Which one among the following tasks is NOT carried out by an operating system?

The correct answer is A, To link a program with the subroutines it references. Joining a program to the library routines it calls is the job of a linker, a separate system utility, not of the operating system.

When a program is compiled, the compiler produces object code that still contains calls to subroutines kept elsewhere, such as library functions. A linker, also called a link editor, resolves these references and combines the pieces into one executable file. The operating system then loads and runs that file. Its own core duties are process management, memory management, device or input-output management, file management and providing an interface between the user and the hardware.

B is wrong because controlling data transfer to and from printers, disks and other peripherals is device management, a basic OS duty. C is wrong because allocating and freeing main memory for programs is memory management, also done by the OS. D is wrong because the OS gives users a command line or graphical shell that sits as a layer over the hardware.

Exam tip: compiler translates, linker joins object code with libraries, loader puts the program in memory, and the OS manages everything that runs.