Boink Kernel Project

The Boink Kernel Project aims to provide a fairly usable abstraction for every layer between bare metal and user. It provides the following:

• filesystem (GLFS)
• bootloader (Boink Interactive Bootloader)
• kernel (BoinkOS)
• syscall interface
• custom libc

Two novel ideas have been implemented as part of this kernel —

• Kernel Scratchpad
  provides 16kb of "scratchpad" space for the kernel to use — avoids page management where it may not be needed
• Panic Diagnostic Shell
  provides a way to easily debug programs when a panic state is entered

Several OSDev milestones were accomplished in this project —

• custom 32-bit protected mode bootloader with VESA graphics
• paging and frame allocation
• syscalls + userland mode (ring3) context switching
• ELF binary loading and execution
• basic shell with file viewing, image viewing, and app execution
• interrupt handling with IRQs, ISRs, PIT, and keyboard input
• simple framebuffer-based graphics output
• GLFS — a simple loadable filesystem baked into the boot process

Other milestones were also achieved —

• less-inspired terminal pager with search function
• bitmap image viewer

Screenshots from development

First Steps — printing to the screen in VGA text mode



GLFS disk reads



VGA framebuffer graphics



Less-inspired Text Pager



Panic diagnostic shell



Boink Interactive Bootloader



Bitmap Image Viewer



ring3 context switching



Custom libc with basic I/O support

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GLFS Project

good little file system (affectionately good luck file system)

GLFS intends to be an insanely simple filesystem for use in hobby projects. GLFS is used by the Boink Interactive Bootloader to load the system into memory.

GLFS Structure Overview

	[sector 0] GLFS SUPERBLOCK
	----------
	- magic GLFS+version identifier

	[sector 1+] DIRECTORY TABLE
	-----------
	     [entry 0] filename: string
	               start sector: int
		       size: int (bytes)

	     [entry 1] filename: string
	               start sector: int
		       size: int (bytes)
	     (...)
     
	[end of table marker]
	----------
	[file data]
	(...)
	

[0] Superblock Overview

• size: 512b
• contents:
  • bytes 0..7: GLFSv0\n (7 bytes+newline)
  • bytes 7..511: reserved

[sector 1+] Directory Table Overview

• each 40-byte directory entry contains:
  • 32 byte filename
  • 4 byte (uint32) start sector (offset from sector 0)
  • 4 byte (uint32) file size in bytes
• end of table is marked with b'__END__' (8 bytes)

from GLFSv0 Spec

A full suite of GLFS tools is available here.

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Available Code

• BoinkOS
  main kernel code
  get the code>
• Boink Interactive Bootloader
  bootloader
  get the code>
• Kernel Template
  sample kernel template, loadable by Boink Interactive Bootloader
  get the code>
• Boink C Standard Library
  minimal C Standard Library implemntation for BoinkOS.
  get the code>
  or get the reference>
• BoinkOS Userland Template
  userland program template for BoinkOS — compiles both .elf and .bin files
  get the code>
• GLFS Tools
  tools for creation and editing of GLFS formatted disk images
  get the code>