Operating System
An operating system is an integrated set of programs that controls the resources (the CPU, memory, I/O devices) of a computer system and provides its users with an interface or virtual machine that is more convenient to use than bare machine. An operating system is a group of computer programs that coordinates all the activities among computer hardware devices. It is the first program loaded into the computer by a boot program and remains in memory at all times.
Main Functions of Operating System
The main functions performed by most operating systems of today are as follows:
1. Process Management - The process management module of an operating system takes care of the creation and deletion of process, scheduling of various system resources to the different processes requesting them, and providing mechanisms for synchronization and communication among process.
2. Memory Management - The memory management module of an operating system takes care of the allocation and de allocation of memory space to the various programs in need of these resources.
3. File Management - The file management module of an operating system takes care of file-related activities such as organization, storing, retrieval, naming, sharing, and protection of files. The operating system handles the organization and tracking of files and directories (folders) saved or retrieved from a computer disk. The file management system allows the user to perform such tasks as creating files and directories, renaming files, coping and moving files, and deleting files. The operating system keeps track of where files are located on the hard drive through the type of file system. The type two main types of file system are File Allocation table (FAT) or New Technology File system (NTFS).
4. Security – The security module of an operating system protects the resources and information of a computer system against destruction and unauthorized access.
5. Command Interpretation – The command interpretation module of an operating system takes care of interpreting user commands, and directing the system resources to handle the requests. With this mode of interaction with the system, the user is usually not too concerned with the hardware details of the system.
6. Resource Management – The operating system manages system resources such as the computer's memory and sharing of the central processing unit (CPU) time by various applications or peripheral devices. Programs and input methods are constantly competing for the attention of the CPU and demand memory, storage and input/output bandwidth. The operating system ensures that each application gets the necessary resources it needs in order to maximize the functionality of the overall system.
In addition to the above listed major functions, an operating system also performs few other functions such as keeping an account of which users (or process) use how much and what kinds of computer resources, maintenance of log system usage by all users, and maintenance of internal time clock.
Role of an Operating System
as a Resource Manager:
The important objective of an operating system is to manage the various resources of the computer system. This involves performing such tasks as keeping track of who is using which resource, granting resource requests, accounting for resource usage, and mediating conflicting requests from different program and users. The efficient and fair sharing of resources among users and program is a key goal of most operating systems.
Operating system is known as resource manager because it controls all the activities of computer system and acts as an interface between user and hardware. Alternatively resource manager means anything which controls the professional activities of a performer... And this is what the operating system does so it is also known as resource manager.
• From the computer's point of view, the OS is the program most intimately involved with the hardware. In this context, we can view an OS as a resource allocator.
• Resource - ``Something valuable'' e.g. CPU time, memory space (RAM), file-storage space, I/O devices (disk), and so on.
• The OS acts as the manager of these resources. Includes multiplexing (sharing) resources in two different ways. "in time" and "in space".
An operating system is an integrated set of programs that controls the resources (the CPU, memory, I/O devices) of a computer system and provides its users with an interface or virtual machine that is more convenient to use than bare machine. An operating system is a group of computer programs that coordinates all the activities among computer hardware devices. It is the first program loaded into the computer by a boot program and remains in memory at all times.
Main Functions of Operating System
The main functions performed by most operating systems of today are as follows:
1. Process Management - The process management module of an operating system takes care of the creation and deletion of process, scheduling of various system resources to the different processes requesting them, and providing mechanisms for synchronization and communication among process.
2. Memory Management - The memory management module of an operating system takes care of the allocation and de allocation of memory space to the various programs in need of these resources.
3. File Management - The file management module of an operating system takes care of file-related activities such as organization, storing, retrieval, naming, sharing, and protection of files. The operating system handles the organization and tracking of files and directories (folders) saved or retrieved from a computer disk. The file management system allows the user to perform such tasks as creating files and directories, renaming files, coping and moving files, and deleting files. The operating system keeps track of where files are located on the hard drive through the type of file system. The type two main types of file system are File Allocation table (FAT) or New Technology File system (NTFS).
4. Security – The security module of an operating system protects the resources and information of a computer system against destruction and unauthorized access.
5. Command Interpretation – The command interpretation module of an operating system takes care of interpreting user commands, and directing the system resources to handle the requests. With this mode of interaction with the system, the user is usually not too concerned with the hardware details of the system.
6. Resource Management – The operating system manages system resources such as the computer's memory and sharing of the central processing unit (CPU) time by various applications or peripheral devices. Programs and input methods are constantly competing for the attention of the CPU and demand memory, storage and input/output bandwidth. The operating system ensures that each application gets the necessary resources it needs in order to maximize the functionality of the overall system.
In addition to the above listed major functions, an operating system also performs few other functions such as keeping an account of which users (or process) use how much and what kinds of computer resources, maintenance of log system usage by all users, and maintenance of internal time clock.
Role of an Operating System
as a Resource Manager:
The important objective of an operating system is to manage the various resources of the computer system. This involves performing such tasks as keeping track of who is using which resource, granting resource requests, accounting for resource usage, and mediating conflicting requests from different program and users. The efficient and fair sharing of resources among users and program is a key goal of most operating systems.
Operating system is known as resource manager because it controls all the activities of computer system and acts as an interface between user and hardware. Alternatively resource manager means anything which controls the professional activities of a performer... And this is what the operating system does so it is also known as resource manager.
• From the computer's point of view, the OS is the program most intimately involved with the hardware. In this context, we can view an OS as a resource allocator.
• Resource - ``Something valuable'' e.g. CPU time, memory space (RAM), file-storage space, I/O devices (disk), and so on.
• The OS acts as the manager of these resources. Includes multiplexing (sharing) resources in two different ways. "in time" and "in space".
- When a resource is time multiplexed different programs or different users gets their turn to use that resource. e.g.: Printer.
- When a resource is space multiplexed instead of taking turns, the resource is shared among them, i.e. each one gets a part of the resource. e.g.: Sharing main memory, hard disk etc.
- devices are expensive,
- there is need to share data as well as communicate
- how to allocate them to specific programs (processes, jobs)
- how to protect applications from one another,
- how to provide fair and efficient access to resources,
- how to operate and control the various I/O devices.
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