FCBS--Notes

Limitation on opening files

If a program tries to open more than x files by using file control blocks,  
MS-DOS might close the files that were opened earlier.

Recommended use of the FCBS command

You should use the FCBS command only if a program requires you to do so.
Most newer programs do not require file control blocks. However, some older
programs might require you to use the FCBS command in your CONFIG.SYS file.

Many programs use file handles. You can specify the number of file handles
available using the <FILES> command.