Int 2F/AX=5758h/BX=4858h

AX = 5758h
BX = 4858h ('HX')
DX = 4443h ('DC')
CX <> 5758h

Return:
BX = 6878h if installed
DX = 6463h if installed
CX = version (CH=major,CL=minor)

Program: CACHECLK is a 'Cloaked' disk cache by Helix Software

Note: Returns with registers unchanged if CX=5758h on entry

See Also: INT 16/AX=5758h/BX=4858h - INT 2F/AX=4310h"Cloaking"