1202 From First set of 10th Set

Kernel

The innermost core of an OS that directly controls hardware and memory allocation.

Open source

Software whose source code is publicly readable, modifiable, and distributable.

Closed source

Proprietary software where only the vendor can inspect, modify, and update the code.

Linux distribution (distro)

A package containing the Linux kernel, a package manager, and desktop environments.

SDK (Software Developer's Kit)

A complete toolkit used by developers to write applications for a specific platform.

Virtual memory (paging/swap)

Storage drive space used as slow, temporary RAM when physical RAM is full.

End of Life (EOL)

The date when a vendor stops providing security patches and updates for software.

Open Handset Alliance

A Google-led group formed to design Android for diverse hardware compatibility.

Partition

A logical division of a physical drive that functions as a separate volume.

Quick format vs. Full format

Quick writes a new file index; full writes zeros and checks for bad sectors.

Journaling

A file system feature logging changes before writing them to prevent data corruption.

Fragmentation

The scattering of file parts across an HDD, which slows read/write times.

exFAT

A modern file system for flash drives that bypasses FAT32's 4 GB file limit.

APFS snapshot

A read-only, point-in-time state of a file system that only tracks block changes.

PXE (Preboot Execution Environment)

A standard allowing computers to boot and install an OS over a network connection.

ISO image

A single file containing a bit-for-bit, exact copy of an entire optical disc.

Master Boot Record (MBR)

An older partition style limited to four primary partitions and 2 TB drive sizes.

GUID Partition Table (GPT)

A modern partition style using 128-bit unique identifiers and supporting drives over 2 TB.

UEFI

The modern BIOS replacement supporting Secure Boot, GUI interfaces, and larger drives.

Secure Boot

A UEFI security feature that checks digital signatures on bootloaders to block rootkits.

Zero-touch deployment

An automated enterprise OS installation process requiring no manual technician interaction.

diskpart

A powerful Windows command-line utility used for managing disks and partitions.

TPM (Trusted Platform Module)

A dedicated motherboard microchip that securely stores hardware-rooted cryptographic keys.

BitLocker

Windows' built-in full-disk encryption software, which typically requires a TPM.

Windows Hello

A biometric authentication system that secures templates directly inside the TPM.

Quality updates vs. Feature updates

Quality updates are critical security patches; feature updates add new OS capabilities.

Modern Lifecycle Policy

Microsoft's support policy requiring users to keep updating to remain officially supported.

msinfo32

A Windows tool displaying comprehensive details about hardware, software, and BIOS.

Active Directory (AD)

A Windows Server directory service used to manage users, computers, and security policies.

Group Policy

An Active Directory mechanism used to push settings to domain-joined Windows PCs.

Remote Desktop Protocol (RDP) restriction

Windows Home can connect to other PCs but cannot accept incoming RDP connections.

AppLocker

An administrative tool used to whitelist or blacklist specific executable files from running.

BranchCache

An enterprise feature caching WAN-delivered files locally at branch office locations.

MDM vs. MAM

MDM manages the entire device; MAM controls only specific corporate applications.

Ctrl + Shift + Escape

The fastest direct keyboard shortcut to open the Windows Task Manager.

Services (Task Manager)

Background programs supporting Windows functions, security, and networking.

Startup Tab

A Task Manager tab used to manage and disable auto-starting boot applications.

Microsoft Management Console (MMC) executable

mmc.exe

Event Viewer run command

eventvwr.msc

Disk Management run command

diskmgmt.msc

Task Scheduler run command

taskschd.msc

Device Manager run command

devmgmt.msc

Certificate Manager run command

certmgr.msc

Performance Monitor run command

perfmon.msc

Local Group Policy Editor run command

gpedit.msc

Domain Group Policy Management Console run command

gpmc.msc

Interrupt Request (IRQ)

A hardware channel used by devices to signal the CPU for immediate attention.

Direct Memory Access (DMA)

A feature allowing hardware to transfer data directly to RAM without involving the CPU.

Registry hive

A top-level subdivision of the Windows registry saved as a physical file on disk.

User Account Control (UAC)

A security boundary requiring explicit confirmation before running programs with elevated privileges.

HKEY_LOCAL_MACHINE (HKLM)

The registry hive containing machine-wide hardware, software, and system configuration settings.

Resultant Set of Policy (RSOP)

The final combined Group Policy settings applied to a user or computer.

CBS.log (Cabinet Staging log)

The log file that records detailed actions and repairs made by SFC.

Robocopy /IPG switch

Adds an Inter-Packet Gap to throttle bandwidth during file transfers.

Sleep vs. Hibernate

Sleep stores state in RAM (low power); Hibernate saves state to disk (no power).

Active Directory time requirement

Client machines must have synchronized system time for authentication to succeed.

Hidden administrative share naming convention

Append a dollar sign ($) to the end of the share name.

Workgroup vs. Domain

Workgroups use local peer-to-peer authentication; domains use centralized authentication via Active Directory.

TCP (Transmission Control Protocol)

Connection-oriented protocol; recipient confirms delivery (like a certified letter).

UDP (User Datagram Protocol)

Connectionless protocol; faster transmission but no delivery confirmation.

Port 80

The port number used for unencrypted HTTP web traffic.

Port 443

The port number used for encrypted HTTPS web traffic.

Inbound vs Outbound Rules

Inbound controls incoming traffic (knocking); outbound controls outgoing traffic (leaving).

Firewall Disposition

The action taken on traffic: Allow, allow-if-secure, or block.

Connection Security Rules

Advanced firewall rules using IPsec to encrypt and authenticate traffic.

Subnet Mask

Defines which part of an IP address is the network and which is the host.

Default Gateway

The router address used to send traffic outside the local subnet.

Loopback Address (127.0.0.1)

Also called localhost; tests if the local TCP/IP stack is running.

DNS (Domain Name System)

Resolves human-readable domain names to machine-readable IP addresses.

VPN Concentrator

Dedicated device terminating many remote VPN connections simultaneously.

802.1X

An authentication standard that verifies wireless users against a RADIUS server.

PSK vs Enterprise Wi-Fi

PSK uses one shared password; Enterprise uses individual user credentials.

Proxy vs VPN

Proxy filters and inspects content; VPN encrypts all traffic end-to-end.

net use command format

net use [drive letter]: [\\server\share]

macOS Tilde (~) symbol

Shorthand for the current user's home directory.

macOS .app Bundle

A directory containing all application files, treated as one object in Finder.

MDM (Mobile Device Manager)

Platform used by IT to push policies and manage macOS/iOS devices remotely.

Rapid Security Response (RSR)

Targeted macOS security patches pushed quickly, indicated by a letter suffix (e.g., 14.4a).

Active Directory Integration (macOS)

Allows macOS users to log in using corporate Windows domain credentials.

WINS (Windows Internet Naming System)

Legacy protocol resolving NetBIOS names to IP addresses on Windows networks.

IPv4 vs IPv6

IPv4 uses 32-bit addresses (limited); IPv6 uses 128-bit addresses (unlimited).

macOS Accessibility Permission

High-security permission required by keyloggers and screen recorders to function.

Print Queue

List of pending print jobs; cleared first when troubleshooting a stuck printer.

macOS Keychain

OS-level manager storing passwords and digital certificates for authentication.

macOS Spaces

Virtual desktops used to organize different application windows on one screen.

AirDrop Connection Requirements

Uses Bluetooth to establish connection, then direct Wi-Fi to transfer files.

FileVault

Full disk encryption protecting macOS data at rest.

Shell Script

Plain text file containing automated sequential terminal commands.

Force Quit vs Restart

Force quit kills one frozen app; restart reboots the entire OS.

Linux /etc/shadow

Stores secure password hashes, readable only by root (unlike /etc/passwd).

Password Hashing

One-way mathematical function converting passwords to fixed-length strings.

Kernel Space vs User Space

Hardware-enforced separation preventing user app crashes from taking down the OS.

Linux /etc/hosts

Local file mapping hostnames to IPs; takes priority over DNS.

systemd

Modern Linux init system starting services in parallel for faster boots.

UEFI vs Legacy BIOS

UEFI supports >2TB drives, Secure Boot, and graphical interfaces.

Linux chmod Permission Values

read = 4, write = 2, execute = 1.

chmod 744 Permissions

User: read/write/execute (7), Group: read (4), Others: read (4).

grep vs. find

grep searches inside files; find searches for files by name.

rm -r

Deletes a directory and its contents recursively with no undo.

sudo vs. su

sudo runs one elevated command; su switches the entire session to root.