Format of 386MAX control block:
Offset	Size	Description	)
 00h	WORD	segment of next block (FFFFh if last)
 02h	WORD	segment of previous block (FFFFh if first)
 04h 12 BYTEs	filename
 10h	WORD	resident size in paragraphs
 12h	WORD	environment size???
 14h	WORD	real prsent environment size + 1 (0000h if ENVSAVE used)
 16h  2 BYTEs	???
 18h	DWORD	initial size or SIZE=n in 386LOAD commandline
 1Ch	DWORD	SIZE=-1 ???
 20h	DWORD	SIZE= ???
 24h	BYTE	PRGREG= if specified, else FFh
 25h	BYTE	ENVREG= if specified, else FFh
 26h	BYTE	FlexFrame (00h not present, 01h present)
 27h  3 BYTEs	???
 2Ah	BYTE	GROUP= or 00h if not present
 2Bh	BYTE	???
 2Ch	WORD	PSP