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C393 - IT Foundations (A+ Core 1)

Exam Compass -> Professor Messer -> Dion Practice -> Win.

Last updated: May 4th, 2023

Course Notes

Module 1: Mobile Devices

Laptop Displays

Portable LCD

Advantages

Lightweight
Low power consumption
Relatively Inexpensive

Disadvantages

Black level challenges
Requires backlight
Lights are difficult to replace

Backlight Tech

CCFL

Cold Cathode Fluorescent Lamp
Uses mercury
Not as efficient as LEDs

TN

Twisted Nematic
Fast response time
Low viewing angle

IPS

In-Plane Switching
Excellent Color
More Expensive than TN

VA

Vertical Alignment
Compromise between TN and IPS
Slow response time

OLED

Organic Light Emitting Diode
Uses organic compounds that emit light when electric current is recieved.
Thin and lightweight
High contrast
No backlight allows true black

Inverter

Turn DC into AC

Digitizer

Converts touch input into digital data

Cellular Standards

PRL

Preferred Roaming List
Contains a list of towers that the phone will connect to

2G

GSM

Global System for Mobile Communications
90% of the global market
EU Standard
Used by AT&T and T-Mobile
Multplexing

CDMA

Code Division Multiple Access
Used by Verizon and Sprint
Calls use unique codes

3G

Introduced in 1998
Better connectivity enabled new functionality
Several megabits per second
HSPA
EVDO

4G

LTE

Long Term Evolution
Introduced in 2009
Based on GSM and EDGE
Supports 150 Mbps

LTE Advanced

Supports 300 Mbps

5G

Introduced in 2019
Supports 10 Gbps
IoT impact

Module 2: Networking

Common Ports and Services

FTP

tcp/20 for data
tcp/21 for control

SSH

tcp/22

Telnet

tcp/23

SMTP

tcp/25
Server to Server

DNS

udp/53

DHCP

udp/67
udp/68

HTTP

tcp/80

POP3

tcp/110
Server to one client

IMAP

tcp/143
Server to multiple clients

HTTPS

tcp/443

SMB

tcp/445
NetBIOS

tcp/137 for name services, registration, removal by name
tcp/139 for session services and data transfer

SNMP

udp/161 for queries/metrics/management
udp/162 for responses/traps/alerts
V1

Structured Table
Cleartext

V2

Enhanced data types
Bulk Transfer
Cleartext

V3

Authentication
Encryption

LDAP

tcp/389

RDP

tcp/3389

Network Devices

Routers

Connects networks
Forward packets based on IP
Layer 3

Switches

Forward packets based on Layer 2 address
Multilayer switch includes router functionality
Unmanaged Switches

Plug and play
Fixed Configuration
Cheap

Managed Switches

Supports VLANs
Traffic Prioritization
SPT redundancy
Port mirroring
SNMP

Hub

Connects devices
Repeats all traffic to all ports

Patch Panels

Connects cables to switches
Keeps cables organized

Power over Ethernet

POE

IEEE 802.3af - 2003
15.4W DC, 350mA max current

POE+

IEEE 802.3at - 2009
25.5W DC, 600mA max current

POE++

IEEE 802.3bt - 2018
51W (Type 3), 600mA max current
71.3W (Type 4), 960mA max current
PoE with 10GBASE-T

ONT

Optical Network Terminal

Network Tools

Cable Crimper

Strips, cuts, and crimps cables

WiFi Analyzer

Identifies errors and interference

Tone Generator

Identifies cable runs using analog sound

Punchdown Tool

Punches down wires into patch panels

Cable Tester

Tests for continuity

Loopback Plug

Useful for testing physical ports

Taps and Port Mirrors

Used to monitor and intercept traffic

Software Defined Networking

Split the network into 3 layers

Control Plane
Data Plane
Management Plane

Control Plane

Routing tables
Session tables
NAT tables

Data Plane

Process network frames and packets
Forward packets

Management Plane

Configuration
Monitoring

Wireless Network Standards

802.11a

1999
5GHz
54Mbps

802.11b

1999
2.4GHz
11Mbps

802.11g

2003
2.4GHz
54Mbps

802.11n (WiFi 4)

2009
2.4GHz and 5GHz
40MHz channel widths
150Mbps per MIMO stream
600Mbps

802.11ac (WiFi 5)

2013
5GHz
160MHz channel widths
867Mbps per MIMO stream
6.9Gbps
Eight EU-MIMO downlink streams

802.11ax (WiFi 6)

2021
2.4GHz and 5GHz
20, 40, 80, 160MHz channel widths
1.2Gbps per MIMO stream
9.6Gbps
Eight bidirectional Multi-User MIMO (MU-MIMO) streams
Orthogonal Frequency Division Multiple Access (OFDMA)

WiFi Channels

2.4GHz

1-11, in the US and Can
1-13, in the EU
1-14, in Japan
1, 6, 11 are the most common
b, g, n, and ax

5GHz

Not as effective at penetrating walls
a, n, ac, and ax

Assigning IP Addresses

DHCP

Replaced BOOTP in 1997

BOOTP was Introduced in 1993

APIPA

Automatic Private IP Addressing
IPs are assigned when DHCP is not available
169.254.0.0/16

DNS

Address Records

A

IPv4

AAAA

IPv6

MX Records

Mail Exchanger

SPF

Sender Policy Framework
Prevents spoofing

DKIM

Domain Keys Identified Mail
Digitally sign outgoing mail

DMARC

Domain-based Message Authentication, Reporting, and Conformance
Combines SPF and DKIM

Internet Connection Types

DSL

Direct Subscriber Line
Uses existing copper telephone lines
CO (Central Office) - CPE (Customer Premises Equipment)
200Mbps/DOWN, 20Mbps/UP

Cable

Broadband
50Mbps to 1Gbps
Uses insulated and shielded coaxial cable
DOCSIS

Data Over Cable Service Interface Specification

Fiber

Higher cost than copper
Uses glass or plastic surrounded by a protective coating to transmit light.
SONET

Synchronous Optical Network

Satellite

Uses a satellite dish to receive signals from a satellite in orbit
High cost
Good for remote locations

Cellular

Uses radio waves sent from a cell towers that are placed in a way to divide the land into cells

WISP

Wireless Internet Service Provider
Need an antenna

Module 3: Hardware

Network Cables

Twisted Pair

Cat 5

1000Base-T
100 meters

Cat 5e

1000Base-T
100 meters
Enhanced

Cat 6

10GBASE-T
Unshielded: 55 meters
Shielded: 100 meters

Cat 6a

10GBASE-T
100 meters
Augmented

S

Braided Shielding

F

Foil Shielding

U

Unshielded

Coaxial

RG-6 used in TV cable

Plenum-rated Cable

Fire resistant
Flourinated Ethylene Polymer (FEP) or Polyvinyl Chloride (PVC)

Optical Fiber

No electrical interference, difficult to monitor or tap
Single-mode

Short-Range; 2km
May use LEDs or other inexpensive light sources

Multimode

Long-Range; 100km
Uses lasers

568A and 568B

568A

White/Green
Green
White/Orange
Blue
White/Blue
Orange
White/Brown
Brown

568B

White/Orange
Orange
White/Green
Blue
White/Blue
Green
White/Brown
Brown

Peripheral Cables

USB

Universal Serial Bus
USB 1.0 - 1.5Mbps
USB 1.1 - 12Mbps
USB 2.0 - 480Mbps
USB 3.0 - 5Gbps
USB 3.1 - 10Gbps
USB 3.2 - 20Gbps
USB 3.2 Gen 2x2 - 40Gbps
USB 4.0 - 40Gbps

DB-9

Serial
Commonly used as a console port

IDE

Integrated Drive Electronics
Parallel
Used for hard drives and optical drives
40-pin

Video Cables

VGA

Video Graphics Array
DE-15
15-pin D-Sub
Blue color
Analog
Degrades after 5 to 10 meters

DVI

Digital Visual Interface
Single Link

3.7 Gbps (HDTV at 60 fps)

Dual Link

7.4Gps (HDTV at 85 fps)

No audio
DVI-A

Analog

DVI-D

Digital

DVI-I

Integrated
Can be analog or digital

HDMI

High-Definition Multimedia Interface
All digital
19-pin
Audio and video
Degrades around 20 meters

DisplayPort

Information is sent in packets
Compatible with HDMI and DVI
Video and Audio

SATA

Serial Advanced Technology Attachment
Revision 1.0 - 1.5 Gbps
Revision 2.0 - 3.0 Gbps
Revision 3.0 - 6.0 Gbps
Revision 3.2 - 16.0 Gbps
Uses a 7-pin connector for data
Uses a 15-pin connector for power
Commonly used for storage devices

SCSI

Small Computer Systems Interface
Some configuration is done by the SCSI

Connectors

RJ-11

Telephone or DSL
6P2C
Used for analog phone lines

RJ-45

8P8C
Commonly used for Ethernet

RS-232

Versatile
DE-9
DB-25
It has the two twist things

BNC

Bayonet Neill-Concelman
Used for coaxial cable
Twist-lock

F-Connector

Coaxial
Associated with Cable

Fiber Connectors

ST

Straight Tip
It has the extended tip

SC

Subscriber Connector
Square

LC

Latching/Local Connector
Often comes in a pair

Memory

DIMM

Dual Inline Memory Module
Used for desktops
SODIMM

Small Outline DIMM
Used for laptops

DDR

Double Data Rate

SDRAM

Synchronous Dynamic Random Access Memory

Parity Bit

In a set of 8 bits, one bit is used to check the other 7 bits
It checks if there is an even or odd number of 1s, if odd the parity bit will equal one. If even, the parity bit will remain zero

ECC

Error Correcting Code
High Integrity

Storage

AHCI vs NVMe

AHCI

Advanced Host Controller Interface
Move data from the hard drive to RAM
Designed for hard drives

NVMe

Non-Volatile Memory Express
Move data from the hard drive to RAM
Uses PCIe
Designed for SSDs

M.2 Interface

B-Key
M-Key

RAID

Redundant Array of Independent Disks
RAID 0

Striping
Fastest
Least reliable, no redundancy
Does not increase capacity

RAID 1

Mirroring
Slowest
High redundancy
Requires two drives

RAID 5

Striping with parity
Fast
Reliable
Requires 3 or more drives

RAID 10

Striping with mirroring
The speed of striping and the reliability of mirroring
Requires 4 or more drives

Motherboards

Form Factor

ATX

Best used in servers or desktops
Standardised in 1995
20pin or 24pin power connector
8pin or 4pin CPU power connector

Micro ATX

Commonly used in small desktops
Same as ATX but smaller
Uses a 20pin power connector

ITX

Low power
Small
Compatible with ATX screws
Useful for single-purpose computers, such as a media center

Expansion Slots

Computer Bus

Sends data between devices

Expansion Bus

Connects the motherboard to the expansion cards
Width of the bus determines the speed of the data transfer
Clock rate is the speed of the bus

PCI

Peripheral Component Interconnect
The PCI bus is a type of expansion bus
The PCI slot provides power to cards
32-bit is shorter in length and has less pins than 64-bit pci card/slot
PCIe

Peripheral Component Interconnect Express
Replacement for PCI, PCI-X and AGP
Communicates serially using serial lanes (serial experiments lain?)
Used for GPUs, RAID controllers, network cards, sound cards, etc
PCIe x1

1 lane
1.5GB/s
Network Cards

PCIe x4

4 lanes
6GB/s

PCIe x8

8 lanes
12GB/s

PCIe x16

16 lanes
24GB/s
Graphics Cards

Riser Card

Allows cards to be placed in different orientations

Connectors

CPU Socket

Not an easy task to replace

ZIF Socket

Zero Insertion Force
Used for CPUs
Has lots of holes for Pin Grid Array (PGA) CPUs

LGA Socket

Land Grid Array
Reverse of PGA

Storage Connectors

SATA
PATA

Uses IDE slot

BIOS

Navigating to BIOS Settings

Del, F1, F2, CTRL-S, CTRL-ALT-S
Hold shift when pressing restart in Windows

UEFI Secure Boot

Verifies the bootloader by checking the signature

TPM

Trusted Platform Module
Crypto processor

HSM

Hardware Security Module
Crypto Hardware, Key Backup, Crypto Accelerator

CMOS

Complementary Metal Oxide Semiconductor
Stores BIOS settings
Uses a battery to keep settings when the computer is off
Modern systems use a flash memory chip instead

CPU technologies

ARM

Advanced RISC Machine
Power efficient

Simpler instruction set

Used in mobile and IoT devices

Multithreading

HTT
One CPU acts like two

Usually sees a performance increase of 15-30%

Most modern OS support this

Virtualization

Intel VT-x
AMD-V

Computer Power

Always disconnect a device when working on it
If a device stores a charge in a capacitor, it will still have power even when disconnected
Power Supply

Converts 120V AC or 240V AC to 3.3V DC, 5V DC, 12V DC

Amp, Watt, Volt, Ohm

Amp = Current

How much charge is flowing through a circuit
The diameter of the hose

Volt = Voltage

Electrical pressure
How open the faucet is

Watt = Power

How much energy is being used
Watt = Volt * Amp

Ohm = Resistance

How much resistance there is to the flow of electricity
Ohm = Volt / Amp

Current

AC

Alternating Current
Current that changes direction
US/Canada use 120V AC, 60Hz
Europe uses 240V AC, 50Hz

DC

Direct Current
Current that flows in one direction

Ground

Electrical current flows to ground
Ground is a conductor
Ground is a reference point

Power Supply Output

+12V

PCIe adapters, hard drives, optical drives, fans

+5V

Some motherboard components

+3.3V

M.2 SSDs, RAM slots, logic circuits

+5VSB

Standby voltage

12V

Integrated LAN
Older serial ports

-5V

ISA slots
Not used anymore

Multifunction Devices

Printers

Laser

Processing in memory
Charge drum
Exposing with laser
Add toner to charged areas
Transfer to paper
Fuse with heat
Remove excess toner

Pros

Fast
High quality

Cons

Complex
Moving Parts

Image Drum

Contains the toner
Drum rotates and applies toner to the paper
Image is drawn on the drum by the laser

Fuser Assembly

Melt plastic toner using heat and pressure

Transfer Belt

Image is transferred from all cartridges to the single belt
Cyan, Magenta, Yellow, Black

Pickup Roller

Rolls the paper through the printer

Separation Pad

Pulls one sheet from the paper tray

Duplexing assembly

Prints on both sides of the paper

Maintenance

Replace toner, low does not mean empty
Toner may contain the OPC drum, sensitive to light
Printers page counter will tell you when to perform maintenance
Clean the printer routinely, the toner and paper dust spreads. Stick to the manufacturers recommendations

Inkjet

Pros

Low cost tech
Quiet
High resolution

Cons

Ink is proprietary and expensive
Ink Fades
Print head clogs

Ink Cartridge

CMYK
Place droplets of ink on the paper

Print Head

Occasionally the print head will be integrated into the ink cartridge
Print head may clog

Feed Roller

Rolls the paper through the printer

Carriage and Belt

Carriage moves the print head back and forth
Belt moves the carriage

Maintenance

Replace ink cartridges when they are empty, empty cartridge can be recycled.
Jams are inevitable
Calibrate the printer routinely

Thermal

Pros

Very Quiet
No ink

Cons

Sensitive to light and heat

Thermal Paper

Paper changes color when heated

Feed Assembly

Rolls the paper through the printer

Heating element

Heats the paper

Maintenance

Thermal paper measurements differ
A cleaning pen and IPA can be used to clean the heating element

Impact

Pros

Low cost per page
Good for multiple copies

Cons

Low resolution
Noisy

Print Head

Moves back and forth, pressing a ribbon against the paper

Ribbon

One ribbon
Proprietary size

Maintenance

Replace ribbon when ink lightens
Print head can be replaced when the ribbon is replaced

3D

Filament

FDM

Fused Deposition Modeling
More Common than SLA
Uses a heated nozzle to melt plastic

SLA

Stereolithography
Uses a laser to cure a liquid resin
Resin is hazardous

Module 4: Virtualization and Cloud Computing

Cloud Deployment Models

Public Cloud

Resources are shared with the public

Private Cloud

Resources are shared with a single organization

Hybrid Cloud

A mix of public and private cloud

Cloud Service Models

Software as a Service (SaaS)

Software is hosted by the cloud provider
Users access the software through a web browser
Examples: Google Docs, Office 365

Platform as a Service (PaaS)

Platform is hosted by the cloud provider
Users can develop and deploy their own applications
Examples: Google App Engine

Infrastructure as a Service (IaaS)

Infrastructure is hosted by the cloud provider
Users can deploy their own applications
Examples: Amazon Web Services

Virtualization

Hypervisor

Software that creates and runs virtual machines
Type 1: Runs directly on the hardware

Examples: VMware ESXi, Microsoft Hyper-V

Type 2: Runs on top of an operating system

Examples: VMware Workstation, VirtualBox

Requirements

AMD-V or Intel VT-x

Security Concerns

VM escape

VM escapes the hypervisor and gains access to the host
Often is done using shared memory, clipboard, drives, etc

VM sprawl

VMs become unmanageable

Module 5: Hardware and Network Troubleshooting

Troubleshooting

Identify the problem
Establish a theory of probable cause
Test the theory
Create a plan to fix the problem
Implement the plan
Verify the problem is fixed
Document the solution

Hardware Troubleshooting

POST

Power On Self Test
Test major components before boot
Beep codes

POST and Boot

Blank screen on boot

Any beeps?
Bad video, bad RAM, bad cpu, bios misconfiguration

BIOS time and settings

Maintained with the motherboard battery

Boots in incorrect order

Check boot order in BIOS
Does the selected device have a valid OS?
Is the device connected?

Crash Screen

Blue Screen of Death (BSOD)

Windows
Driver issue
Use last known good configuration
Use safe mode

Spinning ball of death (SBOD)

Mac
App bug, bad hardware, disk issue
Restart
Check logs

Black Screen

Is the monitor plugged in and turned on?
Is the monitor using the correct input?
Try another monitor
If no video after windows loads, try vga mode (f8)

No power

Use a multimeter to check for power
Is anything powered on? Fans?

Check PSU output
On a laptop, check the power brick
On a desktop, check the power switch
If the laptop is plugged in and working but shuts off when unplugged, the battery is bad or not plugged into board

Sluggish performance

Task manager, update, disk space, powersaving, virus

Overheating

Check fans, vents, heat sink, bad components
Use a can of compressed air to clean out dust
cpuid.com

Intermittent Shutdown
- Heat, Hardware
- Eliminate working parts
App crashes

Look for error message, check event logs, check the reliabiltiy monitor

Grinding noises

Bad hard drive, bad fan, blown capacitor, bad power supply

Lockups

Check for responses, try shortcuts, update drivers and software, low resources

Continuous Reboot

F8

Storage Troubleshooting

Symptoms

R/W errors
Slow performance
Clicking/Grinding noises

Disk Failures

Backups, Check for loose/damaged cables
Check for overheating, power supply, run hardware diagnostics

RAID Failures

RAID not found

Faulty controller

RAID stops working

Check the console, every RAID is different

RAID failure conditions

RAID 0: 1 drive failure
RAID 1: 1 must remain operational
RAID 5: All drives must remain operational but one
RAID 10: All but one from each set of mirrors

Video Troubleshooting

Native Resolution

Check the monitor manual

Burn-in

Static images on the screen
Use a white page for a while

Dead Pixels

Pixel is always black
Factory defect

Flashing Screen

Replace cable
Check display settings

Projector Problems

Check the lamp

Relatively expensive to replace
May be hot

Check the filter
Check the fan

Mobile Troubleshooting

Battery

Check battery usage
Aging batteries need to be replaced
Swollen battery

Buildup of gas
Fire risk
Dispose and replace

Liquid Damage

LCI

Liquid Contact Indicator

Power phone down, remove case
Place in silica gel
Leave it alone for at least a day
Power on

Digitizer

Touch screen not working
Check for cracks
Reboot

Networking Troubleshooting

Is there a link light?
Ping loopback
Ping gateway
Ping local device
Ping 8.8.8.8
Tracert

Resources