Format of parameter block for function 52h:
 00h	BYTE	(call) unused???	)
		(ret) 00h if flash/ATA drive but no card inserted
			unchanged otherwise
Notes:	the absense of a flash card should be tested by checking the DOS error
	  code rather than the returned byte
	the parameter byte is cleared to 00h erroneously by the Award
	  PCDISK.EXE v1.02c PCMCIA/ATA driver if no ATA card is inserted
	  (bug corrected in PCDISK.EXE v1.02h and later)
	not supported by the SystemSoft ATADRV.EXE and the Phoenix PCMATA.SYS
	  PCMCIA/ATA drivers