Format of STARLITE (General Software's Embedded DOS) memory control block:
Offset  Size    Description
 00h    BYTE    block type: 5Ah if last block in chain, otherwise 4Dh
 01h    WORD    PSP segment of owner, 0000h if free, 0008h if belongs to DOS
 03h    WORD    size of memory block in paragraphs
 05h    BYTE    unused
 06h    WORD    segment address of next memory control block (0000h if last)
 08h    WORD    segment address of previous memory control block or 0000h
 0Ah  6 BYTEs   reserved