Format of SuperStor CVF compressed unit structure:
Offset	Size	Description	)
 00h 31 BYTEs	BIOS parameter block for compressed drive (see #01663)
 1Fh  5 BYTEs	reserved for future expansion of the BPB
 24h 33 BYTEs   DOS 4-6 style drive parameter block for compressed drive
		  (see #01395)
 45h  2 BYTEs	reserved for future expansion of the DPB
 47h	WORD	first sector of relocation table (RBT)
 49h	WORD	first sector of file allocation table
 4Bh	WORD	first sector of the data area
 4Dh	BYTE	sec2byteshift
 4Eh  2 BYTEs	???
		Note:	Reportedly these two bytes did not exist in ADDSTOR's
			  specification, so the whole structure would have
			  been documented differently.
 50h	WORD	sectors per cluster
 52h	BYTE	sector shift
 53h	WORD	compression ratio
 55h	DWORD	number of physical sectors in the host file
 59h	WORD	OS version
 5Bh	BYTE	SuperStor level
 5Ch	BYTE	unknown???
 5Dh	BYTE	flags
		bits 7-1: ???
		bit 0: drive is mounted
 5Eh	BYTE	unknown???
 5Fh	DWORD	pointer to CVF's underlaying host DCB
		this should be the physical DPB for this unit
		    ->  +00h BYTE host unit DOS unit number
		        +01h BYTE CVF's driver host subunit number
Note:	As this SuperStor compressed unit structure's structure is located
	  within the segment the SuperStor driver has occupied, the segment
	  value of its address can be used as an installation check, since it
	  contains the signature "ADDSTOR" at offset 20h in the SuperStor
	  driver.  This is used by Novell DOS 7 WINSWAP.SYS to check for the
	  presence of SuperStor.
SeeAlso: #04114
Index:	installation check;SuperStor