DOS Operating System DOS Operating System has a total of 4 components: File system, Process Manager, Memory Manager and Network Manager. There is a fifth component, IO Manager, but since DOS doesn't have a user interface it does not contain this component. 1. File system The file system for DOS is a FAT16 system, its able to keep track of where the files were on your computer. Although, al l files on the system are limited to eight characters and a three letter extension. The MS-DOS filesystem also has a limit of approximately 2.1 Gigabytes. 2. Process Manager DOS is a FIFO processor (First In First Out) meaning it can only do one task at a time. 3. Memory Manager DOS comes with the standard extended memory manager called HIMEM.SYS The amount of memory present (and available) in a system can be found by running the following command: " mem " (or " mem /c |more " for more detailed information). 4. Network Manager In DOS