30-08-2014, 11:34 AM
Operating System
[attachment=67414]
What is OS?
Operating System is a software, which makes a computer to actually work.
The OS organizes and controls the hardware.
OS acts as an interface between the application programs and the machine hardware.
Examples: Windows, Linux, Unix and OS, etc.,
Structure of Operating System (Contd…):
The structure of OS consists of 4 layers:
Hardware:
Hardware consists of CPU, Main memory, I/O Devices, etc,
Software (Operating System):
Software includes process management routines, memory management routines, I/O control routines, file management routines.
Batch Processing:
In Batch processing same type of jobs batch (BATCH- a set of jobs with similar needs) together and execute at a time.
The OS was simple, its major task was to transfer control from one job to the next.
The job was submitted to the computer operator in form of punch cards. At some later time the output appeared.
Common Input devices were card readers and tape drives.
Real Time operating system
A Real time operating system process inputs simultneously,fast enough affort the next input process.
Real time system are usually used to control complex systems
Provides fault tolerance and graceful degradation capabilites
Multiprogramming:
Multiprogramming is a technique to execute number of programs simultaneously by a single processor.
In Multiprogramming, number of processes reside in main memory at a time.
The OS picks and begins to executes one of the jobs in the main memory.
If any I/O wait happened in a process, then CPU switches from that job to another job.
Hence CPU in not idle at any time.
Time Sharing operating system
Time sharing, or multitasking, is a logical extension of multiprogramming.
Multiple jobs are executed by switching the CPU between them.
In this, the CPU time is shared by different processes, so it is called as “Time sharing Systems”.
Time slice is defined by the OS, for sharing CPU time between processes.
Examples: Multics, Unix, etc.,
Distributed operating system
A distributed operating system is a system consisting of two or more nodes.
Some networking hardware ,and a capability of performing some of the control function of an O/S.
Resource sharing.
Reliability
[attachment=67414]
What is OS?
Operating System is a software, which makes a computer to actually work.
The OS organizes and controls the hardware.
OS acts as an interface between the application programs and the machine hardware.
Examples: Windows, Linux, Unix and OS, etc.,
Structure of Operating System (Contd…):
The structure of OS consists of 4 layers:
Hardware:
Hardware consists of CPU, Main memory, I/O Devices, etc,
Software (Operating System):
Software includes process management routines, memory management routines, I/O control routines, file management routines.
Batch Processing:
In Batch processing same type of jobs batch (BATCH- a set of jobs with similar needs) together and execute at a time.
The OS was simple, its major task was to transfer control from one job to the next.
The job was submitted to the computer operator in form of punch cards. At some later time the output appeared.
Common Input devices were card readers and tape drives.
Real Time operating system
A Real time operating system process inputs simultneously,fast enough affort the next input process.
Real time system are usually used to control complex systems
Provides fault tolerance and graceful degradation capabilites
Multiprogramming:
Multiprogramming is a technique to execute number of programs simultaneously by a single processor.
In Multiprogramming, number of processes reside in main memory at a time.
The OS picks and begins to executes one of the jobs in the main memory.
If any I/O wait happened in a process, then CPU switches from that job to another job.
Hence CPU in not idle at any time.
Time Sharing operating system
Time sharing, or multitasking, is a logical extension of multiprogramming.
Multiple jobs are executed by switching the CPU between them.
In this, the CPU time is shared by different processes, so it is called as “Time sharing Systems”.
Time slice is defined by the OS, for sharing CPU time between processes.
Examples: Multics, Unix, etc.,
Distributed operating system
A distributed operating system is a system consisting of two or more nodes.
Some networking hardware ,and a capability of performing some of the control function of an O/S.
Resource sharing.
Reliability