Operating Systems
How one machine runs your program. Eight guides in the full TechForge style — theory, diagrams, code, interview questions and a quiz each. All live now.
What is an operating system?
An operating system (OS) is the software layer between your programs and the raw hardware. Your code never talks to the CPU, RAM or disk directly — it asks the OS, which arbitrates those resources among every running program and hands each one a clean, safe abstraction to work with.
An OS manages four things: the CPU (deciding who runs, when), memory (allocation and protection), storage (files and directories), and I/O devices — all while giving each program the illusion that it owns the whole machine.
That illusion is the whole trick. Processes think they have all of memory (virtual memory), all of the CPU (scheduling), and private files (the filesystem). Master how the OS creates those illusions and the rest of computer science — databases, containers, networking, system design — stops feeling like magic. It’s also the single richest source of interview questions.
Eight guides, built to be read top to bottom — each one assumes the last. Click any step to jump in.