The operating system, in this case, goes to a translation table, and finds the filename that you have specified. The operating system must also make sure that the RAM is not currently being used by some other process or application. Then it must wait for the printer to become available. The operating system coordinates the system in much the same way as a good hotel manager keeps track of what's happening in a large hotel. The kitchen staff, the laundry staff and other groups act independently, but someone has to coordinate their efforts.
Guests occupy rooms temporarily.
Someone must coordinate which guest name goes with which room name, how many rooms are free, and where they are located. An operating system must control the microprocessors acting independently, making sure that they don't interfere with each other's functions, and must keep track of which filenames go with which cylinder, sector and track number, how much free space is available on a disk and where those free areas are located. An operating system translates commands that you type, or mouse movements that you make, into instructions to the various components of the system. Computers contain a small portion of memory which cannot be changed. This Read-Only Memory or ROM has a small program burned into it.