Popcorn

Popcorn is a learning kernel: a small operating-system core you can boot in an emulator, read line by line, and change without fighting a huge codebase. Version 0.6 adds real virtual memory (boot identity map plus per-task page tables), a physical frame allocator driven by the Multiboot2 memory map, and an IRQ keyboard queue so the shell stays responsive under timer preemption. After init, you get a simple text console while the PIT still feeds the scheduler—with guardrails so boot does not context-switch too early.

If you already know OS terms, see the operation map for boot flow and interrupts, or the source catalog for every core/ and pops/ file and how they link.