CompTIA A+ Core 1 (220-1201) flashcards

When a 'No Boot Device Found' error occurs despite the boot drive being detected in BIOS/UEFI and the boot order being correct, it typically indicates a corrupted boot sector or Master Boot Record (MBR) on the drive.

• Drive is physically recognized
• Boot order is correct
• OS cannot initiate boot process
• Often requires boot repair tools

Memory trick: Boot Records are Broken, so Repair Boot.

Calculating whether host hardware resources (RAM, CPU) can support planned VM workloads plus hypervisor overhead.

• Always account for hypervisor/management overhead
• Sum all VM resource requirements before comparing to host capacity
• Overcommitting RAM can degrade VM performance

Memory trick: Add up VMs + hypervisor overhead, then compare to total host RAM.

Occurs when one network device is set to full-duplex and the connected device is set to half-duplex, causing collisions and degraded performance.

• Half-duplex expects collisions; full-duplex does not handle them
• Symptom: excessive collisions/late collisions with intermittent loss
• Fix: match duplex/speed settings, or use auto-negotiation on both ends

Memory trick: Two speakers talking at once (full) vs. taking turns (half) — mismatched, they collide.

The process of moving a running VM from one physical host to another with little to no downtime, often used for maintenance or load balancing.

• Requires shared storage or fast network transfer between hosts
• Preserves VM state and active connections
• Common feature in enterprise hypervisors (e.g., vMotion, Hyper-V Live Migration)

Memory trick: Live migration is a moving truck that never stops the show.

The seven-step laser print process: processing, charging, exposing, developing, transferring, fusing, and cleaning.

• Fusing uses heated rollers to bond toner permanently
• Skipped/failed fusing causes smearing or loose toner
• Order matters: develop → transfer → fuse

Memory trick: Perfect Cats Eat Dinner Two Fridays a Cleaning

WPA3 is the newest Wi-Fi security standard that uses Simultaneous Authentication of Equals (SAE) to protect against offline password-guessing attacks.

• Successor to WPA2
• Uses SAE instead of PSK 4-way handshake
• Resists offline dictionary attacks

Memory trick: WEP weak, WPA weaker fix, WPA2 good, WPA3 great.

Audible codes generated by system firmware during Power-On Self-Test to indicate hardware failures before video output is available.

• Continuous beeping often indicates RAM failure
• Beep patterns vary by BIOS manufacturer (AMI, Award, Phoenix)
• No beep at all with no display may indicate PSU or motherboard failure

Memory trick: 'Beeping Means Bad Memory' when video card is fine.

A Bluetooth profile that enables the transmission of high-quality stereo audio from a source device to a receiving device like speakers or headphones.

• Used for music/audio streaming
• Different from HID (input devices) and PAN (networking)
• Part of the Bluetooth Classic profile suite

Memory trick: 'A2DP = Audio to Distant Player'

A hypervisor installed directly on physical hardware (bare metal) without a host operating system, commonly used in enterprise data centers.

• Examples: VMware ESXi, Microsoft Hyper-V (server core), Citrix Hypervisor
• Better performance and security than Type 2
• Used for production virtualization hosts

Memory trick: Type 1 = 'one layer only' (hardware + hypervisor).

The core component in a laser printer that uses electrostatic charges to attract toner in the pattern of the image to be printed.

• It's a photosensitive component, often a cylinder.
• Defects like scratches on the drum directly translate to repeating marks on printouts.
• Often integrated into the toner cartridge or a separate drum unit.

Memory trick: For print defects, remember 'D.T.F.C.' - Drum, Toner, Fuser, Corona.

Common indicators of a failing power supply unit include intermittent power, unexpected shutdowns, system instability, or complete failure to power on.

• Flickering power LEDs or fans briefly spinning are strong indicators.
• Can manifest as random reboots or system freezes.
• Often mistaken for other component failures, but specific power symptoms point to the PSU.

Memory trick: When it won't boot, check 'P.C.R.D.' - Power, Cables, RAM, Display.

Remote Desktop Protocol uses TCP port 3389 to provide full graphical remote access to a Windows computer.

• Native to Windows Remote Desktop feature
• Should be secured with strong passwords or VPN due to attack risk
• Differs from SSH, which is command-line only

Memory trick: RDP: remote desktop, port thirty-three eighty-nine.

A service (e.g., Google, iCloud) that automatically keeps data like contacts, calendars, and settings consistent across all devices signed into the same account.

• Works over internet, not local connection
• Common for contacts, photos, calendar, app data
• Requires the same account signed in on all devices

Memory trick: Same account, same cloud — changes ripple to every device.

When a PC powers on but produces no beeps and no display, technicians should check simple causes like RAM seating before replacing major components.

• Power/fans on ≠ successful POST
• Reseat RAM and expansion cards first
• Escalate to PSU/motherboard only after ruling out simple causes

Memory trick: When in doubt, reseat it out (and back in).

Determining the total amount of available RAM by multiplying the number of installed memory modules by the capacity of each module.

• Motherboard specifications dictate maximum total RAM and number of slots.
• Memory modules must be compatible with the motherboard's RAM type (e.g., DDR4).
• Populating all available slots is often done to maximize capacity or utilize multi-channel memory architectures.

Memory trick: To calculate RAM, 'Slots' times 'Size' equals 'Total'.

A maintenance procedure, often software-driven, that flushes ink through the nozzles of an inkjet print head to clear clogs and restore print quality.

• Typically accessed through the printer's control panel or software utility.
• Uses ink, so repeated cleaning can deplete cartridges.
• Often resolves streaking, missing lines, or incorrect colors.

Memory trick: Clean Clogged Channels Carefully.

RJ11 is a small modular connector, typically with 4 or 6 pins, used for analog telephone connections.

• Used for telephone lines, not Ethernet
• Smaller than RJ45
• Usually uses only 2 of the available pins for voice

Memory trick: RJ11 = 'eleven' pins are fewer, for phones not computers.

Subnet size is determined by host bits; usable hosts = 2^n - 2, where n is the number of host bits remaining after the mask.

• /26 = 62 usable hosts
• /27 = 30 usable hosts
• Choose smallest subnet that still meets host requirement to minimize waste

Memory trick: Subtract 2 for network/broadcast, then check if it fits.

A docking station adds extra ports and capabilities beyond the laptop's native connections, while a port replicator simply duplicates existing native ports.

• Docking stations often add extra video outputs and Ethernet
• Port replicators are simpler and cheaper
• Both connect via a single proprietary or USB-C connector

Memory trick: Docking stations 'dock' extra features; replicators just 'replicate' what's there.

A loopback plug is a small hardware device inserted into a network or serial port that redirects outgoing signals back as incoming signals, used to test port functionality.

• Tests NIC send/receive capability in isolation
• Common for Ethernet and serial port diagnostics
• No actual network cable or switch connection required

Memory trick: Loopback: what goes out comes right back in.

DDR5 memory operates at a lower standard voltage (1.1V) than DDR4 (1.2V), improving power efficiency while increasing bandwidth and capacity.

• DDR4 = 1.2V standard voltage
• DDR5 = 1.1V standard voltage
• DDR5 is not backward compatible with DDR4 slots

Memory trick: Each new DDR generation sips less power while sipping faster data

A condition where a network printer's internal software services (e.g., print server, web server) fail, preventing it from processing print jobs or responding to management interfaces, despite basic network connectivity.

• Printer is pingable but not functional.
• Web interface is often inaccessible.
• Control panel may show 'Ready' or a generic status.

Memory trick: If the printer pings but won't print or show its web page, its internal brain (service) is asleep.

When a charging source (like a dock) supplies less wattage than a device requires, the device may charge slowly or drain its battery under load rather than being damaged.

• USB-C PD negotiates the highest wattage the charger can supply, up to its max rating
• If device power draw exceeds supply, battery makes up the difference
• Common issue: 60W dock cannot fully power a 65W-required laptop under heavy use

Memory trick: '60 can't cover 65 — battery picks up the slack'

Thin coaxial cables that route wireless signal from antennas embedded in the display bezel to the Wi-Fi card in the laptop base.

• Usually black and white/gray coax pairs
• Must be reconnected carefully during screen replacement
• Antennas placed in bezel for better reception away from metal chassis

Memory trick: Thin coax wires whisper Wi-Fi from the bezel to the brain.

A short-range wireless technology (a few cm) used for contactless payments, tap-to-pair, and data exchange.

• Range under ~4 cm
• Used in mobile payment apps like Apple Pay/Google Pay
• Also used for tap-to-pair Bluetooth speakers/headphones

Memory trick: NFC = 'Near Fast Cash' — tap and pay

A storage allocation method where virtual disks are assigned a maximum size but only consume physical storage as data is actually written, allowing total allocated space to exceed physical capacity.

• Allocated capacity can exceed physical capacity (overcommit)
• Requires ongoing monitoring to avoid the datastore filling up
• Opposite of thick provisioning, which reserves full space upfront

Memory trick: Thin provisioning is like overbooking a flight — fine until everyone shows up.

Interfaces designed to provide very fast data transfer rates for storage devices, crucial for applications handling large files or requiring low latency.

• PCIe-based NVMe SSDs offer the highest performance for internal storage.
• Thunderbolt and USB 3.2 Gen 2x2 offer high speeds for external storage.
• SATA III is a common but slower interface for traditional SSDs and HDDs.

Memory trick: For speed, 'P.S.U.F.' for PCIe, SATA, USB, FireWire.

Software tools designed to test the integrity and functionality of RAM modules by performing various read/write patterns and checks.

• Identifies faulty RAM modules.
• Runs comprehensive tests.
• Can be bootable from USB or included in OS.

Memory trick: Memory errors? Diagnostic software knows the answers.

A security method requiring a second verification factor beyond a password to authenticate device enrollment in an MDM system.

• Reduces risk from stolen or guessed passwords
• Common second factors include SMS codes or authenticator apps
• Widely recommended for securing administrative and enrollment portals

Memory trick: 2FA = two locks on the enrollment door, not just one key.

A firewall (on the printer, a server, or client) that is preventing communication over the specific ports used for network printing services.

• Printer is reachable by ping, but print jobs fail.
• Common ports: TCP 9100 (Raw), TCP 515 (LPR), UDP 161/162 (SNMP).
• Requires checking firewall rules on all involved devices.

Memory trick: If the printer 'pings' but 'pages' don't flow, check the 'firewall' to see why they don't go.

A network problem where a computer cannot translate human-readable domain names (e.g., google.com) into numerical IP addresses.

• Prevents web browsing and access to resources by name.
• Ping to IP addresses often works, while ping to domain names fails.
• Caused by incorrect DNS server settings, faulty DNS server, or firewall blocking DNS traffic.

Memory trick: If you know the 'address' but not the 'name', DNS is the one to blame.

A cable tester (or certifier) verifies network cable installations by checking continuity, correct wire mapping/pinout, and identifying faults like shorts, opens, and split pairs.

• Certifiers can also measure performance metrics like attenuation and crosstalk
• Basic testers check wiremap and continuity only
• Different from tone/probe, which locates cables rather than verifying wiring quality

Memory trick: Certifier checks it ALL: continuity, pinout, and faults.

A systematic approach to diagnosing why a computer powers on but displays no image on the screen.

• Check physical connections first (cables, power).
• Listen for beep codes to identify hardware failures.
• Test with known-good components (monitor, cable, GPU).

Memory trick: See No Screen? Start Simple Solutions.

A common cloud sync strategy where the most recently submitted change to a record overwrites earlier, unsynced changes made on another device.

• Offline edits can be lost if another device syncs a newer version first
• Common in contact, calendar, and file sync services
• Users should sync frequently to minimize conflicting offline edits

Memory trick: 'Last one to sync writes the story'

When a client's dynamically assigned IP address lease from a DHCP server expires, and the client fails to renew it, leading to a loss of network connectivity or obtaining a new address.

• Clients periodically attempt to renew their DHCP leases.
• Failure to renew can cause intermittent connectivity.
• Symptoms include loss of IP address or obtaining a new one.

Memory trick: When the network connection comes and goes, and the IP address changes, think about the DHCP lease expiring and renewing.

A system (e.g., Kubernetes) that automates the deployment, scaling, scheduling, and health management of containers across a cluster of hosts.

• Kubernetes is the most widely used orchestration platform
• Automatically restarts failed containers
• Manages scaling and load distribution across nodes

Memory trick: Orchestration conducts an army of containers like a symphony.

A malfunction of the touchscreen layer that detects touch input, while the underlying display panel remains functional.

• Symptoms include an unresponsive or inaccurate touchscreen.
• The display itself typically shows images normally.
• Often requires replacement of the entire screen assembly (LCD+digitizer).

Memory trick: If you can see the screen but can't touch it, the digitizer has gone silent.

A situation where virtual machines are created faster than they can be managed or decommissioned, resulting in unused VMs wasting resources and licenses.

• Caused by lack of lifecycle management
• Wastes storage, CPU, and licensing costs
• Mitigated by VM inventory audits and governance policies

Memory trick: Forgotten VMs become zombie machines haunting your host.

Containers virtualize at the operating system level, sharing the host kernel, while VMs virtualize hardware and each run a full separate guest OS.

• Containers start faster and use fewer resources than VMs
• VMs provide stronger isolation via separate kernels
• Container engines: Docker, Podman; orchestration: Kubernetes

Memory trick: Containers share the kitchen (kernel); VMs bring their own kitchen (full OS).

A cloud deployment model shared by several organizations with common concerns such as compliance or security requirements.

• Not open to the general public
• Shared among organizations with similar needs
• Common in healthcare, government, or finance sectors

Memory trick: Community cloud is a shared clubhouse for similar organizations.

Intermittent network connectivity issues on a single workstation, while other devices on the same network function correctly, strongly suggest a problem with the workstation's Network Interface Card (NIC) or its driver.

• Problem isolated to one device
• Sporadic disconnections/reconnections
• NIC is responsible for physical network communication
• Driver issues can also cause this

Memory trick: NIC is Nasty, Causing Connectivity Chaos.

Diagnosing issues with a network interface card (NIC) that is built directly into the motherboard, often involving checking BIOS settings, drivers, and physical connections.

• Integrated NICs can be enabled or disabled in the system's BIOS/UEFI settings.
• Lack of link lights indicates a physical or hardware-level issue.
• Driver issues can prevent OS detection, but a BIOS disablement would also prevent it.

Memory trick: When NIC won't 'Link', check 'B.C.D.H.' - BIOS, Cables, Drivers, Hardware.

Damage to the internal conductive traces or membrane layers within a keyboard, preventing specific key presses from being registered.

• Causes certain keys or groups of keys to become unresponsive.
• Often occurs without visible external damage.
• Requires keyboard replacement as a fix.

Memory trick: If 'some' keys are silent, the 'matrix' is broken, not just a tenant.

White horizontal lines in inkjet prints typically result from dried or clogged print head nozzles; running the cleaning utility is the standard remedy.

• Banding = missing ink lines from clogged nozzles
• Built-in cleaning cycles flush dried ink
• Persistent clogs may require print head replacement

Memory trick: Banding lines mean nozzles need a shower — run the cleaning cycle.

A cloud deployment model where infrastructure and services are owned by a third-party provider and shared among multiple unrelated customers over the internet.

• Multi-tenant environment shared by many customers
• Customer has no control over underlying physical hardware
• Typically billed on a pay-as-you-go or subscription basis

Memory trick: Public cloud = 'Public pool' shared by everyone, no lifeguard control.

Rapid battery drain in a laptop with a healthy battery often indicates excessive power consumption by software, background processes, or misconfigured power settings.

• Software/OS is a common cause
• Background apps prevent sleep modes
• Check power settings and running processes

Memory trick: Software Sucks Power, so Stop Spurious Services.

This error occurs when firmware cannot locate a valid boot loader/MBR/GPT boot record on the designated boot drive, even if the correct drive is selected.

• Confirm boot order in BIOS/UEFI first
• Corrupted MBR/boot sector is a leading cause
• Repair using tools like bootrec (Windows) from recovery media

Memory trick: 'No OS Found, Fix the Record.'

Standardized dimensions and layouts for motherboards, determining compatibility with cases, power supplies, and component capacity.

• ATX is common for desktops.
• Mini-ITX for compact builds.
• E-ATX for high-end workstations/servers (often dual CPU).
• Form factor dictates physical size and available features.

Memory trick: Size matters: E-ATX for extra power, compact for less tower.

A hand tool used to attach RJ45 (or RJ11) connectors to the end of a cable by pressing metal contacts through the wire insulation.

• Used when building custom-length patch cables
• Different from punch-down tools used for jacks/patch panels
• Follows a wiring standard like T568A or T568B

Memory trick: Crimp the plug, punch the jack.

Tethering shares a mobile connection via USB or Bluetooth to one device; a hotspot broadcasts Wi-Fi to multiple devices.

• Tethering often uses USB or Bluetooth
• Hotspot uses Wi-Fi broadcast
• Both consume mobile data plan allowances

Memory trick: Tether = tied by a cable; hotspot = floats wirelessly.

Sudden, significant drops in a mobile device's reported battery percentage, especially from a moderate charge, usually indicate degraded battery cells or a miscalibrated battery management system.

• Battery reports incorrect charge
• Cells can't hold consistent voltage
• Often requires battery replacement or recalibration

Memory trick: Degraded Cells Cause Crazy Counts.

A power supply that is no longer delivering stable and consistent power to system components, leading to unpredictable behavior.

• Can cause random reboots, system crashes, and varying BSOD errors.
• Symptoms are often intermittent and difficult to diagnose.
• May also manifest as components failing to power on or system not booting.

Memory trick: Unstable power makes a computer's mind go blank.

A router feature that prioritizes certain network traffic types (e.g., VoIP, gaming) over others to improve performance for time-sensitive applications.

• Reduces latency/jitter for prioritized traffic
• Common uses: VoIP, video conferencing, gaming
• Configured in SOHO router admin settings

Memory trick: QoS = 'Quiet other stuff, Speak first!' for VoIP.

Automatic Private IP Addressing assigns a host an address in the 169.254.0.0/16 range when it cannot obtain an address from a DHCP server, indicating a network or DHCP problem.

• Range: 169.254.0.1 to 169.254.255.254
• Indicates DHCP server unreachable
• Also called link-local address (self-assigned)

Memory trick: 169.254 means 'I gave up waiting for DHCP.'

A malfunctioning power supply that fails to deliver stable and sufficient electrical power to the computer components.

• Can cause intermittent power-on issues.
• Symptoms include flickering power LEDs, repeated short beeps, or no power at all.
• Often requires replacement to resolve.

Memory trick: Power problems often start with the supply, making the lights flicker and the system beep repeatedly.

A VDI endpoint device with no local operating system or storage that relies entirely on the remote server to render and process the desktop session.

• Simpler hardware than thin clients
• No local OS to patch or manage
• Contrasts with thin clients, which run a minimal local OS

Memory trick: Zero client has zero brains — the server does all the thinking.

A transparent touch-sensing layer overlaid on a display that translates finger/stylus contact into input signals.

• Separate component from the LCD/OLED panel
• Failure causes unresponsive touch while display still works
• Often fused with the glass in modern devices

Memory trick: Digitizer 'digs' into your touch, LCD just shows the picture

A PSU failure occurs when the power supply cannot deliver stable and sufficient electrical power to the system components, often leading to instability or shutdowns.

• Common symptoms include unexpected shutdowns, reboots, or failure to power on.
• Can be caused by insufficient wattage, component degradation, or power surges.
• Often manifests under high system load when components draw maximum power.

Memory trick: Shutdowns under load often mean the 'Power' is out of 'Supply'.

An MDM feature that uses location boundaries to trigger automated actions like locking a device or alerting staff.

• Relies on GPS/network location tracking
• Common for asset protection and compliance
• Can trigger lock, wipe, or notification actions

Memory trick: Geofence = invisible fence that locks the device if it wanders off.

Damage or loose connection of the internal video cable (LVDS) that connects a laptop's display panel to its motherboard.

• Often causes intermittent flickering, color distortion, or black screens.
• Symptoms are usually triggered or worsened by opening/closing the lid or moving the laptop.
• Requires disassembling the laptop to inspect and potentially replace the cable.

Memory trick: When the screen's wiggly, the cable's jiggly.