I already have a heap allocator implemented. The bad news is, it's implemented in a unit. The system unit defines heap functions as external (I made my system unit by cutting down Win32 one, but I use ELF as executable format. Nutz, isn't it?), the only way I can think of is to reimplement mine as a library. But my OS doesn't have dynamic loading ability yet. It's like a chicken and egg problem!