Computer Memory, Storage, and Cloud Computing: Key Concepts and Technologies

Dual-Channel Memory

Two memory modules work in parallel, doubling bandwidth (128-bit total).

Virtual Memory

Disk storage used when RAM is full; slower but expands usable memory.

RAM (Volatile)

Data lost when power is removed.

ROM (Nonvolatile)

Read-only firmware storage; retains data without power.

Cache Memory

Fast, small memory close to CPU; most volatile.

Pagefile / Swap Space

Portion of drive used as 'overflow' RAM.

ECC Memory

Error-Correcting Code RAM; detects and corrects bit errors.

SO-DIMM

Small Outline DIMM; laptop memory form factor.

Parity Bit Memory

Detects but cannot correct errors.

IaaS (Infrastructure as a Service)

Virtualized compute, storage, and networking (e.g., AWS EC2).

PaaS (Platform as a Service)

Dev environment for applications (e.g., Azure App Services).

SaaS (Software as a Service)

Cloud-hosted applications (e.g., Gmail, Salesforce).

Private Cloud

Dedicated resources for one organization.

Public Cloud

Shared multi-tenant infrastructure.

Hybrid Cloud

Mix of public and private clouds.

Community Cloud

Shared among organizations with common goals.

High Availability

System designed for minimal downtime.

Rapid Elasticity

Automatic scaling up/down of resources.

Measured/Metered Service

Pay only for resources used.

GSM

Global System for Mobile Communications; uses SIM card.

CDMA

Code Division Multiple Access; no SIM, provisioned by carrier.

LTE (4G)

Long Term Evolution; up to ~100 Mbps, SIM required.

5G

Latest generation; ultra-low latency and gigabit speeds.

Hotspot

Device shares cellular data as Wi-Fi network.

Tethering

Share connection via USB or Bluetooth.

SIM Card

Stores subscriber identity and network credentials.

IMSI

International Mobile Subscriber Identity stored on SIM.

IMEI

Unique device identifier (hardware ID).

Airplane Mode

Disables all radios (cellular, Wi-Fi, Bluetooth).

Toner Vacuum

Specialized vacuum for removing toner safely.

Compressed Air

Never use on laser printers; spreads toner particles.

Corona Wire

Transfers charge to drum; must be kept clean.

Fuser Assembly

Melts toner onto paper; can cause burns if touched.

Drum Cleaning Blade

Removes residual toner during print cycle.

Calibration

Aligns color output and print heads.

Ghosting

Repeating faded image; caused by worn drum or fuser.

Streaks or Lines

Dirty corona wire or roller.

Paper Jam Prevention

Clean rollers and use correct paper weight.

IoT (Internet of Things)

Consumer-grade automation: smart thermostats, cameras, appliances.

SCADA (Supervisory Control and Data Acquisition)

Industrial control systems for factories, pipelines, utilities.

IoT Focus

Convenience and remote monitoring via cloud apps.

SCADA Focus

Process automation, safety, and industrial reliability.

IoT Connectivity

Wi-Fi, Bluetooth, Zigbee, Z-Wave, cellular.

SCADA Connectivity

Industrial Ethernet, serial, private networks.

IoT Example

Smart light bulbs.

SCADA Example

Water treatment or power grid control system.

Most Volatile

Cache / Registers → Lost instantly on power loss.

RAM

Lost on shutdown.

Flash Storage

Retains data (nonvolatile).

SSD / HDD

Permanent until erased.

Optical Media (CD/DVD)

Long-term nonvolatile storage.

Volatile Storage

Requires power to retain data (RAM, cache).

Nonvolatile Storage

Retains data without power (HDD, SSD, Flash, Optical).

certmgr.msc

Opens the Certificate Manager console to view, import, and manage security certificates on Windows.

lusrmgr.msc

Opens Local Users and Groups for managing local user accounts and group memberships.

GPT (GUID Partition Table)

Modern partition style that supports 128 partitions and drives larger than 2 TB; replaces MBR.

NTFS

Default Windows file system that supports file permissions, encryption, and large file sizes.

apt

Command for installing and managing packages on Debian-based Linux systems.

dnf

Command for installing and managing packages on Red Hat-based Linux systems (replaces yum).

chkdsk

Command that checks disk integrity and repairs file-system or sector errors.

WPA2 4-Way Handshake

Authentication process between a client and access point that verifies credentials and exchanges encryption keys.

Rogue antivirus

Fake antivirus software that mimics legitimate alerts to trick users into installing malware.

Data-at-rest encryption

Encrypts data stored on physical media such as HDDs, SSDs, and USB drives.

Data-in-transit encryption

Protects data moving across networks using TLS/SSL or VPNs.

Phishing

A social-engineering attack that tricks users into revealing credentials or downloading malware.

PCI DSS

Security standard for handling credit-card data and preventing payment fraud.

PHI

Protected Health Information governed by HIPAA regulations.

PII

Personally Identifiable Information such as name, address, SSN, or date of birth.

NIST compliance

U.S. government framework for cybersecurity risk management and best practices.

EULA

End-User License Agreement outlining terms and limitations of software use.

Safe Mode

Boots Windows using only essential drivers to isolate startup problems or malware.

msconfig

Tool to manage startup items and boot configurations for troubleshooting.

regedit

Registry Editor — allows manual edits to system configuration and malware removal.

WinPE

Minimal Windows environment used for system recovery and offline malware repair.

Overheating symptoms

Random shutdowns, reboots, or freezing due to poor cooling or dust buildup.

System instability causes

Failing CPU, overheating, or malware from firewall misconfiguration.

Purpose of the change

Describes the business justification and benefits for performing a system change.

Scope of the change

Outlines what systems, users, and timelines are affected by the change.

Proper documentation

Ensures customers understand timelines, procedures, and expectations for support.

Rotation lock

Prevents screen from auto-rotating between portrait and landscape modes.

.apk file

Android app installer file; considered untrusted on Apple devices.

App Store (macOS)

Used to download and check for system and app updates on Apple computers.

Gmail (Workspace)

Cloud-based enterprise email platform managed through Google Workspace.