INT 2F U - NETWORK REDIRECTOR - GET DISK SPACE
AX = 110Ch
ES:DI -> current directory structure for desired drive
Return: AL = sectors per cluster
AH = media ID byte
BX = total clusters
CX = bytes per sector
DX = number of available clusters
Note:   called by DOS 3.1+ kernel

See also: 2136

2F110C - NETWORK REDIRECTOR - GET DISK SPACE