CHAPTER 1: INTRODUCTION TO OPERATING
SYSTEM
Introduction to Operating system
An operating system (OS) is system software that manages computer hardware and software
resources and provides common services for computer programs. All computer programs,
excluding firmware, require an operating system to function.
An operating system is a program that acts as an interface between the user and thecomputer
hardware and controls the execution of all kinds of application programs and assistant system
software programs (i.e. Utilities).
Basic importance of the operating system
1) Operating system behaves as a resource manager. It utilizes the computer in a cost effective
manner. It keeps account of different jobs and the where about of their results and locations
in the memory.
2) Operating system schedules jobs according to their priority passing control from one program
to the next. The overall function of job control is especially important when there are several
uses (a multi user environment)
3) Operating system makes a communication link user and the system and helps the user to run
application programs properly and get the required output
4) Operating system has the ability to fetch the programs in the memory when required and
not all the Operating system to be loaded in the memory at the same time, thus giving the
user the space to work in the required package more conveniently and easily
,5) Operating system helps the user in file management. Making directories and saving files in
them is a very important feature of operating system to organize data according to the
needs of the user
6) Multiprogramming is a very important feature of operating system. It schedules and
controls the running of several programs at ones
7) It provides program editors that help the user to modify and update the program lines
8) Debugging aids provided by the operating system helps the user to detect and rename
errors in programs
9) Disk maintenance ability of operating system checks the validity of data stored on diskettes
and other storage to make corrections to erroneous data
Operating Systems Terminology’s
Processes: A process is an instance of a program running in a computer.
A program in the execution is called a Process. Process is not the same as program. A process
is more than a program code (Program Code + Data + Execution status).
Files: A collection of data or information that has a name, called the filename. Almost all
information stored in a computer must be in a file. There are many different types of files: data
files, text files , program files, directory files, and so on. Different types of files store different
types of information. For example, program files store programs, whereas text files store text.
A system call is a way for programs to interact with the operating system. A computer
program makes a system call when it makes a request to the operating system's kernel. System
calls are used for hardware services, to create or execute a process, and for communicating
with kernel services, including application and process scheduling.
Shell AND kernel
A shell is a software interface that's often a command line interface that enables the user to
interact with the computer. Some examples of shells are MS-DOS Shell, command.com, csh,
ksh, and sh. Below is a picture and example of what a Terminal window with an open shell. A
Kernel is first section of the operating system to load into memory. As the center of the
operating system, the kernel needs to be small, efficient and loaded into a protected area in the
memory; so as not to be overwritten. It can be responsible for such things as disk drive
management, interrupt handler, file management, memory management, process management,
etc.
Virtual Machines: A virtual machine (VM) is a software program or operating system that not
only exhibits the behavior of a separate computer, but is also capable of performing tasks such
as running applications and programs like a separate computer. A virtual machine, usually
known as a guest is created within another computing environment referred as a "host." Multiple
virtual machines can exist within a single host at one time.
, The History of Operating Systems
The first operating system was created by General Motors in 1956 to run a single IBM
mainframe computer. Other IBM mainframe owners followed suit and created their own
operating systems. As you can imagine, the earliest operating systems varied wildly from one
computer to the next, and while they did make it easier to write programs, they did not allow
programs to be used on more than one mainframe without a complete rewrite.
In the 1960s, IBM was the first computer manufacturer to take on the task of operating system
development and began distributing operating systems with their computers. However, IBM
wasn't the only vendor creating operating systems during this time. Control Data Corporation,
Computer Sciences Corporation, Burroughs Corporation, GE, Digital Equipment Corporation,
and Xerox all released mainframe operating systems in the 1960s as well.
In the late 1960s, the first version of the Unix operating system was developed. Written in C, and
freely available during it's earliest years, Unix was easily ported to new systems and rapidly
achieved broad acceptance. Many modern operating systems, including Apple OS X and all
Linux flavors, trace their roots back to Unix.
Microsoft Windows was developed in response to a request from IBM for an operating system
to run its range of personal computers. The first OS built by Microsoft wasn't called Windows, it
was called MS-DOS and was built in 1981 by purchasing the 86-DOS operating system from
Seattle Computer Products and modifying it to meet IBM's requirements. The name Windows
was first used in 1985 when a graphical user interface was created and paired with MS-DOS.
Apple OS X, Microsoft Windows, and the various forms of Linux (including Android) now
command the vast majority of the modern operating system market.
The First Generation (1940's to early 1950's)
When electronic computers where first introduced in the 1940's they were created without any
operating systems. All programming was done in absolute machine language, often by wiring up
plugboards to control the machine's basic functions. During this generation computers were
generally used to solve simple math calculations, operating systems were not necessarily needed.
The Second Generation (1955-1965)
The first operating system was introduced in the early 1950's, it was called GMOS and was
created by General Motors for IBM's machine the 701. Operating systems in the 1950's were
called single-stream batch processing systems because the data was submitted in groups. These
new machines were called mainframes, and they were used by professional operators in large
computer rooms. Since there was such as high price tag on these machines, only government
agencies or large corporations were able to afford them.
The Third Generation (1965-1980)
By the late 1960's operating systems designers were able to develop the system of
multiprogramming in which a computer program will be able to perform multiple jobs at the
SYSTEM
Introduction to Operating system
An operating system (OS) is system software that manages computer hardware and software
resources and provides common services for computer programs. All computer programs,
excluding firmware, require an operating system to function.
An operating system is a program that acts as an interface between the user and thecomputer
hardware and controls the execution of all kinds of application programs and assistant system
software programs (i.e. Utilities).
Basic importance of the operating system
1) Operating system behaves as a resource manager. It utilizes the computer in a cost effective
manner. It keeps account of different jobs and the where about of their results and locations
in the memory.
2) Operating system schedules jobs according to their priority passing control from one program
to the next. The overall function of job control is especially important when there are several
uses (a multi user environment)
3) Operating system makes a communication link user and the system and helps the user to run
application programs properly and get the required output
4) Operating system has the ability to fetch the programs in the memory when required and
not all the Operating system to be loaded in the memory at the same time, thus giving the
user the space to work in the required package more conveniently and easily
,5) Operating system helps the user in file management. Making directories and saving files in
them is a very important feature of operating system to organize data according to the
needs of the user
6) Multiprogramming is a very important feature of operating system. It schedules and
controls the running of several programs at ones
7) It provides program editors that help the user to modify and update the program lines
8) Debugging aids provided by the operating system helps the user to detect and rename
errors in programs
9) Disk maintenance ability of operating system checks the validity of data stored on diskettes
and other storage to make corrections to erroneous data
Operating Systems Terminology’s
Processes: A process is an instance of a program running in a computer.
A program in the execution is called a Process. Process is not the same as program. A process
is more than a program code (Program Code + Data + Execution status).
Files: A collection of data or information that has a name, called the filename. Almost all
information stored in a computer must be in a file. There are many different types of files: data
files, text files , program files, directory files, and so on. Different types of files store different
types of information. For example, program files store programs, whereas text files store text.
A system call is a way for programs to interact with the operating system. A computer
program makes a system call when it makes a request to the operating system's kernel. System
calls are used for hardware services, to create or execute a process, and for communicating
with kernel services, including application and process scheduling.
Shell AND kernel
A shell is a software interface that's often a command line interface that enables the user to
interact with the computer. Some examples of shells are MS-DOS Shell, command.com, csh,
ksh, and sh. Below is a picture and example of what a Terminal window with an open shell. A
Kernel is first section of the operating system to load into memory. As the center of the
operating system, the kernel needs to be small, efficient and loaded into a protected area in the
memory; so as not to be overwritten. It can be responsible for such things as disk drive
management, interrupt handler, file management, memory management, process management,
etc.
Virtual Machines: A virtual machine (VM) is a software program or operating system that not
only exhibits the behavior of a separate computer, but is also capable of performing tasks such
as running applications and programs like a separate computer. A virtual machine, usually
known as a guest is created within another computing environment referred as a "host." Multiple
virtual machines can exist within a single host at one time.
, The History of Operating Systems
The first operating system was created by General Motors in 1956 to run a single IBM
mainframe computer. Other IBM mainframe owners followed suit and created their own
operating systems. As you can imagine, the earliest operating systems varied wildly from one
computer to the next, and while they did make it easier to write programs, they did not allow
programs to be used on more than one mainframe without a complete rewrite.
In the 1960s, IBM was the first computer manufacturer to take on the task of operating system
development and began distributing operating systems with their computers. However, IBM
wasn't the only vendor creating operating systems during this time. Control Data Corporation,
Computer Sciences Corporation, Burroughs Corporation, GE, Digital Equipment Corporation,
and Xerox all released mainframe operating systems in the 1960s as well.
In the late 1960s, the first version of the Unix operating system was developed. Written in C, and
freely available during it's earliest years, Unix was easily ported to new systems and rapidly
achieved broad acceptance. Many modern operating systems, including Apple OS X and all
Linux flavors, trace their roots back to Unix.
Microsoft Windows was developed in response to a request from IBM for an operating system
to run its range of personal computers. The first OS built by Microsoft wasn't called Windows, it
was called MS-DOS and was built in 1981 by purchasing the 86-DOS operating system from
Seattle Computer Products and modifying it to meet IBM's requirements. The name Windows
was first used in 1985 when a graphical user interface was created and paired with MS-DOS.
Apple OS X, Microsoft Windows, and the various forms of Linux (including Android) now
command the vast majority of the modern operating system market.
The First Generation (1940's to early 1950's)
When electronic computers where first introduced in the 1940's they were created without any
operating systems. All programming was done in absolute machine language, often by wiring up
plugboards to control the machine's basic functions. During this generation computers were
generally used to solve simple math calculations, operating systems were not necessarily needed.
The Second Generation (1955-1965)
The first operating system was introduced in the early 1950's, it was called GMOS and was
created by General Motors for IBM's machine the 701. Operating systems in the 1950's were
called single-stream batch processing systems because the data was submitted in groups. These
new machines were called mainframes, and they were used by professional operators in large
computer rooms. Since there was such as high price tag on these machines, only government
agencies or large corporations were able to afford them.
The Third Generation (1965-1980)
By the late 1960's operating systems designers were able to develop the system of
multiprogramming in which a computer program will be able to perform multiple jobs at the
