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Device Management in Operating System

Device management in an operating system means controlling the Input/Output devices like disk, microphone, keyboard, printer, magnetic tape, USB ports, camcorder, scanner, other accessories, and supporting units like supporting units control channels. A process may require various resources, including main memory, file access, and access to disk drives, and others. If resources are available, they could be allocated, and control returned to the CPU. Otherwise, the procedure would have to be postponed until adequate resources become available. The system has multiple devices, and in order to handle these physical or virtual devices, the operating system requires a separate program known as an ad device controller. It also determines whether the requested device is available.

The fundamentals of I/O devices may be divided into three categories:

1. Boot Device
2. Character Device
3. Network Device

Boot Device

It stores data in fixed-size blocks, each with its unique address. For example- Disks.

Character Device

It transmits or accepts a stream of characters, none of which can be addressed individually. For instance, keyboards, printers, etc.

Network Device

It is used for transmitting the data packets.

Functions of the device management in the operating system

The operating system (OS) handles communication with the devices via their drivers. The OS component gives a uniform interface for accessing devices with various physical features. There are various functions of device management in the operating system. Some of them are as follows:

1. It keeps track of data, status, location, uses, etc. The file system is a term used to define a group of facilities.
2. It enforces the pre-determined policies and decides which process receives the device when and for how long.
3. It improves the performance of specific devices.
4. It monitors the status of every device, including printers, storage drivers, and other devices.
5. It allocates and effectively deallocates the device. De-allocating differentiates the devices at two levels: first, when an I/O command is issued and temporarily freed. Second, when the job is completed, and the device is permanently release

Types of devices

There are three types of Operating system peripheral devices: dedicated, shared, and virtual. These are as follows:

1. Dedicated Device

In device management, some devices are allocated or assigned to only one task at a time until that job releases them. Devices such as plotters, printers, tape drivers, and other similar devices necessitate such an allocation mechanism because it will be inconvenient if multiple people share them simultaneously. The disadvantage of such devices is the inefficiency caused by allocating the device to a single user for the whole duration of task execution, even if the device is not used 100% of the time.

2. Shared Devices

These devices could be assigned to a variety of processes. By interleaving their requests, disk-DASD could be shared by multiple processes simultaneously. The Device Manager carefully controls the interleaving, and pre-determined policies must resolve all difficulties.

3. Virtual Devices

Virtual devices are a hybrid of the two devices, and they are dedicated devices that have been transformed into shared devices. For example, a printer can be transformed into a shareable device by using a spooling program that redirects all print requests to a disk. A print job is not sent directly to the printer; however, it is routed to the disk until it is fully prepared with all of the required sequences and formatting, at which point it is transmitted to the printers. The approach can transform a single printer into numerous virtual printers, improving performance and ease of use.

Features of Device Management

Here, you will learn the features of device management in the operating system. Various features of the device management are as follows:

1. The OS interacts with the device controllers via the device drivers while allocating the device to the multiple processes executing on the system.
2. Device drivers can also be thought of as system software programs that bridge processes and device controllers.
3. The device management function’s other key job is to implement the API.
4. Device drivers are software programs that allow an operating system to control the operation of numerous devices effectively.
5. The device controller used in device management operations mainly contains three registers: command, status, and data.

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