Page 51 - DCAP507_SYSTEM_SOFTWARE

Unit 2: Evolution of Operating System

Self Assessment Notes

Fill in the blanks:
13. In computing, a .................................. is an instance of a computer program that is being
sequentially executed.

14. The speed of I/O that depends on .................................. storage management is critical to the
speed of many programs.
15. An .................................. is one part of the system that may cause malfunctioning of the
complete system.

2.6 Summary

 The main difference between the operating system and system software is that the operating
system runs in kernel or supervisor mode where as the system software and applications
run in user mode.

 Operating systems have evolved via number of distinct stages or generations which matches
approximately to the decades.

 The simplest of all the computer systems is a single use-single processor system which has
a single processor, runs a single program and interacts with a single user at a time.
 The main function of a batch processing system is to automatically keep executing one job
to the next job in the batch.
 A real-time system is used when there are rigid time requirements on the operation of a
processor or the flow of data, and thus is often used as a control device in a dedicated
application.
 A virtual machine is a type of computer application used to create a virtual environment,
which is referred to as virtualization.
 The operating system structure is a container for a collection of structures for interacting
with the operating system's file system, directory paths, processes, and I/O subsystem.

 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.
 Operating systems perform basic tasks, such as recognizing input from the keyboard,
sending output to the display screen, keeping track of files and directories on the disk, and
controlling peripheral devices such as disk drives and printers.
 The operating system provides an environment where the user can conveniently run programs.

2.7 Keywords

Batch Processing: A mode of data processing in which a number of tasks are lines up and the
entire task set is submitted to the computer in one go.
Client-Server Model: In client-Server Model, all the kernels handle the communication between
clients and servers by splitting the operating system up into parts, each of which only handles
one fact of the system, such as file service, process service, terminal service, or memory service.
Communications: These programs provide the mechanism for creating virtual connections among
processes, users, and different computer systems.

LOVELY PROFESSIONAL UNIVERSITY 45