IPC

docs/README.md

@@ -32,9 +32,12 @@ rather than restate it. Roughly in the order things happen at runtime:
    the VMM, exposed as a `std.mem.Allocator` so std containers work — dynamic
    allocation for the kernel.
 10. **[scheduling.md](scheduling.md) — the scheduler.** Fixed-priority preemptive
-    multitasking: kernel threads, the context switch, and O(1) priority selection —
-    the leap to a running system.
-11. **[halting.md](halting.md) — halting.** Why a kernel can't just "exit", and
+    multitasking: kernel threads, the context switch, O(1) priority selection, and
+    blocking (sleep, wait queues) — the leap to a running system.
+11. **[ipc.md](ipc.md) — inter-process communication.** Bounded blocking
+    message-passing channels — the backbone the microkernel's isolated servers will
+    talk over.
+12. **[halting.md](halting.md) — halting.** Why a kernel can't just "exit", and
     how `while (true) hlt` parks the CPU safely once there's nothing left to do.
 
 Start with the north star:
@@ -65,8 +68,9 @@ its **descriptor tables** so CPU faults are caught ([interrupts.md](interrupts.m
 builds its own **page tables** and switches onto them ([paging.md](paging.md)),
 brings up the **heap** for dynamic allocation ([heap.md](heap.md)), starts the
 **scheduler** ([scheduling.md](scheduling.md)) and the **timer** that preempts it
-([device-interrupts.md](device-interrupts.md)), runs — its CPU-specific bits behind
-the [arch](arch.md) boundary — and when idle, or on a panic, it **halts**
+([device-interrupts.md](device-interrupts.md)) — with tasks blocking, sleeping and
+passing messages over **[IPC](ipc.md)** channels — runs, its CPU-specific bits
+behind the [arch](arch.md) boundary, and when idle, or on a panic, it **halts**
 ([halting.md](halting.md)).
 
 ## Source map
@@ -78,7 +82,8 @@ the [arch](arch.md) boundary — and when idle, or on a panic, it **halts**
 | Shared loader↔kernel contract (`BootInfo`, `Framebuffer`, `MemoryMap`, ABI) | `src/root.zig` |
 | Physical frame allocator | `src/pmm.zig` |
 | Kernel heap (`std.mem.Allocator`) | `src/heap.zig` |
-| Scheduler (fixed-priority preemptive) | `src/sched.zig` |
+| Scheduler (fixed-priority preemptive; blocking, wait queues) | `src/sched.zig` |
+| IPC channels (message passing) | `src/ipc.zig` |
 | Framebuffer text console (mirrors to serial) | `src/console.zig` |
 | In-kernel test cases | `src/tests.zig` |
 | Arch-specific kernel code (`halt`, GDT/IDT/TSS, exception + interrupt stubs, page tables, APIC/timer, serial, linker script) | `src/arch/x86_64/` |