sentences:  The most widespread file system along MK-DOS users was MicroDOS.It did not support file fragmentation (like the file system used with RT-11) and required frequent spatial reallocation to maintain optimum contiguous free space (RT-11 users would use the 'SQUEEZE' command, which worked the same way as the *COMPACT command on Acorn's DFS for the BBC Micro).Although MK-DOS was incompatible with the RT-11's file system, both shared many principles.