 The variables also control some settings for the DOS as well as for programs, for example the format of date and time to be displayed (the choice is between the "European" DD-MM-YY and 24-hour clock, and "American" MM-DD-YY and 12-hour clock).Thanks to some form of virtual filesystem, practically any filesystem can be directly accessed, if an appropriate filesystem driver exists and was loaded to the memory.Up to eight such drivers can be installed at a time.