Every operating system concept in one video…

TL;DR

A fast walkthrough of every core OS concept — from bootloader to shutdown — explaining how memory, processes, and hardware work together.

Key Points

• 1.The boot process moves through firmware, bootloader, and kernel in strict sequence. UEFI/BIOS finds the disk, hands off to a bootloader (GRUB on Linux, Bootmgr on Windows), which loads the kernel into RAM with full ring-zero hardware privileges.
• 2.Virtual memory is a deliberate lie enforced by the MMU and page tables. Each process gets its own virtual address space mapped to physical RAM in 4KB pages; a page fault triggers the kernel to load missing pages from disk transparently.
• 3.Files are stored as index nodes (inodes) that hold metadata and disk pointers — not filenames. Filenames live in directories, which map names to inode numbers, enabling hard links; journaling in modern filesystems (ext4, NTFS, APFS) prevents corruption on sudden power loss.
• 4.Hardware communicates via interrupts, not polling — a keypress or Wi-Fi packet fires an electrical signal that yanks the CPU into a kernel interrupt handler instantly. Drivers run in ring-zero kernel mode, meaning one bad driver (e.g., the 2024 CrowdStrike incident) can crash the entire OS.
• 5.Processes, threads, scheduling, and IPC are how the OS juggles hundreds of programs on eight cores. Linux's EEVDF scheduler allocates CPU time fairly; threads share memory but risk race conditions; IPC tools like pipes (invented 1973) and sockets let separate processes communicate safely.