Midterm Review

Power and Electricity

• ATX is a form factor.
• 3.3V and 5V power the digital circuits.
• ATX12V is the most common power supply.
• 12V powers fans and spinning disk drives.
• Molex is a type of connector.
• ESD is the result of differently charged surfaces coming into contact.
• AC is electrical power from the wall outlet.
• DC is the electrical current the device needs.
• PSU transforms AC power into DC power.
• The form factor describes the physical design and look of a computer case.

Motherboards and Expansion

• ATX's dimensions are 12x9.6.
• RAM is volatile data storage close to the CPU.
• The northbridge controls high-speed comms between the CPU, RAM, and video.
• The motherboard is the backbone of the computer.
• BIOS/UEFI provides the initial power-on test of all electrical components.
• The CPU interprets and executes commands.
• Expansion slots allow the addition of hardware to increase PC capabilities.
• The southbridge controls low-speed comms between CPU and peripheral components.
• ITX is a motherboard form factor.

Storage and Memory

• SSD stores data as a set of electrical charges in flash memory.
• PCIe is the Peripheral Component Interface Express.
• SODIMM is the RAM type used primarily in laptops and notebooks
• Parity can check for single-bit errors but can not correct the errors.
• Cache is very fast, expensive memory very close to the CPU.
• Optical storage saves data as a series of pits in plastic media.
• ECC can check and correct single-bit errors, but can only detect multi-bit errors.
• Magnetic storage saves data as a series of magnetic charges on a metallic spinning disk.

Input / Output

• NVMe is a communication protocol for the 4-lane PCIe.
• HDMI is a video connector that also transmits sound.
• A bit is the smallest unit of data storage or a binary digit.
• VGA is the oldest video connector.
• A byte is eight binary digits treated as a single unit.
• DVI is a newer video connector that does not incorporate sound.
• PS/2 is an older keyboard port that did not support hot-swapping.
• USB is a newer universal device port which supports hot-swapping and daisy-chaining.

More I/O

• 3-D printers melt and deposit filaments to create a printed object on a flat bed.
• A KVM allows control of multiple computers with a single keyboard and mouse.
• Laser printers use light to charge a drum to fuse a page image with heat.
• Inkjet printers are line printers using charged ink droplets to print pages.
• NFC is a wireless communication protocol allowing tap payments through cell phones.
• Impact printers are line printers, which use a printing ribbon to print a page.
• Bluetooth is as a wireless radio protocol used to create a personal area network (PAN).
• Thermal printers are label printers, which use heat to imprint the image.

Cooling, Form Factors, and Power

• An SSHD is a hard drive that combines flash memory with spinning disks.
• Water cooling is a quieter method of cooling the CPU and GPU.
• Hot swapping is the ability for a device to be changed without turning off the power.
• CO2 or Class C are the best fire extinguishers for electrical fires.
• The LGA socket is used with Intel CPUs and Intel-compatible motherboards.
• 3.5"is a common size for hard drives.
• PGA socket is used with AMD CPUs and AMD-compatible motherboards.
• 5.25" is a common size for optical drives.

Starting the Computer

• UEFI is the POST motherboard chip for 32 and 64-bit systems with secure boot.
• POST is the program, which checks all the hardware connected to a PC.
• A battery ensures the correct computer date and setting.
• BIOS is the deprecated motherboard chip where the POST program used to be stored.
• OS loads only after POST completes.
• CMOS is the material, which makes the motherboard chip with the POST program.
• Secure boot prevents rootkit malware from infecting your system.
• Beep codes indicate different hardware problems during POST.

Power Protection

• Blackouts are a complete loss of AC power.
• UPS provides consistent power during brownouts and blackouts.
• TMP is a motherboard chip, which stores passwords, digital certifications, keys, etc.
• A spike is a short, sudden increase in voltage of more than 100%.
• Flashing updates the BIOS or UEFI firmware.
• A surge is a short, but dramatic increase in voltage of less than 100%.
• A brownout is a short period of reduced voltage.
• SPS provides power but takes time to switch over

Redundant Storage and Overclocking

• Throttling happens when a CPU overheats.
• RAID 0 is striping across multiple drives treated as one drive.
• Overclocking can lead to CPU overheating.
• RAID 1 is mirroring one drive to another, with a 2-drive minimum.
• RAID 1+0 has two arrays of mirrored drives (4 total) which are striped, up to 2 can fail.
• RAID 5 strips data with a parity bit that provides data redundancy, 3 drive minimum.
• RAID 6 strips data with double parity, a 4 drive minimum, any 2 can fail without loss.
• Virtualization must be turned on in UEFI in order to run VMs.

Serial vs Parallel and More I/O

• Serial sends bits one at a time.
• VGA is a deprecated video standard using a 15-pin D-shell connector.
• PS/2 is a legacy keyboard/mouse connector that is NOT hot-swappable.
• DVI is a deprecated replacement for VGA.
• Parallel ports send bits simultaneously in groups of eight.
• HDMI supports both video and sound .
• DisplayPort is open-source version of HDMI to replace VGA and DVI.
• USB is a hot-swappable connection port that can daisy-chain up to 127 devices.

Cables

• EMI is interference caused by electrical or magnetic fields.
• SATA is a serial cable for data transfer with modern hard disks.
• UTP is a twisted pair cable, most commonly used for network connections.
• RJ-11 is a connector type for 4-wire copper telephone cable.
• eSATA is a keyed serial data connector for external hard drives.
• STP is a twisted-pair cable shielded to mitigate EMI.
• RJ-45 is a connector type for 8-wire copper twisted pair network cable.
• Coax is a RG-6 or RG-59 copper cable using a BNC or F-connector.

Thermal Compounds and High End Devices

• Pea-sized is the amount of thermal compound to place on the CPU before screwing down the CPU fan.
• The first step when repairing a computer is to backup data.
• SCSI and iSCSI function as a hard drive controller protocols used in high-end storage applications.
• Refresh rate is how quickly a pixel changes color.
• A pixel is a picture element or a small dot capable of RGB display.
• SAN is a high-end storage network
• Contrast ratio is how white or black a screen can get.
• NAS is an inexpensive single-purpose device for adding storage to a network.

Troubleshooting Steps

• Step 3 is to test the theory.
• Step 6 is to document findings and outcomes.
• Step 1 is to ID the problem.
• Step 5 is to verify full system functionality.
• Step 2 is to establish a theory of a probable cause.
• Gathering customer and computer information is step 1.
• Step 4 is to establish a plan of action to resolve the problem.
• Step 6 is to have the customer verify the problem is solved.

RJ45 Standards

• 568B has an Orange wire on pin 2. The 568A standard has a Green wire on pin 2

Common Network Ports

• SSH and SFTP use port 22.
• SCP uses port 22 as well.
• DNS uses port 53.
• SMTP uses port 25.
• FTP uses ports 20 and 21.
• TFTP uses port 69.
• Telnet uses port 23.
• DHCP uses ports 67 and 68.
• HTTP uses port 80.
• HTTPS uses port 443.
• SNMP uses port 161
• RDP uses port 3389.
• NTP uses port 123.
• SIP uses ports 5060 and 5061.
• SMB uses port 445.
• POP uses port 110
• IMAP uses port 143.
• LDAP uses port 389.
• LDAPS uses port 636.
• H.323 uses port 1720.

Network Types

• VLANs segment groups of ports on a switch.
• LAN is created on layer 2 using a switch.
• MAN is a network which spans a city.
• PAN is generally used with Bluetooth devices.
• WLAN uses a wireless access point (WAP) to create a wireless LAN.
• WAN operates on layer 3 using a router to link geographically remote LANs.
• 568B has pin 2 as solid orange.
• VPN is a secure method used to connect two points on an unsecured network.

Transmission Technologies

• POTS or PSTN is telephone network.
• Latency measures round-trip time for data to travel between two devices.
• ISDN is a circuit-switched telephone system carrying both data and voice on a digital line.
• Cable shares the network with multiple subscribers.
• Tethering connects a device to a cell phone to obtain internet connectivity.
• DSL requires filters to carry data and voice along the phone line.
• A hotspot is a cell phone that provides internet connectivity for another device.
• Satellite is the technology with the worst latency.

Protocols

• 20, 21 is the port for unsecure file transfers.
• 443 is for secure web browsing.
• TCP is connection-oriented data transfer.
• 389 resolves resources (users, printers, etc) on a network.
• 3389 is Windows remote desktop protocol.
• Port 110 is for the client email download (no synch).
• Port 69 is unsecure router and switch config file transfer.
• UDP is connection-less data transfer.

Wireless

• 802.11g has a speed of 54 Mbps at 2.4 GHz.
• 802.11ac has a speed of 1.3 Gbps at 5 GHz using MU-MIMO.
• 802.11a has speed of 54 Mbps at 5 GHz.
• 802.11n has a speed of 600 Mbps at 2.4 and 5 GHz with MIMO
• RFID are used to track devices.
• 802.11b has a speed of 11 Mbps at 2.4 GHz.
• 802.11ax has a speed of 3.5 Gbps at 5 GHz.
• NFC is used for tap payments.

Frequency Channel Interference

• 802.11 Wireless Standards of 2.4 frequency channels do not interfere with each other on channels: 1,6,11

Cell Phone Communication

• 4G cell communication has speeds of 670 Mbps, LTE and IPv6 protocols.
• 2G cellular communication has speeds of 200 Kbs.
• FQDN is a complete URL designation.
• 3G cell standards support 2 Mbps (video streaming).
• DNS translates FQDNs into an IP address.
• 5G wireless standards supports AR and DR at 3 Gbps.
• DHCP auto-provides an IP address, netmask and default gateway.
• SFTP and SCP securely copy files from one Linux device to another.

More Networking Devices

• Proxy servers hide clients behind them and cache frequently accessed data.
• Repeaters are layer 1 devices that regenerate signals to send further.
• RADIUS is an open-source AAA server.
• AAA authenticates and authorizes remote users to access network devices.
• A syslog server stores log files for network devices.
• TACACS+ is Cisco-proprietary.
• Switches are layer 2 devices that divides a network into segments and perform error checks.
• Bridges are layer 2 devices that divides networks into segments, but does not have error-checking.

Security Devices

• Firewalls use ACLs to protect devices.
• IPSs detect and try to prevent intrusions while notifying the admin.
• WAPs provide access for wireless devices.
• ACLs are rules used to determine what data access to permit.
• Routers, which are layer 3 devices, connects remote LANs together.
• An IDS detects intrusions and notifies admins, but does not try to stop them.
• EMSs monitor endpoint devices like PCs, tablets, laptops, and cell phones.
• A UTM is a single network device that performs multiple security functions.

Networking Tools

• PoE uses an ethernet cable to supply both data and power to a device
• Crimpers securely attach an RJ-45 jack to an Ethernet cable.
• Legacy is a system that is past end of life but is stilled used due to critical need.
• A punch-down tool is used to secure cables into a 66 or 110 block.
• Patch panels are centralized location for connecting network cables.
• EoP uses existing live electrical AC wall wires to transmit data.
• Multimeters measure electrical chremical characteristics of electronic device.
• Wire strippers are used to remove plastic cladding from ethernet cable wires.

Network Testing

• Coax cabling is RG-6 or RG-59 cable that uses either BNC or F-connector terminations.
• Tone generators find the correct cable in a mass of cables.
• Wifi analyzers are used during a site survey in preparation for installing WAPs.
• Cat 5e is a 1 GBps cable with a max distance of 100 m (after which a repeater is needed).
• Loopback adapters are testing dongle that is used to check a hardware port on a NIC.
• UTP- 8-wire copper cable that is not immune to EMI.
• A cable tester checks the electrical correctness of an ethernet cable.
• STP - 8-wire copper cable that is protected against EMI.

Cabling Specifics

• Fiber cables use light to transmit data, is not affected by EMI or RFI.
• 568A has wire 2 as solid green
• MMF uses several wavelengths of light and can transmit several hundred meters.
• ST is a fiber connector with a twist-lock.
• 568B has wire 2 as solid orange.
• SMF uses a single wavelength of light and transmits over several kilometers.
• SC is a Fiber connector that is square.
• LC is a Fiber connector that is always duplex.

PC Addressing

• Network name is the first part of an IPv4 address.
• A MAC address is a 48-bit hexadecimal physical address, 12-digits separated by anything.
• Host name is the second part of an IPv4 address.
• IPv4 is a 32-bit decimal logical address with 4 numbers separated by dots.
• Subnet mask is a number string which indicates where a network name ends.
• IPv6 is 128-bit hexadecimal logical addresses, 32-digits separated by colons.
• Ipconfig /all shows the MAC, IPv4 and IPv6 addresses.
• Double colon shows where multiple zero digit groups are in an IPv6 address.

Network Settings

• DHCP Server provides auto-IP addressing to network devices.
• Link local is the IPv4 address of APIPA.
• Static is an address entered by a network administrator.
• The IP in APIPA address is 169.254.x.y.
• Default gateway is the address used to transmit to another network.
• FE80:: is the first group in an IPv6 link-local address.
• DNS Server converts host names into IP addresses.
• Network name is the first part of an IPv4 address.

Common Lan Settings

• Ipconfig /release clears the existing IP Address.
• Ping is the CLI that uses ICMP to test network connectivity at layer 3.
• Ipconfig /renew asks the DHCP server for a new IP address.
• Device manager holds device configuration information.
• QOS prioritizes streaming audio and video.
• The first thing that needed when setting up a new router is changing the password.
• NAT converts the public IP address into private IP Addresses.
• DMZ is a limited public-access area on a network.

Adapters Specific to Ports

• A docking station uses proprietary laptop connectors to allow the connection of additional devices.
• GPS allows the use of geofencing.
• LCD has TN or IPS and sometimes has flourescent backlighting.
• Function keys provide extra capabiltities to laptop keyboards.
• SO-DIMM is the kind of RAM used in laptops.
• Inverters power the fluorescent backlight on a laptop.
• The port replicator uses USB or Thunderbolt to allow additional devices to connect.
• Wifi antennas are located in the bezel of a laptop screen.

Mobile Devices

• FRU is a Field Replaceable Unit referring to components like the motherboard, and LCD.
• Hotspot refers to a cell phone sharing its mobile connection across a WiFi Network.
• Bluetooth enables PAN access
• NFC provides contactless Payment Connections.
• Pairing are the steps required when two Bluetooth Devices connect.
• 2.5-inch is the standard width of a laptop Hard Drive.
• Tethering refers to Providing Internet to a Mobile Device by tethering a cell phone.
• LTE or 4G is the technology that provided improvements to 4G LTE.

Mobile Device Terms

• Identify the problem is done when asking open-ended questions.
• Airport mode means all cell and radio radios are turned off, but devices still are still functional .
• A plan of action comes after testing a theory.
• MIME provides email the ability to display pictures and Documents.
• A screen can be cleaned with water or appropriate cleaning solution.
• An Apple ID is required to setup or backup an Apple device.
• iTunes is the software used to synch Apple Devices.
• Verify Functionality refers to process of testing documentation

Printers

• Ink is the media for inkjet printers.
• MTBF is the mean time between failures.
• Ribbon is the media used by impact printers.
• ADF is an Automatic Document Feeder.
• Toner is the media used by laser printers.
• The Print Head often needs cleaning on an inkjet printer.
• Filament is a kind media used for 3-D printers.
• TCO is the Total cost of ownership.

Laser Printer Steps

• Laser Step 2 involves charging the drum so it is electrified to accept new images.
• Lease Step 7 is the cleaning step where excess toner is removed from drum
• Lease step 1 is processing and converting to printable format.
• Lease step 6 (fusing) is where heat and pressure fix the image on the paper.
• Lease step 4 is developing and applying toner to the drum.
• Lease Step 3 handles exposing the laser; here counter charge applies to drum in the form of print.
  • Thermal printers should not be used for archive purposes.
• Laser Step 5 is the transfer step to apply toner is to the paper by the drum.

Printers Setup and Config

• Collation organizes pages from print in print order and grouping.
• Printer Share is a way for a client machine, whose attached printer is made available to everyone else.
• Impact printers use impact to print and can print carbon copies.
• A print server is a dedicated machine that shares its printer to all the machines in network. It is not the print driver
• Duplexing describes printing on both sides of paper.
• A print driver is a small program acts the goes, acts as middle-man between printer AND and print.
• Testing out what is going on happens before establishing a plan of action
• Assessing or developing a theory on what will occur, happens towards the end and to properly inform testing to develop action.

Virtualization

• Type 2 is a hypervisor which runs on an OS, which in turn runs on another layer.
• A Hypervisor is a program which creates, configures and manages VM (Virtual Machine).
• SaaS is a Software as a Service, in which the user is not responsible for installation.
• Virtualization is the foundation for cloud computing.
• A guest OS is a OS run on guest (VM).
• Type 1 is a Hypervisor which bare metal as underlying without.
• IaaS handles Infrastructure, so the User gets OS support but responsible for everything else.
• PaaS helps programmers by creating, testing and managing virtual apps.

This lesson covers ATX form factors, voltage levels (3.3V, 5V, 12V), connectors like Molex, and the importance of ESD protection. It also explains the role of the PSU in converting AC to DC power. The lesson also discusses motherboards, RAM, northbridge, southbridge, BIOS/UEFI, CPUs and expansion slots.