Many programs need to perform the same operations, such as accessing the network, playing sound, or drawing something on the screen. Libraries provide a common set of software routines (also known as functions, methods, procedures, or subroutines, or functions) which programs access to perform these common operations. This eliminates the need for each program to contain duplicate code for these common operations, which reduces software duplication and program size. Although additional libraries may be installed on the computer, the system libraries provided as part of the operating system provide the most broadly-used routines required by nearly every program.