CompTIA A+ 220-1201 9th Set of Videos

CapEx (Capital Expenditure)

A large upfront purchase of equipment that an organization owns; typical of private clouds.

OpEx (Operational Expenditure)

Ongoing monthly payments for services used; typical of public cloud models.

Ingress vs. Egress

Ingress is data entering a network; egress is data exiting (usually more expensive).

Elasticity

A system's ability to automatically scale resources up or down without human intervention.

Multi-tenancy

Cloud architecture where multiple customers share physical resources while keeping data logically private.

High Availability (HA)

Design goal ensuring system operation during failures via geographic redundancy across data centers.

POST (Power On Self-Test)

Motherboard self-check that runs before the OS loads; checks hardware readiness.

Beep Codes

Audible patterns used by motherboards to communicate errors when the screen is unavailable.

CMOS Battery / RTC

Powers the CMOS chip to maintain BIOS settings and the real-time clock when unplugged.

Thermal Throttling

CPU slows its clock speed to reduce heat output and prevent damage when overheating.

Thermal Paste (TIM)

Material that fills microscopic air gaps between the CPU and heat sink to improve conduction.

Capacitor (Failure)

Components that store charge; a bulge or leak indicates a chemical-driven hardware failure.

Reliability Monitor

Windows tool providing a friendly visual timeline of system stability and crash history.

Event Viewer

Windows utility for deep investigation of detailed raw log entries for every system event.

HDD Mechanical Components

Spinning magnetic platters and actuator arms with read/write heads that float nanometers above surfaces.

S.M.A.R.T.

Internal drive monitoring system that logs health data like reallocated sectors and temperature.

RAID 0 (Striping)

Splits data across drives for increased speed but offers zero fault tolerance.

RAID 1 (Mirroring)

Writes exact duplicates to two drives simultaneously for data protection.

RAID 5/6 (Parity)

Uses mathematical checksums to reconstruct data; RAID 6 tolerates two simultaneous drive failures.

RAID 10

A nested RAID level that mirrors first, then stripes the mirrors for speed and safety.

IOPS

Measures how fast a drive handles small random requests; critical for OS performance.

Mapped Network Drive

Shortcut where a remote server folder appears as a local drive letter (e.g., Z:\).

Native Resolution

The fixed physical grid of pixels on an LCD; running other resolutions causes blur.

Scaling

Adjusting the size of UI elements without changing the actual screen resolution.

LCD Burn-in

Degradation of liquid crystals in frequently-lit pixels, leaving a faint ghost image.

Pixel Shift

Mitigation technique that moves images by 1-2 pixels to prevent static element burn-in.

Metal Halide Bulb

High-intensity projector lamp that requires a cool-down cycle to prevent thermal shock cracking.

Hardware Acceleration

Offloading rendering tasks from the CPU to the GPU; disabling it helps diagnose driver issues.

Thermal Runaway (Battery)

Chemical decomposition in lithium batteries causing gas production and a swollen/bloated casing.

LCI (Liquid Contact Indicator)

Adhesive strip that permanently turns red when wet; used to identify liquid damage.

Desiccant

Substances like silica gel that use adsorption to actively pull moisture from devices.

Digitizer

The layer of a mobile display responsible for detecting touch input.

Active Stylus

Input pen with internal electronics and sensors that communicates directly with the device.

Mobile System Board

Highly integrated circuit board where CPU, RAM, and storage are typically soldered directly.

Loopback Address (127.0.0.1)

Pinging this tests the OS TCP/IP stack independently of physical hardware.

APIPA (169.254.x.x)

Self-assigned placeholder IP used when a device cannot reach a DHCP server.

Latency vs. Jitter

Latency is travel time; jitter is the inconsistency in arrival times between packets.

Traceroute

Utility that tracks a packet's path through every router (hop) to the destination.

SNR (Signal-to-Noise Ratio)

The ratio of desired wireless signal to background interference; >25 dB is good.

SLA (Service Level Agreement)

Contractual guarantee of performance, uptime percentage, and response times from a provider.

Port Flapping

Rapid up/down cycling of a physical ethernet port, often due to bad cables.

Photosensitive Drum

Laser printer component that holds an electrostatic charge where light hits it to attract toner.

Ghosting (Printer)

Faint 'echo' of a previous page caused by a failing drum cleaning blade.

PCL vs. PostScript

PCL provides step-by-step drawing instructions; PostScript describes pages mathematically as objects.

Print Spooler (spoolsv.exe)

Windows service that manages feeding print jobs to the printer in the background.

Pickup Rollers

Rubber wheels that feed paper; they cause multi-feeds or non-feeds when glazed or hardened.

Printer Finishing

Post-printing features like collating, stapling, and hole punching built into enterprise units.

Embedded Print Server

Web server inside a printer used to manage queues, toner, and settings via IP.