If you have ever used a computer, you have interacted with an operating system (OS). An OS is a software that manages the hardware and software resources of a computer, such as the CPU, memory, disk, network, and peripherals. But how does the OS communicate with these devices? The answer is through controllers. In this article, you will learn what a controller is, what types of controllers exist, and how they work.
A device controller is a hardware component that controls a specific type of device, such as a disk drive, a keyboard, or a printer. A device controller has a set of registers that store data and commands, and a logic circuit that performs the operations. A device controller can also generate interrupts to notify the OS of the completion or failure of an operation.
As fun??es de um controlador de dispositivo incluem a comunica??o com o dispositivo de hardware, a tradu??o de comandos de alto nível do sistema operativo em comandos de baixo nível que o dispositivo possa compreender, a gest?o do fluxo de dados entre o dispositivo e o sistema operativo e o fornecimento de uma interface de software para o sistema operativo interagir com o dispositivo.
Os dispositivos contam com controladores encarregados de coordenar as instru??es do usuário no sistema operacional. Nesse contexto, os controladores s?o componentes de hardware responsáveis por orientar o desempenho da memória e outros elementos, assegurando a execu??o eficiente das atividades principais.
The term "controller" in operating systems generally refers to a component that oversees and manages specific aspects of a computer system, such as storage, input/output operations, memory, or graphics. The exact role and responsibilities of a controller depend on its specific type and the hardware it is associated with.
A controller driver is a software component that interacts with a device controller. A controller driver knows how to read and write the registers of the controller, and how to handle the interrupts. A controller driver is usually part of the OS kernel, and provides a uniform interface for the OS to access different types of devices.
Na informática, a fun??o de um driver de dispositivo ou controlador de dispositivo é aceitar requerimentos abstratos do software independente do dispositivo acima dele e cuidar para que a solicita??o seja executada, permitindo que o software interaja com o dispositivo.
A device file is a special file that represents a device in the OS. A device file has a name, permissions, and a device number that identifies the device controller and the device unit. For example, /dev/sda is a device file that represents the first disk drive in Linux. A device file allows the OS and the user programs to use the standard file operations, such as open, read, write, and close, to access the device.
As fun??es de um arquivo de dispositivo incluem a comunica??o com o dispositivo de hardware, a tradu??o de comandos de alto nível do sistema operativo em comandos de baixo nível que o dispositivo possa compreender, a gest?o do fluxo de dados entre o dispositivo e o sistema operativo e o fornecimento de uma interface de software para o sistema operativo interagir com o dispositivo.
I/O scheduling is the process of deciding the order and timing of the I/O requests sent to a device controller. I/O scheduling aims to optimize the performance and efficiency of the I/O system, by reducing the waiting time, maximizing the throughput, and balancing the load. I/O scheduling can be done by the OS, the controller driver, or the device controller itself, depending on the level of intelligence and autonomy of the controller.
As requests s?o atendidas pelo sistema operacional usando três segmentos simples. Controlador de tráfego de E / S: mantém o controle do status de todos os dispositivos, unidades de controle e canais de comunica??o. Agendador de E / S: executa as políticas usadas pelo sistema operacional para alocar e acessar o dispositivo, unidades de controle e canais de comunica??o. Manipulador de dispositivo de E / S: Atende às interrup??es do dispositivo e lidera a transferência de dados.
DMA (Direct Memory Access) is a technique that allows a device controller to transfer data directly to or from the main memory, without involving the CPU. DMA reduces the CPU overhead and improves the I/O speed. DMA requires a DMA controller, which is a special hardware that can access the memory bus and coordinate with the device controller and the CPU. I/O channels are extensions of the DMA concept, which provide more functionality and flexibility for the I/O system. I/O channels are special processors that can execute I/O programs and handle multiple devices and transfers.
O DMA é uma técnica que permite a transferência direta de dados entre dispositivos de E/S e a memória principal, sem a interven??o da CPU. O canal DMA é um controlador específico que gerencia essas opera??es de transferência de dados. O DMA é útil para acelerar a transferência de grandes volumes de dados, como quando um dispositivo de armazenamento lê ou grava dados na memória.
I/O virtualization is a technique that allows multiple virtual machines (VMs) to share the same physical I/O devices. I/O virtualization requires a hypervisor, which is a software that manages the VMs and their resources. The hypervisor can either emulate the device controllers for each VM, or use hardware-assisted methods to partition and assign the device controllers to different VMs. I/O virtualization improves the resource utilization and scalability of the I/O system.