Pillar 1 · Operating Systems

Operating Systems

How one machine runs your program. Eight guides are being written in the full TechForge style — diagrams, quizzes, interview questions — and land here topic by topic.

The roadmap

Processes & Threads

What a process really is, threads vs processes, context switching, and the cost of each.

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CPU Scheduling

FCFS, round-robin, priority and multilevel queues — how the OS decides who runs next.

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Memory Management

Virtual memory, paging, page faults, TLBs — the illusion every process lives alone.

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Concurrency & Synchronization

Race conditions, mutexes, semaphores, and why your tests pass but prod deadlocks.

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Deadlocks

The four conditions, prevention vs avoidance vs detection, and the banker's algorithm.

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Filesystems

Inodes, journaling, and what actually happens on open(), write(), fsync().

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I/O & Interrupts

Polling vs interrupts vs DMA, blocking vs non-blocking I/O, and where epoll fits.

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Boot to Shell

From power button to prompt — BIOS/UEFI, kernel init, and the process tree.

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