Format of PC-Cache internal data:
Offset	Size	Description	)
-1Ch 20 BYTEs	cached drive list, one byte per drive A: to T:
		each byte is either blank (20h) or drive letter (41h-54h)
 -8	BYTE	???
 -7	WORD	number of physical transfers (scaled down to 0000h-7FFFh)
 -5	WORD	number of saved transfers (scaled down to 0000h-7FFFh)
 -3   3 BYTEs	???