Overview

The init module is the kernel's sequential startup orchestrator. It is entered once, runs each subsystem check in order, prints a status line for each step, then hands off to the scheduler — at which point it never runs again.

The single entry point is init::check::init(m2_ptr: u32), called from main.rs with the Multiboot2 info pointer left in a register by the bootloader.

Boot Sequence

main(m2_ptr)
  └── init::check::init(m2_ptr)

Steps execute in this exact order:

#	Call	Module	Description
1	`vga::init_writer()`	`video/vga.rs`	Create the VGA text `Writer` at `0xB8000`
2	`clear_screen!()`	macro	Blank the 80×25 text buffer
3	`cpu::check()`	`init/cpu.rs`	Enable SSE (CR4/CR0), set up SYSCALL/SYSRET MSRs
4	`idt::idt_isrs_init()`	`init/idt.rs`	Install ISRs, reload GDT, init TSS, load IDT
5	`mouse::init()`	`input/mouse.rs`	Enable PS/2 aux port and IRQ12
6	`parser::parse_info(m2_ptr, ...)`	`init/parser.rs`	Parse Multiboot2 tags; fill `FRAMEBUFFER_PTR`
7	`heap::pmm_heap_init()`	`init/heap.rs`	Init kernel linked-list heap; run smoke test
8	`video::print_result(...)`	`init/video.rs`	Call `init_video(fb)` to set `VIDEO_MODE`
9	`fs::floppy_check_init()`	`init/fs.rs`	Probe FAT12 floppy; set cwd to `/`
10	`fs::vfs_init()`	`init/fs.rs`	Mount `/`, `/mnt/fat`, `/mnt/iso` (if CD present)
11	`color::color_demo()`	`init/color.rs`	Print 16-color swatch to console
12	`ascii::ascii_art()`	`init/ascii.rs`	Print kernel splash text
13	`process::init_processes()`	`init/process.rs`	Save CR3, init userland heap, create initial tasks
14	`pit::pic_pit_init()`	`init/pit.rs`	Remap 8259A PIC; start PIT at 100 Hz; `sti`

Step 14 (sti) is the point of no return — from here the PIT fires every 10 ms and the scheduler takes over. init never runs again.

Global State Set During Init

Symbol	Type	Set by step	Description
`FRAMEBUFFER_PTR`	`boot::FramebufferTag`	6	VESA framebuffer address, pitch, dimensions, bpp
`VIDEO_MODE`	`Option<VideoMode>`	8	Active video path (Framebuffer or TextMode)
`SYSTEM_CONFIG`	`Mutex<SystemConfig>`	9	hostname, user, cwd, version, IP, MAC
`KERNEL_CR3`	`u64`	13	Boot-time page table snapshot for process cloning
Userland heap P2[6/7]	page table	13	`0xC00_000–0xFFF_FFF` mapped USER+WRITE
`SCHEDULER`	`Mutex<Scheduler>`	13	Initial process slots populated

Module Table

File	Purpose
`check.rs`	Entry point `init()`, `FRAMEBUFFER_PTR` global
`boot.rs`	Multiboot2 tag structs, `parse_multiboot2_info`
`parser.rs`	Thin `Result`-returning wrapper around `boot::parse_multiboot2_info`
`cpu.rs`	SSE enable, SYSCALL/SYSRET MSR setup
`idt.rs`	GDT reload, TSS init, IDT load
`pit.rs`	8259A PIC remap, PIT 100 Hz init
`heap.rs`	Kernel heap init + smoke test
`fs.rs`	Floppy probe, VFS mount table init
`video.rs`	`init_video()`, optional VESA P1 mapping
`process.rs`	Initial task creation (kmain, init_rc, clock, shell)
`config.rs`	`SYSTEM_CONFIG` global, `get_prompt()`
`font.rs`	PSF1/PSF2 font parser, `PSF_FONT` static, glyph renderer
`ascii.rs`	Splash screen text
`color.rs`	16-color palette swatch