Lesson Notes

Full class notes for A+ Core 1 3.5: choosing between ATX, micro-ATX and Mini-ITX by size, slots, power and mounting.

27 Sept 2026

Full class notes for A+ Core 1 3.5: buses, PCI vs PCIe, parallel vs serial, PCIe lanes, and installing add-in cards safely.

27 Sept 2026

Full class notes for A+ Core 1 3.5: main and PCIe power connectors, SATA/eSATA data, front-panel and USB/TPM headers, and M.2.

27 Sept 2026

Full class notes for A+ Core 1 3.5: Intel vs AMD sockets, installing a CPU, and multisocket server motherboards.

27 Sept 2026

Full class notes for A+ Core 1 3.5: BIOS firmware, POST and boot, legacy BIOS vs UEFI, dual-BIOS flash, and settings.

27 Sept 2026

Full class notes for A+ Core 1 3.5: entering setup, boot order, USB control, fan and temperature, Secure Boot, passwords, CMOS reset and virtualisation.

27 Sept 2026

Full class notes for A+ Core 1 3.5: protecting cryptographic keys with a TPM (root of trust, BitLocker) and centralising them with an HSM.

27 Sept 2026

Full class notes for A+ Core 1 3.5: 32-bit vs 64-bit (x86/x64), ARM architecture, and multi-core CPUs.

27 Sept 2026

Full class notes for A+ Core 1 3.5: sound cards, discrete GPUs, capture cards, NICs, and driver install best practice.

27 Sept 2026

Full class notes for A+ Core 1 3.5: fans and airflow, passive cooling, heat sinks, thermal paste and pads, and liquid cooling.

27 Sept 2026

Full class notes for A+ Core 1 3.7: MFD setup, drivers, PCL/PostScript, connectivity, sharing, print features, secure printing, and scanning.

27 Sept 2026

Full class notes for A+ Core 1 3.8: the laser imaging process, toner/OPC drum, cartridge and maintenance-kit replacement, calibration, and cleaning.

27 Sept 2026

Full class notes for A+ Core 1 3.8: inkjet operation, CMYK cartridges, print heads, feed rollers, duplex, and (beyond the clip) carriage/belt and calibration.

27 Sept 2026

Full class notes for A+ Core 1 3.8: cleaning inkjet print heads, replacing CMYK cartridges, calibration, and clearing paper jams.

27 Sept 2026

Full class notes for A+ Core 1 3.8: how thermal printers work, the feed assembly and heating element, thermal paper care, and handling output.

27 Sept 2026

Full class notes for A+ Core 1 3.8: replacing thermal paper, cleaning the heating element, removing debris safely, and heat/fade sensitivity.

27 Sept 2026

Full class notes for A+ Core 1 3.8: dot-matrix print heads, ribbons, tractor-feed paper, and multi-part carbonless copies.

27 Sept 2026

Full class notes for A+ Core 1 3.8: ribbon replacement, print head replacement, and continuous tractor-feed paper handling on dot-matrix printers.

27 Sept 2026

Full class notes for TLCL ch. 8: readline cursor movement and editing, cut/paste (kill and yank), tab completion, and command history/expansion.

27 Sept 2026

Full class notes for TLCL ch. 9: users/groups/other, read/write/execute, chmod, umask, special permissions, su/sudo, chown/chgrp, and passwd.

27 Sept 2026

Full class notes for Networking for Sysadmins ch. 3: IPv4 addressing, subnets/netmasks, viewing config on Windows/Debian/FreeBSD, private addressing and NAT, and troubleshooting.

27 Sept 2026

Full class notes for MoL ch. 7: management shells, snap-ins vs modules, module discovery/import, profile scripts, and the PowerShell Gallery.

27 Sept 2026

Full class notes for MoL ch. 8: what objects are, Get-Member, properties and methods, Sort-Object, Select-Object, and format-last discipline.

27 Sept 2026

Full class notes for TryHackMe module 6: domain structure (TLD/SLD/subdomain), A/AAAA/CNAME/MX/TXT records, and the DNS resolution journey.

27 Sept 2026

Full class notes for TryHackMe module 7: HTTP/HTTPS, URL structure, requests and responses, HTTP methods, status codes, headers, and cookies.

27 Sept 2026

Full class notes for TryHackMe module 8: front end vs back end, HTML/CSS/JS, page source, sensitive data exposure, and HTML injection.

27 Sept 2026

Full class notes for TryHackMe module 9: load balancers, CDNs, databases, WAFs, web server software, virtual hosts, and static vs dynamic content.

27 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.1: LCD backlights, TN vs IPS vs VA, OLED, mini LED local dimming, touchscreens and digitizers, and inverters.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.1: pixel density and PPI maths, refresh rate and frames per second, resolution and aspect ratio, and colour gamut.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.2: twisted pair and why it is twisted, cable categories and distances, coax, UTP vs STP shielding codes, direct burial and plenum-rated cable.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.2: ANSI/TIA-568 and ISO/IEC 11801, the T568A and T568B pinouts, what differs between them, and wiring keystone jacks.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.2: how light travels through a fibre core and cladding, ferrules and connectors, and multimode versus single-mode fibre.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.2: USB versions and speeds, USB connector types and USB-C, DB-9 serial and RS-232 console access, and Thunderbolt 1 to 4.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.2: SATA revisions and speeds, the one-to-one SATA power and data connectors, and eSATA.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.2: DVI-D to HDMI and DVI-A to VGA compatibility, USB-to-Ethernet and USB-C-to-USB-A adapters, and USB hubs.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.2: RJ11 and RJ45, F connectors and DOCSIS, punchdown blocks, USB and USB-C, Molex, Lightning, and DB-9/RS-232.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.2: ST bayonet connectors, SC push-pull connectors, and compact LC connectors for optical fibre.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.3: RAM vs storage, DIMM and SO-DIMM, 64-bit data width, SDRAM, double data rate, and DDR3/DDR4/DDR5 compatibility and keying.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.3: parity memory and even-parity calculation, ECC memory, memory bandwidth in MT/s, and multi-channel RAM.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.4: hard drives and RPM, SSDs, PCIe and NVMe, SAS, mSATA and M.2 keying, flash memory formats, and optical drives.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.4: RAID 0 striping, RAID 1 mirroring, RAID 5 and RAID 6 parity, and nested RAID 1+0.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.6: power supply safety, AC vs DC, amps/volts/watts, regional voltage, the 24-pin connector, redundant PSUs, modular cabling, wattage sizing, and 80 PLUS efficiency.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 3.2: HDMI, DisplayPort and its locking connector, DVI variants and single/dual link, VGA, and video over USB-C.

24 Sept 2026

Full class notes for TLCL chapter 7: pathname, tilde, arithmetic, parameter and command expansion, then double quotes, single quotes and backslash escaping.

24 Sept 2026

Full class notes on PowerShell providers and PSDrives: what providers are, filesystem organisation, other data stores as drives, navigation, and wildcards vs literal paths.

24 Sept 2026

Full class notes on the PowerShell pipeline: connecting commands, exporting to CSV/XML, printing, ConvertTo-Html, system-modifying cmdlets, and common pipeline confusion points.

24 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 2.7: satellite (GEO vs LEO), fibre, cable and DOCSIS, DSL, cellular tethering and hotspots, and WISPs.

23 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 2.8: crimpers, Wi-Fi and spectrum analysers, tone generator and probe, punch-down tools, cable testers, loopback plugs, taps and port mirrors.

23 Sept 2026

Full class notes for TLCL chapter 6: standard input, output and error, redirecting and combining streams, /dev/null, group commands, pipelines and the filters uniq, wc, grep, head, tail and tee.

23 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 2.5: routers, managed and unmanaged switches, access points, firewalls, PoE and ISP devices.

22 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 2.6: IPv4 structure and binary, RFC 1918 private ranges and NAT, IPv6 notation and /64 prefixes.

22 Sept 2026

Full class notes for Professor Messer A+ 220-1201 objective 2.6: IP address, subnet mask and gateway; static addressing vs DHCP reservations; APIPA.

22 Sept 2026

Full class notes for Lucas, Networking for System Administrators (2nd ed.) ch. 1: the four network layers, encapsulation and troubleshooting layer by layer.

22 Sept 2026

Full class notes for Lucas, Networking for System Administrators (2nd ed.) ch. 2: interfaces, autonegotiation, MTU, ARP and Neighbor Discovery, VLANs and datalink errors.

22 Sept 2026

Full class notes for TryHackMe Pre Security (2026 path) module 5, What is Networking?: networks and the internet, IP and MAC addresses, and ping.

22 Sept 2026

Full class notes for TryHackMe Pre Security (2026 path) module 5, Intro to LAN: star, bus and ring topologies, switches and routers, subnetting, ARP and DHCP.

22 Sept 2026

Full class notes for TryHackMe Pre Security (2026 path) module 5, OSI Model: the seven layers, what each one does, TCP versus UDP, and encapsulation.

22 Sept 2026

Full class notes for TryHackMe Pre Security (2026 path) module 5, Packets & Frames: packets vs frames, the TCP/IP model, TCP headers and the three-way handshake, UDP and ports.

22 Sept 2026

Full class notes for TryHackMe Pre Security (2026 path) module 5, Extending Your Network: port forwarding, stateful and stateless firewalls, VPNs, routers, switches and VLANs.

22 Sept 2026

Exam tip: on the 220-1201 exam, display technologies (LCD, OLED, digitizers, inverters) moved to section 3 (Hardware). Section 1 is laptop hardware, connections and connectivity/management.

20 Sept 2026

A laptop packs a full computer into a very small space. That's why it's the standard platform for anyone on the move — but it's also why laptops are harder to service:

20 Sept 2026

Almost everyone in an organisation carries a phone, a tablet or both. Each device needs a way to connect back to computers and networks — and different devices have historically used different connectors and standards.

20 Sept 2026

Fingers work well for tapping and swiping, but they're imprecise. A digital stylus works like a pen or pencil on the screen, giving much finer, more granular control — for handwriting, drawing, annotating documents…

20 Sept 2026

An organisation may have hundreds or thousands of phones and tablets. Some are company-owned; others belong to employees. They're outside the office, easily lost, and each needs the right apps, email settings and…

20 Sept 2026

Data sent across a network is wrapped in layers, like envelopes inside envelopes (

20 Sept 2026

Note: this video doesn't map directly to an exam objective. Messer presents it as a primer: everything in the networking domain builds on it, so it's worth learning well.

20 Sept 2026

You'll use these port numbers in two everyday situations:

20 Sept 2026

When people say "wireless networking", they usually mean the network used at home or work to reach other devices and the internet. This is standardised by the IEEE — the Institute of Electrical and Electronics…

20 Sept 2026

A typical data centre holds rack after rack of equipment, with many different services running across those racks. This lesson works through the services you'd expect to find there — and several you'll meet…

20 Sept 2026

DNS (Domain Name System) is one of the most critical services on any network. It lets us provide IP addresses when all we remember is a fully qualified domain name (FQDN).

20 Sept 2026

Before automatic addressing, every device's IP configuration — IP address, subnet mask, default gateway, DNS servers and other settings — had to be entered manually. That was manageable with a small number of devices…

20 Sept 2026

A LAN (Local Area Network) is a group of devices connected together into a single broadcast domain. Send a broadcast from one device on that LAN, and every other device on that same LAN sees it.

20 Sept 2026

When you type a command, something has to read it, work out what you mean and ask the operating system to do it. That something is the shell: a program whose whole job is to take keyboard commands and pass them to…

20 Sept 2026

Linux, like Windows, organises files into a hierarchy of directories (folders) that can contain files and further directories. The first directory is the root directory, written /. Everything else branches out from it.

20 Sept 2026

Most commands follow the same general shape:

20 Sept 2026

A graphical file manager is fine for moving one file. But consider this task: copy every HTML file from one directory to another, but only files that don't exist in the destination or are newer than the copies there.…

20 Sept 2026

When you type a name at the prompt, it can be any one of four things:

20 Sept 2026

Graphical tools are good for doing one thing, once. They struggle with:

20 Sept 2026

PowerShell is two things working together:

20 Sept 2026

PowerShell has thousands of commands, and every module you install adds more. No one memorises them. Skilled PowerShell users are skilled at finding and reading help. The book is emphatic on this point: if you learn…

20 Sept 2026

Many people avoid PowerShell because they think it means "programming". But most day-to-day PowerShell is simply typing commands and pressing Enter, just as you would in CMD or Bash. A script is only a text file of…

20 Sept 2026

The Practical Help Desk course takes someone with no IT experience to the point where they can do the real work of a Tier 1 help desk technician. It's also the foundation TCM recommends before its more advanced…

20 Sept 2026

Information Technology (IT) is the people, processes and technology an organisation uses to create, store, move and protect information. In practice, IT exists to keep the business working. The payroll team needs…

20 Sept 2026

A computer is built from billions of tiny switches (transistors). A switch has two reliable states: off and on, which we write as 0 and 1.

20 Sept 2026

Electrostatic discharge (ESD) is the sudden flow of static electricity between two objects at different charge levels. You feel a shock at around 3,000 volts, but chips can be damaged by a few hundred — far below…

20 Sept 2026

Limited — RAM and storage sometimes; CPU and GPU almost never (soldered)

20 Sept 2026

An operating system (OS) manages the hardware and gives programs a consistent, safe way to use it. Without an OS, every application would need its own code to drive the disk, network card and screen — and nothing…

20 Sept 2026

Note: these notes are written from the module's topic outline, not from the rooms themselves. Room names and exercise specifics aren't reproduced — cross-check against the rooms as you work through them.

20 Sept 2026

Note: rooms in this module include Inside a Computer System and Computer Types. These notes are written from the module outline — cross-check room specifics as you go.

20 Sept 2026

Note: rooms in this module include Operating Systems: Introduction and Windows Basics, with Linux covered alongside. These notes are written from the module outline — cross-check room specifics as you go.

20 Sept 2026

Note: these notes are written from the module's topic outline (data representation, Python, JavaScript, databases and SQL). Cross-check room specifics as you go.

20 Sept 2026

13 Sept 2026

Why content-addressed keys dissolve most of the difficulty

8 Sept 2026