CompTIA 220-1101 A+ Course Overview by Professor Messer

SSD (Solid-State Drive)

Flash-based storage; faster and lower latency than HDDs.

SSD Repair Challenge

Compact, model-specific design makes repairs tricky.

M.2 SSD

Slot-based SSD that needs no SATA cables; easy install/replacement.

Laptop Battery (Purpose)

Primary power source when unplugged.

Laptop Battery (Care/Replace)

Capacity declines over time; replacement depends on model access.

Storage Replacement (General)

Ease varies by model—some have quick doors, others need full disassembly.

LCD

Liquid crystal panel that needs a backlight.

LED Backlight

More efficient and brighter than CCFL/fluorescent.

OLED

Self‑emissive pixels with rich color; can cost more.

TN Panel

Fast response, poor viewing angles.

IPS Panel

Accurate color and wide angles; pricier than TN.

VA Panel

High contrast; slower than TN, narrower than IPS.

Resolution

Pixel dimensions (e.g., 1920×1080) that affect clarity.

Aspect Ratio

Screen shape (e.g., 16:9) affecting layout and apps.

Touchscreen

Adds touch input; different troubleshooting from non‑touch.

Display Connections: HDMI

All‑digital audio/video; common external display port.

Display Connections: DisplayPort

Packetized digital video; can adapt to HDMI/DVI.

Common Display Issues

Flicker, lines, dead pixels, dim backlight, no image.

USB

Wired standard for data and charging.

Micro-USB

Older small USB for phones; mostly replaced.

USB-C

Reversible 24‑pin connector carrying data, power, and alt‑modes.

MTP

Media Transfer Protocol for files on mobile devices.

PTP

Picture Transfer Protocol; camera‑style file transfers.

Bluetooth

Short‑range wireless for peripherals (PAN).

Wi‑Fi

Wireless LAN for internet and local access.

NFC

Very short‑range tap‑to‑pair or pay; tiny data payloads.

Lightning

Apple proprietary connector; reversible.

Serial RS‑232 (DB‑9)

Legacy serial interface for consoles/devices.

Docking Station

Adds desktop ports and power for a laptop.

Port Replicator

Simpler dock; expands I/O via USB with fewer features.

2G

Voice‑centric GSM/CDMA with minimal data.

3G

Adds usable mobile data and multimedia.

4G/LTE

Mobile broadband with high data rates and low latency.

5G

Very high throughput and low latency; supports IoT/edge use.

CDMA vs GSM

Different 2G/3G families; GSM uses SIM widely.

Roaming

Using partner towers outside home network; affects coverage/costs.

SIM Card

Holds subscriber identity for network access.

IPv4

32‑bit addressing (e.g., 192.168.1.10).

IPv6

128‑bit addressing (e.g., fe80::1); huge address space.

Public IP

Globally routable on the internet.

Private IP

RFC1918/4193 ranges; not routed on the internet.

Subnetting

Dividing networks to manage addresses and broadcasts.

Static IP

Manually set; consistent address for servers/printers.

Dynamic IP

Assigned automatically (DHCP).

DHCP

Service that leases IP config to clients automatically.

FTP

tcp/20,21 – File transfers; auth required.

SSH

tcp/22 – Encrypted remote shell.

Telnet

tcp/23 – Insecure remote shell; avoid in production.

SMTP

tcp/25 – Send email between servers.

DNS

udp/tcp/53 – Name resolution.

DHCP (Ports)

udp/67,68 – Address assignment.

HTTP

tcp/80 – Web (unencrypted).

HTTPS

tcp/443 – Web with TLS encryption.

POP3

tcp/110 – Download email to client.

IMAP4

tcp/143 – Server‑side mail access/sync.

SMB

tcp/445 – Windows file/print sharing.

SNMP

udp/161,162 – Device stats (queries/traps).

LDAP

tcp/389 – Directory services.

RDP

tcp/3389 – Remote desktop.

Router

Routes between IP subnets; may do NAT/VPN.

Switch

Layer 2 forwarding by MAC; VLANs on managed models.

Firewall

Filters traffic by rules/ports; may do IDS/IPS.

Wireless Access Point

Provides Wi‑Fi for clients.

Modem

Converts service (cable/DSL/fiber) to Ethernet.

NIC

Network Interface Card; provides network port.

Patch Panel

Terminates cables for easy cross‑connects.

PoE

Power over Ethernet to run devices via network cable.

Managed Switch

Configurable (VLANs, QoS, trunks, monitor).

Unmanaged Switch

Plug‑and‑play with no config.

SDN (Concept)

Separates control plane from data plane.

SDN Control Plane

Centralized logic that programs forwarding.

SDN Data Plane

Fast path that forwards frames/packets.

OpenFlow

Common SDN protocol to program switches.

Network Virtualization

Abstracts networks for flexible allocation.

Ethernet Cable Types

Twisted pair: Cat5e, Cat6, Cat6A, etc.

Coaxial Cable

Shielded single conductor (e.g., RG‑6).

Fiber Optic

Transmits light; immune to EMI.

Cable Length Limits

Follow spec to maintain signal integrity.

Cable Testing

Use testers/TDR to validate wiring.

Install Best Practices

Label, route cleanly, respect bend radius.

Single‑Mode Fiber

Long distance, small core, laser source.

Multi‑Mode Fiber

Shorter distance, larger core, LED/VCSEL.

SC Connector

Square push‑pull fiber connector.

LC Connector

Small form‑factor latch fiber connector.

OTDR

Tests fiber for breaks/attenuation via backscatter.

HDD

Spinning platters; high capacity, slower.

SSD

No moving parts; very fast access.

Hybrid Drive

HDD with flash cache to speed reads.

SATA

Common storage interface for HDD/SSD/ODD.

SCSI/SAS

Enterprise storage bus; high performance.

Backup (Local/Cloud)

Protects data against loss/failure.

Storage Troubleshooting

Check SMART, cables, power, firmware.

ATX

Common full‑size motherboard form factor.

MicroATX

Smaller ATX variant with fewer slots.

Mini‑ITX

Very small board for compact builds.

PCIe

Serial expansion bus with x1–x16 lanes.

BIOS

Legacy firmware; limited features.

UEFI

Modern firmware; faster boots, >2 TB drives.

24‑pin ATX Power

Main motherboard power connector.

4/8‑pin CPU Power

Extra 12V power for the processor.