DTA - Disk Transfer Area (partially undocumented)

	DTA contains data, of which the first 21 bytes (00-15h) are known
	as being "reserved for DOS use on subsequent find next calls"

     Offset Size	   Description

	00   byte	attribute of search (undocumented)
	01   byte	drive used in search  (undocumented)
	02  11bytes	search name used (undocumented)
	0D   word	directory entry number (0 based, DOS 3.x+, undoc.)
	0F   word	starting cluster number of current directory
			zero for root directory	(DOS 3.x+, undocumented)
	11   word	reserved (undocumented)
	13   word	starting cluster number of current directory
			zero for root directory	(DOS 2.x+, undocumented)
	15   byte	attribute of matching file
	16   word	file time  (see FILE ATTRIBUTES)
	18   word	file date  (see FILE ATTRIBUTES)
	1A  dword	file size
	1E 13bytes	ASCIIZ filename and extension in the form NAME.EXT
			with blanks stripped


	- fields of DTA change dependent upon function call in progress
	- the DTA cannot span a 64K segment boundary
	- for compatibility with CP/M the default DTA is at offset 80h
	  in the PSP;  this area is also used for the command tail. To
	  avoid collision, set another DTA (INT 21,1A) or preserve the
	  command tail before using FCB function calls

	- see  INT 21,4E  INT 21,1A  INT 21,2F