Relational Theory
Database normalization is the systematic process of structuring a relational schema to minimize d…
Infrastructure Notes
Server administration, databases, networking, and security reference materials for systems engineers.
Databases
Section titled “Databases”Every non-trivial system you build, operate, or debug depends on a database. Authentication token…
Sql Fundamentals
Advanced SQL notes covering key definitions, core concepts, worked examples, and practice questio…
Indexing Optimization
Without an index, finding a specific row in a table of rows requires a full sequential scan, Whic…
Transactions
PostgreSQL uses a multi-level locking system that operates at different granularities. Understand…
Nosql
NoSQL databases and the CAP theorem.
Database Design
Normalization eliminates redundancy and update anomalies, but there is a point of diminishing Ret…
Licensing
Section titled “Licensing”Introduction to Linux operating system fundamentals.
Cli Fundamentals
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File Systems
Every file and directory on a Linux system carries a set of permission bits that control which us…
Process Management
The cron daemon () is a time-based job scheduler that runs commands at specified times and Interv…
Networking
The traditional DNS resolver configuration file:
Systemd
is the central logging daemon in systemd-based systems. It collects log messages From multiple so…
Security
Linux security is fundamentally built on the user and group model. Every process runs under a Spe…
Package Management
A Linux package is an archive containing compiled software, configuration files, metadata (versio…
Lvm And Disk Partitioning
Linux exposes storage devices as block device files under . Block devices support random Access b…
Machine Learning
Section titled “Machine Learning”Networking
Section titled “Networking”Every system you operate, deploy, or debug depends on networking. A container cannot reach its Da…
Osi Model
Network reference models provide a structured vocabulary for discussing protocol behavior. They a…
Ip Addressing
IP addressing is the mechanism by which hosts are identified and located on an IP network. Every …
Tcp Udp
The transport layer provides end-to-end communication services between processes on different hos…
Dns
DNS infrastructure is the backbone of Internet naming. Beyond the recursive resolution process Co…
Http Https
HTTP/2 (RFC 9113) and HTTP/3 (RFC 9114) are the modern versions of the Hypertext Transfer Protoco…
Tls
This document goes deeper into TLS internals than the TLS fundamentals document, covering the rec…
Network Tools
Network troubleshooting is a systematic process of isolating and identifying the root cause of Co…
Layer2
Layer 2 networking and Ethernet fundamentals.
Wireless
Wireless networking fundamentals and protocols.
Email And App Protocols
Electronic mail and application-layer protocols form the backbone of human communication over the…
Bgp And Routing Protocols
Routing is the process of selecting a path across a network for traffic to travel from a source t…
Practice Networking
12 practice problems covering fundamental networking concepts: OSI model, TCP/IP, DNS, HTTP, subn…
Security
Section titled “Security”Information security is not a feature you bolt on after the fact. It is a property of a system th…
Security Fundamentals
The CIA triad is the foundational model for information security. Every security control, Vulnera…
Cryptography
Cryptography is the mathematical science of securing communication and data. It is not a security…
Authentication
Authentication and authorization fundamentals.
Web Security
REST APIs are stateless by design: each request must contain all information needed for Authentic…
Network Security
A firewall is a network security device or software that monitors and filters incoming and outgoi…
Incident Response
The chain of custody is a documented record of every person who handled evidence, when, where, an…
Cloud Security
Cloud security is governed by a shared responsibility model. The division of responsibility betwe…
Os Security
SSH is the primary remote administration protocol on Linux. Default configuratio
Malware Analysis
Malware classification is the foundational step in any analysis workflow. Understanding the categ…
Pentesting And Attacks
Penetration testing is an authorized, simulated attack against a system, network, or Application …
Truenas
Section titled “Truenas”Reference for deploying and managing TrueNAS (CORE and SCALE), covering ZFS pool design, dataset …
Zfs
ZFS is not a traditional filesystem. It is a combined volume manager and filesys
Sharing And Permissions
Server Message Block (SMB) is the primary file sharing protocol for Windows environments. TrueNAS…
Backup And Replication
The 3-2-1 rule is the minimum standard for data protection:
Apps And Services
TrueNAS SCALE uses a Kubernetes-based application framework. Apps run as Helm charts deployed int…
Monitoring And Alerting
The TrueNAS dashboard provides a real-time overview of system health:
Performance Tuning
The Adaptive Replacement Cache (ARC) is ZFS
Setup
For a homelab NAS running TrueNAS SCALE, CPU choice depends on the workload:
Zfs Encryption
ZFS native encryption is a dataset-level encryption mechanism integrated into the ZFS storage sta…
Tuning
Section titled “Tuning”Hardware tuning reference covering undervolting, overclocking, memory tuning, stress testing Meth…
Cpu Tuning
A modern CPU is a superscalar, out-of-order, speculative execution engine. Understanding these Co…
Memory Tuning
DDR5 represents a fundamental shift in memory architecture. The comparison is not merely about sp…
Gpu Tuning
NVIDIA GPUs are organized into Streaming Multiprocessors (SMs), each containing a set of CUDA cor…
Storage Tuning
| Technology | Sequential Read | Sequential Write | 4K Random Read (IOPS) | 4K Random Write (IOPS…
Cooling Systems
Every cooling solution relies on three mechanisms of heat transfer:
Stress Testing
Stress testing serves three purposes for a systems engineer:
Psu And Bios Guide
A power supply unit (PSU) converts alternating current (AC) from the wall outlet into the direct …
Undervolting And Overclocking
Undervolting is the process of reducing the operating voltage (Vcore for CPUs and Vddc for GPUs) …
How to Use These Notes
Section titled “How to Use These Notes”- Start with the fundamentals — build a solid foundation before moving to advanced topics
- Work through examples — follow along with the worked examples to build intuition
- Test yourself — use the practice problems and flashcards to check your understanding
- Review regularly — spaced repetition helps retain what you have learned