Format of DR DOS 5.0-6.0 internal variable table:
Offset	Size	Description	)
 00h	WORD	???
 02h	WORD	segment of ???
 04h	WORD	offset within DOS data segment of history control structure
		  for COMMAND.COM history buffer (see #01586)
 06h	WORD	offset within DOS data segment of history control structure
		  for application history buffer (see #01586)
 08h	BYTE	initial history state flags (see #01583)
 09h  2 BYTEs	???
 0Bh	WORD	KB of extended memory at startup
 0Dh	BYTE	number of far jump entry points
 0Eh	WORD	segment containing far jumps to DR DOS entry points (see #01587)
 10h	WORD	(only if kernel loaded in HMA) offset in HMA of first free HMA
		  memory block (see #01588) or 0000h if none; segment is FFFFh
 12h	WORD	pointer to segment of environment variables set in CONFIG,
		  or 0000h if already used
---DR DOS 6.0---
 14h	WORD	(only if kernel loaded in HMA) offset in HMA of first used HMA
		memory block (see #01588) or 0000h if none; segment is FFFFh
 16h  8 BYTEs	???
 1Eh	WORD	offset in DOS data segment of full COUNTRY.SYS filename
 20h  8 BYTEs	???
 28h	WORD	offset in DOS data segment of SHARE hook table
 2Ah  2 BYTEs	???
 2Ch	WORD	offset in DOS data segment of far pointer to INT 2F/AX=1000h
		  handler
Notes:	the segment used for the DR DOS 6.0 CONFIG environment variables
	  (excluding COMSPEC, VER and OS) is only useful for programs/drivers
	  called from CONFIG.SYS. The word is set to zero later when the area
	  is copied to the COMMAND.COM environment space.  This allows
	  CONFIG.SYS to pass information to AUTOEXEC.BAT.
	the Novell DOS 7 KEYB uses offsets 10h,14h, and 2Ch in the same was
	  as for DR DOS 6.0, so it is likely that the entire table is the same