OSDev.org

• x86_64
• 2MB pages
• Scheduler (kernel and user space)
• Syscalls
• Blocking calls e.g. window_get_message (task WAIT state)
• Drivers: mouse, keyboard, vesa, ata, fat 12/16/32
• Double buffered vesa graphics
• GUI (window, button, label, image) in users space

#include <klika_os.h>
#include <windows.h>

#define MSG_USER_WIN (WINDOW_USER_MESSAGE + 1)

int main() {
	message_t msg;
	window_t *window = window_create(100, 100, 300, 300, "Simple Application", MSG_USER_WIN);

	while(window_get_message(window, &msg)) { 
		window_dispatch(window, &msg);
	}
	return 0;
}

The first reserved cluster, FAT[0], contains the BPB_Media byte value in its low 8 bits, and all other bits are set to 1. For example, if the BPB_Media value is 0xF8, for FAT12 FAT[0] = 0x0FF8, for FAT16 FAT[0] = 0xFFF8, and for FAT32 FAT[0] = 0x0FFFFFF8. The second reserved cluster, FAT[1], is set by FORMAT to the EOC mark. On FAT12 volumes, it is not used and is simply always contains an EOC mark. For FAT16 and FAT32, the file system driver may use the high two bits of the FAT[1] entry for dirty volume flags (all other bits, are always left set to 1). Note that the bit location is different for FAT16 and FAT32, because they are the high 2 bits of the entry.