Enterprise IT Systems & Technology Glossary

Data Center

A data center is a physical facility where enterprise computing resources are housed, including servers, networking equipment, and cooling systems.

Server

A server is a computer that provides data, applications, or services to other systems or users over a network.

Bare Metal

Bare metal refers to running workloads directly on physical hardware without virtualization layers.

Rack

A rack is a cabinet that stores multiple servers and networking components in a data center.

Virtual Machine (VM)

A VM is a virtual computer created on top of physical hardware using a hypervisor. Each VM runs its own OS and applications.

Hypervisor

A hypervisor manages VMs on a physical server.

Types:

• Type 1 (Bare-metal) – runs directly on hardware (VMware ESXi, Hyper-V)
• Type 2 – runs inside an existing OS (VirtualBox)

Operating System (OS)

Software that manages hardware and provides system services.

Common enterprise OS:

• Linux (Ubuntu, RHEL)
• Windows Server
• UNIX (AIX, Solaris)

LAN (Local Area Network)

A Local Area Network connects computers within a building or office.

WAN (Wide Area Network)

A Wide Area Network connects multiple geographically distant LANs.

VLAN (Virtual LAN)

A Virtual LAN divides a physical network into multiple logical networks for isolation and security.

Subnet

A subnet breaks an IP network into smaller segments for efficient routing.

Switch

A device that connects devices within a LAN and forwards packets based on MAC addresses.

Router

Directs traffic between networks based on IP addressing.

Firewall

Controls traffic based on security rules to prevent unauthorized access.

DNS (Domain Name System)

Translates domain names into IP addresses.

Load Balancer

Distributes traffic across multiple servers to improve performance and availability.

Proxy

A device or service that acts as a gateway between user requests and backend servers.

CDN (Content Delivery Network)

A Content Delivery Network caches static content (images, videos, scripts) at geographically close edge locations to speed up delivery.

VPN (Virtual Private Network)

A Virtual Private Network encrypts network communication, allowing secure remote access.

Public Cloud

Infrastructure hosted by cloud providers like AWS, Azure, and GCP and shared between organizations.

Private Cloud

Cloud resources reserved for a single organization.

Hybrid Cloud

Mix of private and public cloud environments.

Multi-Cloud

Using more than one public cloud provider.

IaaS (Infrastructure as a Service)

Renting VMs, networks, and storage.

PaaS (Platform as a Service)

The cloud provider manages servers and runtime; you deploy applications.

SaaS (Software as a Service)

Complete applications offered online.

FaaS / Serverless

Code runs in response to events without managing servers.

FinOps

Financial operations discipline for optimizing cloud spending.

Cloud Governance

Policies and controls ensuring cloud deployments are secure, compliant, and cost-efficient.

CSPM (Cloud Security Posture Management)

Tools that continuously check for cloud misconfigurations.

Monolithic Architecture

All application features exist in one codebase and deployment.

Microservices

Application broken into independent services communicating over APIs.

SOA (Service-Oriented Architecture)

Early generation of service-based design using shared middleware (e.g., ESB).

N-Tier Architecture

Application split into layers:

• Presentation (UI)
• Logic
• Data

API (Application Programming Interface)

A defined interface that allows systems to communicate.

REST

Web API style based on HTTP verbs (GET, POST, PUT).

GraphQL

A query language where clients request only the data they need.

gRPC

High-performance binary RPC protocol for microservices.

Synchronous Communication

Client waits for the service to respond.

Asynchronous Messaging

Client sends a message to a queue without waiting.

Message Queue

Stores and routes asynchronous messages.

Event Bus

Broadcasts events to multiple subscribers.

RDBMS (Relational Database Management System)

Relational database using tables and SQL.

NoSQL

Non-relational databases for high-scale distributed workloads.

Types:

• Document (MongoDB)
• Key-Value (Redis)
• Graph (Neo4j)
• Columnar (Cassandra)

Data Warehouse

Central store optimized for analytics and reporting (Snowflake, Redshift).

Data Lake

Stores raw and structured data for large-scale analytics.

ETL (Extract, Transform, Load)

Extract → Transform → Load before data enters the warehouse.

ELT (Extract, Load, Transform)

Data loaded raw and transformed afterward.

Data Pipeline

Automated flow of data between systems.

Hadoop

Distributed batch processing framework for massive datasets.

Spark

Fast in-memory processing engine used for streaming, ML, and ETL.

OLAP (Online Analytical Processing)

Analytical querying of large aggregated datasets.

Business Intelligence (BI)

Dashboards, visualization, and enterprise reporting.

Authentication (AuthN)

Proves user identity (login, biometrics, tokens).

Authorization (AuthZ)

Determines what actions an authenticated user is allowed to perform.

IAM (Identity and Access Management)

Manages user identities and permissions across systems.

RBAC (Role-Based Access Control)

Users receive permissions based on assigned roles.

MFA (Multi-Factor Authentication)

Requires two or more authentication methods (e.g., password + OTP).

Encryption

Protects data using mathematical cryptography.

• At Rest: stored data
• In Transit: data moving over networks

Zero Trust

Security model assuming no user, device, or network is trusted by default.

GDPR

EU regulation on user privacy and data protection.

HIPAA

U.S. standard for healthcare data protection.

PCI-DSS

Standard for securing payment card data.

ISO 27001

International certification for information security management.

SDLC (Software Development Life Cycle)

Structured process for designing, building, testing, and deploying software.

Version Control

Manages source code changes.

CI (Continuous Integration)

Automatically builds and tests code when changes are committed.

CD (Continuous Deployment/Delivery)

Pushes validated code to production.

Artifact Repository

Stores compiled build outputs (container images, packages).

IaC (Infrastructure as Code)

Defines infrastructure using files rather than manual configuration.

Tools:

• Terraform
• CloudFormation
• ARM Templates

Configuration Management

Automates host configuration and upgrades.

Tools:

• Ansible
• Puppet
• Chef

Containers

Package applications and dependencies into consistent deployable units.

Container Orchestration

Manages container clusters, scaling, and health.

Standard tool: Kubernetes

Logs

System and application activity records, useful for debugging.

Metrics

Numeric time-series measures (CPU, latency, request counts).

Tracing

Tracks requests as they move across microservices.

Monitoring

Tools collecting logs, metrics, traces, and health data.

SIEM (Security Information & Event Management)

Aggregates security logs to detect threats.

NOC (Network Operations Center)

Responsible for system uptime monitoring.

SOC (Security Operations Center)

Focused on threat detection and incident response.

ITIL

Framework for managing IT services and processes.

TOGAF

Enterprise architecture framework for aligning business goals with technology systems.

COBIT

Framework for IT governance and compliance.

SLA (Service Level Agreement)

Defines uptime, performance, and service guarantees.

Change Management

Controls how production systems are modified to reduce risk.

Incident Management

Processes to restore services after outages.

CMDB (Configuration Management Database)

Documents infrastructure components and their relationships.