simple os: on the x86/32 bit mode platform.

• using x86 protected mode.
• process switch.
• implement fork/exec/wait.
• support vga graphic mode, in protected mode switch to graphic mode and switch back to text mode.
• kernel loader can load more than 1M size kernel (using Unreal mode).
• ipc.
• ramdisk.

demo video:

boot loader loads the kernel loader (kernel_loader/kloaderp.bin) to 0x9000:0x0100.

in kernel loader, init c runtime, then use c code (16 bit) read elf kerenl (in Unreal mode) to memory address 0x300000+0x28*16 (by bios 0x13), then enter protected mode.

in protected mode, copy the the p_kernel.elf (c code, in the state, only can use stack variable) follow the elf header information (Program Headers:). then jump to the kernel address (elf entry point address).

kloaderp.bin load p_kernel.elf to 0x300000+0x28*16

than copy p_kernel.elf by elf information to absolute address 0x100000. kernel load address depends k.ld (. = 0x100000), current is 0x100000. p_kernel.elf entry pointer is 0x100000.

ramdisk filesystem is romfs. it is megered to p_kernel.elf.

tty design: 0, 1, 2 text mode alt+f1, alt+f2, alt+f3 The 3rd tty is graphic mode (alt+f6) now can switch graphic/text mode tty.

the url show some pictures and a vidoe demo (in real pc). (http://descent-incoming.blogspot.tw/2013/02/x86-1m-kernel.html)

make test floppy image boot.bin is boot loader c-bootloader/mkimg.sh -b boot.bin -d boot.img

copy kernel loader and kernel to floppy image ./script/cp2img.sh

modify REAL_PC macro kernel_loader/protected_code.c if only in emulator, comment #define REAL_PC

compile/test: qemu: make

real pc: make REAL_PC=1

qemu cmd: qemu-system-i386 -fda boot.img --nographic # ctrl+a x to exit qemu-system-i386 -fda boot.img --display sdl qemu-system-i386 -fda boot.img --display curses # esc + 1, esc + 2 q enter to exit ref: http://stackoverflow.com/questions/14165158/how-to-switch-to-qemu-monitor-console-when-running-with-curses qemu-system-i386 -fda boot.img

bochs cmd: bochs 1.6.8 configure file x86.bxrc for bochs debugger x86-gdb.bxrc for gdb bochs -f x86.bxrc