Fcbs
Specifies the number of file control blocks (FCBs) that the MS-DOS subsystem can have open at the same time. Use the systemroot\System32\Config.nt file, or the equivalent startup file specified in a program's PIF, to specify the number of FCBs.
A file control block is a data structure that stores information about a file.
fcbs=x
Parameter
x
Specifies the number of FCBs that the MS-DOS subsystem can have open at one time. Valid values for x are in the range 1 through 255. The default value is 4.
Windows 2000 Command Reference Main Page
Fcbs Notes
Fcbs Example