One important issue is: how does one use the services efficiently? In addition to the device handling utilities, most OSs provide many other general purpose utilities as a set of packaged tools. The tools help us to think in terms of higher level of operations. In the absence of tools and tool kits we would be required to write a fresh program each time.
Operating Systems/Introduction to Operating System Lecture Notes
PCP Bhatt/IISc, Bangalore M1/V1/June 04/13
As an example, consider a sort utility in UNIX. It supports identification of fields in a file with multi field structured data. Sort allows us to sort on a chosen field on a file. Imagine if we had to write a sort program every time we had a set of records making a file. Also look at the support we derive from the compression software tools like compression of files for long-term storage or transmission (Zip tools in windows environment). It would be stupendous task to write a compression program for every file transfer.