Tech Docs

groupdel removes a local Linux group from the system account database. Linux Command #41 follows Linux Command #40 – groupadd. The earlier lesson created local groups; this lesson covers removing a group safely, checking for primary-group dependencies, verifying deletion, and identifying files that may still retain the deleted numeric GID. 1. Basic syntax The Debian…

Python dataclasses reduce repetitive class boilerplate by generating common methods from a compact set of annotated fields. OSPython.024 continues the Open-Source Python sequence after OSPython.023: Type Hints and Annotations Basics. Dataclasses combine several earlier Python concepts: classes, decorators, type annotations, defaults, comparison behavior, and object representation. 1. What a dataclass is A dataclass is a…

IP gets packets between hosts. TCP and UDP determine how applications exchange data between processes on those hosts. OSNTC.014 continues the Open Source Networking Technician Certification after OSNTC.013: Router Basics. Routers forward IP packets between networks; transport protocols add application-facing communication through port numbers, sequencing, acknowledgements, flow behavior, and datagram delivery. The transport-layer model application…

Firmware engineering begins where software meets silicon: the processor executes instructions, memory maps define what addresses mean, registers expose hardware state, and interrupts let external events redirect execution. This is OSFEC.001, the first lesson in the Open Source Firmware Engineer Certification track. It builds on OSFTC.001: Firmware Images, Safe Flashing, Bootloaders, and Recovery Basics and…

Firmware service is controlled change on hardware that can become unusable if the wrong image, wrong target, interrupted write, incompatible configuration, or failed recovery path is handled badly. This is OSFTC.001, the first lesson in the Open Source Firmware Technician Certification track. It establishes the field workflow for identifying firmware, backing up what matters, validating…

A fiber link is not engineered by asking whether light reaches the far end. It is engineered by proving that the receiver gets enough optical power under worst-case conditions—without being overloaded—and that enough margin remains for aging, contamination, repair, measurement uncertainty, and real-world variation. This is OSFOEC.001, the first lesson in the Open Source Fiber…

Fiber optic work is precision work: eye protection, glass-scrap control, optical-source awareness, bend-limit discipline, and clean connector endfaces are fundamental safety and reliability requirements. This is OSFOTC.001, the first lesson in the Open Source Fiber Optics Technician Certification track. It establishes the habits that every later lesson depends on: safe handling, connector discipline, inspection, cleaning,…

Data-center reliability is not created by buying “extra equipment.” It is created by making sure the critical load can survive the exact failures and maintenance states the business requires. This is OSDCEC.001, the first lesson in the Open Source Data Center Engineer Certification track. It builds directly on OSDCTC.001: Data Center Floor Fundamentals and moves…