YaliOS

The first bootable YaliOS kernel: a minimal no_std Rust x86_64 kernel that boots through the bootloader crate and runs in QEMU BIOS mode.

Prerequisites

• Rustup with the nightly toolchain
• bootimage: cargo install bootimage
• QEMU with qemu-system-x86_64 on PATH

On Windows, install QEMU separately and add its installation directory to PATH before running the commands below.

Build and run

cargo bootimage
cargo bootimage run

The kernel writes YaliOS 0.1 and Kernel online to VGA text memory. The same banner is sent to COM1, so cargo bootimage run displays it in the QEMU terminal and exits only when QEMU is closed.

The generated disk image is placed under target\x86_64-...\debug\bootimage-yali_os.bin.

After boot, the serial console shows a yali> prompt. Input can come from COM1 (the QEMU serial terminal) or a directly attached PS/2 keyboard. The shell supports help, about, version, clear, echo <text>, pwd, ls, cd, mkdir, touch, cat, write <path> <text>, rm, mv, and cp. ls accepts -a, -l, and combined -la/-al, plus backspace and Enter editing in a fixed 128-byte command buffer.

Install and persistence test

Run build-install-test.cmd from Windows. It builds the boot image, creates a fresh 64 MiB image under target\installed-vhd\yali-os.img, installs the bootloader/kernel image at LBA 0, and runs two QEMU boots. The first boot explicitly formats the newly created image with format /dev/yali-test and writes a file; the second boot mounts the same image and reads it back.

To launch that installed image interactively afterward, run run-shell.cmd. The workflow only creates and overwrites the exact image inside target and does not touch physical disks or Windows boot configuration.

YaliFS

YaliFS is a small fixed-layout filesystem in the installed test disk. It has a root directory, nested directories, and text files. Paths may be absolute or relative and support . and .. where applicable. It is limited to 32 nodes, 24-byte names, and 256-byte file contents. Its metadata begins at LBA 2048, leaving the boot image at the start of the disk. The format uses a superblock, two metadata sectors, and one fixed data sector per node; it has no allocator, permissions, timestamps, journaling, or crash recovery.

Accounts and permissions

An explicit setup-users flow creates root (UID 0) and user (UID 1000), requiring passwords of at least eight printable characters. Passwords are stored as salted SHA-256 hashes, never plaintext. The filesystem persists owners and Unix-style mode bits; /home/user is created as a user-owned 0700 directory. login, whoami, id, and root-only chmod are available.

This is not yet a secure Linux-style process boundary. The shell still runs in kernel mode, and there are no ring-3 processes, per-process address spaces, or capability isolation. Permission checks are kernel filesystem checks for the authenticated shell credential only; YaliOS does not claim full user isolation until process support exists.

What exists in this first version

• BIOS boot via bootloader 0.9
• Rust no_std / no_main kernel entry point
• VGA text-mode output
• COM1 serial output for headless QEMU runs
• Polling input from COM1 and the PS/2 keyboard (no keyboard IRQs)
• Small fixed-buffer command shell
• Fixed-size persistent YaliFS with basic path and file operations

Hardware discovery milestone

At boot, YaliOS now reports the CPU vendor/basic features, validates the bootloader-provided memory map, validates an ACPI RSDP checksum when the BIOS exposes one, and enumerates PCI configuration space. PCI output distinguishes detected devices, initialized drivers, and usable drivers. The QEMU IDE PIO path is marked usable only after a real read/write test on the YaliFS sector; other devices are only detected. This is discovery, not general hardware support: there is no PCI interrupt routing, allocator, USB, network, framebuffer, or generic device-driver framework yet.

• Panic handler that reports a kernel panic and halts
• CPU halt loop to avoid spinning while idle