Various Operating system services




Services of an Operating System

Operating System provides numerous crucial services to the user as well as to the application programs. We can broadly classify these services into following five categories:

  1. Process management
  2. Device management
  3. Inter-process Communication
  4. File management
  5. Error detection

Process management:

This is one of the most important roles played by an operating system. Whenever a user writes a program he is simply concerned with its logic, he never needs to bother, how long the code is, how much time will it take to be executed, what amount of space will it occupy in the memory, where will it be stored etc. This is because the operating system handles all these issues.

Initially the program is in hard disk only. Now the OS brings it to the main memory and schedules it to access the CPU. It also takes care whether the entire program or some part of the program needs to be brought in the main memory.
 

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Various Operating system services

Fig. Multiprogramming (Multiple programs residing in the main memory at one time)

During execution, one process might require accessing I/O devices and till then CPU might remain idle. But OS won’t let this happen because it always ensures that several processes are residing in the main memory at one time (i.e., basic concept of multiprogramming)

Device management:

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We know that every program needs to perform Input and output operations during its execution but the user never needs to interact with the hardware devices directly and this is all because of operating system.
 

Various Operating system services

Fig. Device Management by Operating System

We can simply assume that till the time user performs coding, control is in his hand and whenever some I/O operation needs to be performed, the control is transferred to the operating system and once the I/O work is done, the control is transferred back to the user. In this way, OS does device management.

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Inter-process Communication:

There are two types of processes. First ones are the independent processes which never need to communicate with each other and run independently.

Another type of processes are mutually dependent processes which work with mutual co-operation and hence they need to communicate with other.

For example, there are two processes, first one is meant to send some data and the second one is there to receive the same data. Now, if the two processes are unable to communicate with each other, several problems might arise like:

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  • Data might be lost
  • If the two are not running with the same pace, slower one will be overwhelmed.
  • If the two processes run without mutual co-operation, efforts of the faster process will be wasted and thereby CPU’s time is wasted too.

Various Operating system services

Fig. Inter Process Communication


 

So, communication is a must between one or more mutually dependent processes. For this, operating system provides two types of inter-process communication mechanisms:

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  1. Message Passing: Here processes communicate with each other by exchange of messages.
  2. Shared memory: In this mechanism, two or more processes share a common memory space and access it by mutually communicating with each other.

File Management:

This is another important service provided by the operating system. It mainly deals with the secondary memory management.
We know that all the processes require to access files at some time. They might need to read data from files, write data into them, edit them etc. But the user never needs to do anything here because the operating system acts as a file manager and provides the necessary file and folder related services to the programs in run.

Most common file and folder services provided by the operating system include:

  1. Creating files
  2. Opening files
  3. Renaming files
  4. Copying files
  5. Deleting files
  6. Searching for files
  7. Modifying files, their attributes and access permissions.


 

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Various Operating system services

Fig. Operating System acts as a file manager

 

Error Detection:

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An error might occur anytime in between the execution of a program and may hamper the execution process.

Therefore, the operating system keeps on detecting the errors continuously while the process is in run. This is quite like the I/O management service. If program runs smoothly, the user has the control but as soon as any error arises, control is transferred to the operating system which then does the necessary subsequent action.

This service can’t be allowed to the user because this may lead to misallocation or deallocation of memory or CPU’s access.

More Details….

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Frequently Asked Questions

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Ans: Real time operating System (RTOS) is an operating system that serves the real-time systems. Before understanding the term “Real Time Operating System” we need to understand the two terms it comprises of i.e., Real Time Systems and Operating System. view more..
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Ans: Network Operating System is a collection of various computers which are all connected to a single host computer. It can be compared to a client – server architecture where the host computer acts as a server and rest of the systems act as clients which take services from the common server and access its resources also. view more..
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Ans: Distributed Operating System is a recent advancement in the world of computer technology and are being widely accepted all-over the world and, that too, with a great pace view more..
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Ans: We can broadly classify these services into following five categories: Process management Device management Inter-process Communication File management Error detection view more..
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Ans: there are 4 types of architectures of operating system: 1. Monolithic architecture 2. Layered architecture 3. Microkernel architecture 4. Hybrid architecture view more..
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Ans: It is the oldest architecture of the operating system. We know that all the core software components of the operating system are collectively known as the kernel. view more..
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Ans: This is an important architecture of operating system which is meant to overcome the disadvantages of early monolithic systems. view more..
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Ans: The basic ideology in this architecture is to keep the kernel as small as possible. We know that kernel is the core part of the operating system and hence it should be meant for handling the most important services only. view more..
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Ans: the idea was to combine the best functionalities of all old approaches and hence this design is termed as the hybrid structured operating system. view more..
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Ans: System Calls and Programs All the present-day operating systems support the following two modes of operation for the CPU: User mode Kernel mode view more..
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Ans: A batch system executes jobs, whereas a time-shared system has user programs, or tasks. Even on a single-user system such as Microsoft Windows, a user may be able to run several programs at one time: a word processor, a web browser, and an e-mail package. Even if the user can execute only one program at a time, the operating system may need to suppoft its own internal programmed activities, such as memory management. view more..
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Ans: Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor or the ability to allocate tasks between them. view more..
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Ans: Process scheduling selects processes from the queue and loads them into memory for execution. Process loads into the memory for CPU scheduling. The primary objective of the job scheduler is to provide a balanced mix of jobs, such as I/O bound and processor bound. ... Time-sharing operating systems have no long term scheduler. view more..
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Ans: Inter process communication (IPC) is a mechanism which allows processes to communicate each other and synchronize their actions. The communication between these processes can be seen as a method of co-operation between them. Processes can communicate with each other using these two ways: Shared Memory. Message passing. view more..
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Ans: Direct memory access (DMA) is a method that allows an input/output (I/O) device to send or receive data directly to or from the main memory, bypassing the CPU to speed up memory operations. The process is managed by a chip known as a DMA controller (DMAC) view more..
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Ans: An instruction cycle (sometimes called a fetch–decode–execute cycle) is the basic operational process of a computer. It is the process by which a computer retrieves a program instruction from its memory, determines what actions the instruction dictates, and carries out those actions. view more..
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Ans: System programs provide a convenient environment for program development and execution. Some of them are simply user interfaces to system calls; others are considerably more complex view more..
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Ans: After an operating system is generated, it must be made available for use by the hardware. But how does the hardware know where the kernel is or how to load that kernel? The procedure of starting a computer by loading the kernel is known as booting the system. view more..




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