Definitions Flashcards
(17 cards)
What is ESD?
Electrostatic Discharge, the passage of static electrical charge from one item to another.
Registered Memory
Buffered Memory
Device Driver
Active power factor correction (active PFC)
Good PC power supplies come with (active PFC), extra circuitry that smooths out the power coming from the wall before passing it to the main power supply circuits.
AAA (Authentication, Authorization, and Accounting)
- Authentication
What it is: Verifying the identity of a user, device, or system.
How it’s done: Through credentials like:
Username and password
Biometrics (fingerprint, facial recognition)
Smart cards
Multi-factor authentication (MFA)
Goal: Ensure that the person or system is who they claim to be.
- Authorization
What it is: Granting or denying access to specific resources based on the authenticated identity.
How it’s done: Based on policies or access control lists (ACLs).
Example: A user may be authenticated to the network but only authorized to access a specific folder or database.
Goal: Control what an authenticated user is allowed to do.
- Accounting
What it is: Tracking and logging the activities of users and systems.
How it’s done: Through logs and audit trails.
Example: Recording login times, accessed resources, and changes made.
Goal: Provide traceability for security and compliance purposes.
AC (Alternating Current)
In AC, the voltage and current alternate between positive and negative values.
This creates a sine wave when visualized on a graph.
The frequency of this alternation is measured in Hertz (Hz).
In the United States, standard AC power is 60 Hz, meaning the current changes direction 60 times per second.
In many other countries, it’s 50 Hz
1. AC Powers Your Devices
Wall outlets provide AC power.
Computers, monitors, and other electronics are powered from this source.
- AC to DC Conversion
Most electronics (including computers) actually use Direct Current (DC) internally.
Power supplies (like the Power Supply Unit, PSU, in a PC) convert AC to DC.
This is part of what a PSU does: AC input → DC output (to components).
- Understanding Voltage
In the U.S., typical outlets provide 120 volts AC.
In many other countries, it’s 220–240 volts AC.
Knowing this helps you choose the right power supply or travel adapter.
ACL (Access Control List)
An Access Control List (ACL) is a list of rules that controls incoming and outgoing network traffic or user permissions. It defines what users, groups, or devices are allowed or denied access to specific resources.
Two Common Contexts for ACLs:
1. File System ACL (Permissions)
Used on files and folders.
Determines which users or groups can:
Read
Write
Execute
Delete
Common in Windows and Linux systems.
Example:
File: report.docx
ACL might say:
User1: Read, Write
User2: Read only
User3: No access
- Network ACL (Router/Firewall)
Used on routers, firewalls, and other network devices.
Controls network traffic based on:
IP addresses
Protocols (TCP, UDP)
Port numbers
Direction (inbound or outbound)
Example:
Rule: Deny all traffic from IP 192.168.1.100
Rule: Allow HTTP (port 80) traffic from any IP
ADF (Automatic Document Feeder)
An Automatic Document Feeder (ADF) is a mechanism that automatically feeds multiple sheets of paper into a scanner, copier, or fax machine, one at a time, without requiring manual input for each page.
AES (Advanced Encryption Standard)
Advanced Encryption Standard (AES) is a key concept under security, specifically related to data encryption. It’s important for understanding how data is kept safe—both on devices and across networks.
AES is a symmetric encryption algorithm used to protect data by converting it into an unreadable format, which can only be reversed (decrypted) with the correct key.
Key Characteristics of AES:
Feature Description
Type Symmetric key encryption (same key for encryption and decryption)
Block Size 128 bits
Key Sizes 128, 192, or 256 bits (more bits = stronger encryption)
Speed Fast and efficient for both hardware and software
Security Level Considered very secure and widely used in government, industry, and personal applications
AP (Access Point)
An Access Point (AP) is a device that allows wireless devices to connect to a wired network using Wi-Fi. It acts as a bridge between wired Ethernet and wireless clients (like laptops, smartphones, or tablets).
Types of Access Points:
1.) Standalone Access Point
A separate device connected to a switch or router via Ethernet.
Common in larger business networks.
2.) Wireless Router (with Built-in AP)
Most home routers include a built-in access point.
Combines routing, switching, and wireless access in one device.
APFS (Apple File System)
APFS stands for Apple File System. It is a modern file system developed by Apple, designed to replace HFS+ (Hierarchical File System Plus). It became the default for macOS starting with macOS High Sierra (10.13) and is used on macOS, iOS, iPadOS, watchOS, and tvOS.
APIPA (Automatic Private Internet Protocol Addressing)
APIPA is a feature in Windows and other operating systems that automatically assigns an IP address to a device when a DHCP server is unavailable and the device cannot obtain a valid IP address from the network.
How It Works:
A device is set to obtain an IP address automatically (via DHCP).
If no DHCP server responds, the device assigns itself an IP address from a reserved APIPA range:
169.254.0.1 to 169.254.255.254
The subnet mask is always:
255.255.0.0
The device can only communicate with other devices on the same local network that also have APIPA addresses.
Common Scenario:
A user complains they can’t access the internet. You check their IP and see 169.254.23.57. This means the computer couldn’t reach the DHCP server and is using APIPA—they can’t access anything beyond the local network.
APK (Android Package)
What is an Android Package (APK)?
An APK (Android Package Kit) is the file format used to distribute and install applications on Android devices.
Think of it like a .exe file on Windows or a .app file on macOS—it contains all the components needed to install and run an Android app.
Summary:
Term APK (Android Package Kit)
Purpose Contains everything needed to install an Android app
File Extension .apk
Used On Android devices
Install Methods Google Play, sideloading
A+ Relevance App management, security, and troubleshooting
Advanced RISC (Reduced Instruction Set Computer) Machine
Advanced RISC Machine, more commonly known as ARM, refers to a family of Reduced Instruction Set Computing (RISC) architectures developed by ARM Ltd. (originally Acorn RISC Machine). ARM processors are widely used in mobile devices, embedded systems, and increasingly in servers and desktops.
Key Features of ARM (Advanced RISC Machine):
RISC Architecture: Utilizes a simplified set of instructions, which enables faster execution and energy efficiency.
Low Power Consumption: Ideal for mobile devices and battery-powered electronics.
High Performance: Modern ARM cores offer high performance with multicore and out-of-order execution capabilities.
Scalability: Used in devices ranging from microcontrollers (e.g., ARM Cortex-M) to high-performance processors (e.g., ARM Cortex-A, Neoverse for servers).
Licensing Model: ARM Holdings designs the architecture and licenses it to other companies (e.g., Apple, Qualcomm, Samsung) who build their own chips.
ARP Address Resolution Protocol
What ARP Does:
When a device wants to communicate on a local network (like sending data to another computer), it needs the MAC address of the destination. However, it may only know the IP address. ARP helps by asking:
“Who has this IP address? Tell me your MAC address.”
How ARP Works:
The source device sends an ARP Request (a broadcast) asking for the MAC address associated with an IP.
The device with that IP replies with an ARP Reply, giving its MAC address.
The source device saves the IP-to-MAC mapping in its ARP cache to avoid repeating the process.
Why ARP Is Important in A+:
It’s part of the foundational knowledge for understanding TCP/IP networking.
It helps explain how devices talk within a local subnet.
It’s also relevant to troubleshooting connectivity issues.
Let me know if you want a diagram of ARP in action, or a quick quiz-style review.
