Operating System Services | Readstall

Operating System Services

04-02-19 Afreen Shaik 0 comment

An operating system provides an environment for the execution of programs.It provides certain services to programs and to the users of those programs.It differ from one operating system to another.These operating system services provided for the convenience of the programmer, to make the programming task easier.The following functions that are helpful to the user.

  • USER INTERFACE: All operating systems have a user interface(UI).This interface can take several forms. One is a command-line interface(CLI),which uses text commands and a method for entering them.Another is a batch interface,in which commands and directives to control those commands are entered into files,and those files are executed.Most commonly, a graphical user interface(GUI)is used Some systems provides two or all three of these variations.
  • PROGRAM EXECUTION: The system must be able to load a program into memory and to run that program.The program must be able to end its execution,either normally or abnormally.
  • I/O OPERATIONS: A running program may require I/O, which may involve a file or an I/O device.For efficiency and protection, users usually cannot control I/O devices directly.
  • FILE SYSTEM MANIPULATION: The file system is of particular interest.Obviously, programs need to read and write files and directories. They also need to create and delete them by name,search for a given file.Many operating systems provides a variety of file systems,sometimes to allow personal choice and sometimes to provide specific features or performance characteristics.
  • COMMUNICATION: There are many circumstances in which one process needs to exchange information with another process.Such communication may occur between processes that are executing on the same computer or on different computer systems tied together by a computer network.Communications many be implemented by the shared memory, in which two or more processes read and write to a shared section of memory,or message passing.
  • ERROR DETECTION: The operating systems needs to be detecting and correcting errors constantly.Errors may occur in the CPU and the memory hardware,In I/O devices and in the user program.For each type of error,the operating system should take the appropriate action to ensure correct and consistent computing. Sometimes it has no choice but to halt the system.
  • RESOURCE ALLOCATION: When there are multiple users or multiple jobs running at the same time,resources must be allocated to each of them.The operating system manages many type of resources. Some may have special allocation code,whereas others may have more general request and release code.In determining how best to use the CPU, operating systems have CPU-scheduling routines that take into account the speed of the CPU. There may also be routines to allocate printers,USB storage drives,and other peripheral devices.
  • ACCOUNTING: We want to keep track of which users use how many much and what kinds of computer resources. This record keeping may be used for accounting or accumulating usage statistics. Usage statistics may be a valuable tool for reasearchers who wish to reconfigure the system to improve computing services.
  • PROTECTION AND SECURITY: The owners of information stored in a multi user or networked computer system may want to control use of that information. It is not possible for one process to interfere with the others or with the operating system. Security of the system from outsider is also important. Such security starts with requiring each user to authenticate himself or herself to the system, usually by means of a password, to gain access to system resources.







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