An operating system offers various services to both users and programs. It includes application programs that can be run within the operating system and provide an environment where they can be executed seamlessly. Thanks to its services, the operating system also offers users the convenience of running multiple programs.
Here is a list of standard services offered by almost all operating systems:
- User Interface
- Program Execution
- File system manipulation
- Input / Output Operations
- Communication
- Resource Allocation
- Error Detection
- Accounting
- Security and protection
This tutorial will briefly describe what services an operating system usually provides to users and those programs that are and will be running within it.
User Interface of Operating System
Usually, an Operating system comes in three forms or types. Depending on the interface, their types have been further subdivided. These are:
- Command line interface
- Batch based interface
- Graphical User Interface
Let's get to know each of them briefly.
The Command Line Interface (CLI) is an interface that uses text commands and a method for entering those commands. The Batch Interface (BI) utilizes commands and directives to manage the commands entered into files executed later. On the other hand, the Graphical User Interface (GUI) is a window system that uses a pointing device, such as a mouse or trackball, to interact with the interface. Users can choose from menus and make selections from a variety of lists. A keyboard is also used to enter text.
Program Execution in Operating System
The operating system must be able to load a program into memory and execute that program. Furthermore, the program must be able to terminate its execution, either normally or abnormally/forcefully.
File System Manipulation in Operating System
Operating systems have a file-handling feature that allows users to read and write programs as files and directories. This feature enables users to create or delete files with specific names and extensions, search for a particular file, and list file information. Additionally, some programs provide permissions management, which allows users to grant or deny access to files and directories based on file ownership.
I/O operations in Operating System
When a program runs, it may need I/O (Input/Output) operations to interact with files or other devices. However, users cannot directly control I/O devices for efficiency and security reasons. Therefore, the operating system provides a way to perform I/O operations, such as reading from and writing to files.
Communication System of Operating System
The process needs to communicate with another process to exchange information. Whether processes are executing on the same computer or different ones, operating systems provide communication support. Two main communication methods exist between two processes: shared memory and message passing.
Resource Allocation of Operating System
When multiple jobs are running concurrently, allocating resources to each is necessary. These resources may include CPU cycles, main memory storage, file storage, and I/O devices. CPU scheduling routines are employed to determine the best use of the CPU.
Error Detection
Errors may occur in CPU, memory, I/O devices, or user programs. The OS takes appropriate action for each error to ensure correct and consistent computing.
Accounting
This operating system service keeps track of which users are using how much and what kinds of computer resources have been used for accounting or to accumulate usage statistics.
Protection and Security
System resources must be accessed in a controlled manner. For security, users authenticate via login ID and password.