk drive (obsolete)
- “Molex” universal (e.g. IDE hard drives, optical drives)
- SATA drives
- Graphics cards 8-pin, separable for 6-pin
- Graphics cards 6-pin
- Motherboard 8-pin
- Motherboard P4 connector, can be combined to 8-pin mainboard connector 12V
- ATX2 24-pin, divisible 20+4, and can therefore also be used for old 20-pin connections
You will learn how to install a power supply and connect these power cables later in this module.
Key takeaways
When selecting a power supply for a computer, the following items should be taken into consideration:
- Wall socket input voltage standard for the country where the computer will be used;
- The number and power consumption needs of the computer’s internal components;
- The motherboard model and form factor engineering specifications and requirements.
Resources for more information
For more information on these topics, please visit:
- Plug, socket & voltage by country – List of countries around the world and their voltage standards for common wall sockets and plug types.
- How to Diagnose and Replace a Failed PC Power Supply – Step-by-step illustrated instructions on how to diagnose a power supply failure and replace it on a desktop PC.
