MAX-FILES* - This variable sets the maximum number of files that can be opened by the runtime system. The default value is "32". Keeping this value small conserves memory. Many operating systems limit the number of files that can be opened by a single process, so you may have to make some adjustments there too. The highest allowable value of MAX-FILES varies with the operating system:
System Max value
UNIX, MPE/iX, VMS: 255
MS-DOS, OS/2, Windows: 128
Windows NT 4.0 (32-bit): 256
Windows NT 4.0 (16-bit): 120
Windows NT 3.51 or lower: 64