Obvious problems like this I/O programming and formatting prompted interest in common, efficient, debugged
programs that different programmers could easily reuse.
At first such code came into use as libraries of standard ???routines.??? Later, computer scientists created the
first ???resident monitors??? or ???operating systems??? os which made it easier for programmers to use such shared
code, and made use of the machine more efficient and secure.
The operating system of a computer is a program, often called the ???kernel,??? which is always running on the
computer, and which governs the execution of all the other programs that run on the computer. The operating
system makes it much easier to write programs and execute them, because the operating system handles all the
complex details, like performing I/O and formatting input and output.
Two or three key motivations lay behind the development of the first operating systems. The first was to
make the computer much more easily useful. The second was to use what were at the time very expensive computing
resources efficiently. The third was to provide security and reliability in computing.
In general, operating systems are programs written to run on the bare machine and provide services to user
programs.
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