pOS - portable Operating System
05/06/03

Memory management in pOS kernel, version 0.0.1

The memory management in this first kernel release
is quite simple but very efficent by having a small
overhead. The memory is allocated in dynamically sized
blocks that have the following structure:

        ----------------- Offset
        | PID of Owner  | 0x00
        -----------------
        | Size in bytes | 0x01
        -----------------
        |               | 0x03 (0x05)
        | Memory space  |
        |               |
       -------------------
       -------------------
        |               |
        -----------------

The first byte of the memory block contains the PID of the
process owning the block, this is the process the memory
block was allocated by (on process-load). If the PID
is '254', the block is free, if it is '255' the block has
been reserved by a process for dynamic memory block resizing
(remalloc). Reserved memory blocks will be used for allocating
(malloc) when there is not enough contigious memory free. The
next member variable determines the size in byte of the following
memory space. The rest of the block is the memory space whose
adress is returned by the malloc() kernel function.

The memory block header is defined in the s_mem struct:

	struct s_mem {

		unsigned char pid;	
		unsigned long size;

	};