Page 41 - DCAP507_SYSTEM_SOFTWARE

Unit 2: Evolution of Operating System

Notes

Task Illustrate the function of virtual machines.

Self Assessment

Fill in the blanks:

5. The services like system calls provide by the operating system are requested by putting
the parameters in well-defined places, such as in registers or on the stack, and then executing
a special trap instruction known as a ..............................
6. Layer 2 handled .............................. between each process and the operator console.
7. In .............................., all the kernel does is handle the communication between clients and
servers.
8. A .............................. is a type of computer application used to create a virtual environment,
which is referred to as virtualization.

2.3 User Function of Operating System

An operating system manages all aspects of a complex system.
Imagine what will happen if three programs running on a computer all try to print their output
simultaneously on the same printer. The first few lines might be from program one and the next
few lines might be from program two and so on with the result resulting in chaos. The operating
system can bring order to potential chaos by buffering all the output destined for the printer on
the disk.
The primary task of operating system is to keep track of who is using which resource, to grant
resource request, to account for usage, and to meditate conflicting request from different programs
and users.
Figure 2.11: Abstract View of OS as Intermediary

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