[Verse 1] Down in the silicon valley of your machine Two worlds divided by a boundary unseen User space above where applications play Kernel space below where the system holds sway Ring three to ring zero, privilege descends Protected mode ensures where each process ends [Chorus] Kernel space, user space, separated by design System calls bridge the gap across the privilege line Ring zero power, ring three confined Hardware enforcement keeps the boundaries defined User space thinks, kernel space acts Protection rings keep the system facts intact [Verse 2] When your program needs to read a file today It cannot touch the hardware, there's a safer way A system call transitions through the gate From user mode to kernel, privilege escalates The kernel checks permissions, validates the request Then returns to user space when the job's addressed [Chorus] Kernel space, user space, separated by design System calls bridge the gap across the privilege line Ring zero power, ring three confined Hardware enforcement keeps the boundaries defined User space thinks, kernel space acts Protection rings keep the system facts intact [Bridge] Why do drivers live in kernel land? Direct hardware access, they need command Interrupt handlers can't wait in line They need ring zero privilege, by design Memory management, process scheduling too Only kernel space can see the system through [Verse 3] Virtual memory maps what user programs see But physical addresses, only kernel's got the key Page tables translate in the kernel's domain While user space believes its memory's the same Context switches happen in the kernel's core Saving state and loading what comes before [Chorus] Kernel space, user space, separated by design System calls bridge the gap across the privilege line Ring zero power, ring three confined Hardware enforcement keeps the boundaries defined User space thinks, kernel space acts Protection rings keep the system facts intact [Outro] From application down to silicon base Remember the boundary, remember the space User above and kernel below That's how secure systems grow
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