INT 10 - FRIEZE v7.41+ - INSTALLATION CHECK
AH = 0Fh
SI = F123h
DI = 321Fh
Return: AH = number of character columns
AL = display mode (see AH=00h)
BH = active page (see AH=05h)
SI = DI = F345h if installed
Notes:  if mode was set with bit 7 set ("no blanking"), the returned mode will
also have bit 7 set
EGA, VGA, and UltraVision return either AL=03h (color) or AL=07h
(monochrome) in all extended-row text modes
SeeAlso: AH=4Bh"FRIEZE"

See also: 100F

100F - FRIEZE v7.41+ - INSTALLATION CHECK