Computer operating system device management involves managing various hardware devices in the computer system, including processors, memory, disk drives, printers, network interfaces, etc.
IO control mode
IO control method refers to the methods and technologies used to control and manage input/output devices in computer systems. It involves how to communicate with the device, transfer data, and
handle the device's input and output operations.
IO control methods can be classified according to the data transmission method and control level. Common IO control methods include:
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Program control mode: In program control mode, the operation of the equipment is directly controlled by the program. The program needs to send specific instructions and parameters to control the input and output operations of the device.
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Interrupt-driven mode: In the interrupt-driven mode, the device will send an interrupt signal to the operating system after completing the operation, and the operating system responds to the device's interrupt request through the interrupt handler. Interrupt handlers are responsible for handling input and output operations on the device.
The interrupt-driven method is a common IO control method, which is used to handle device interrupt requests and perform corresponding processing. Example: Suppose there is a keyboard device connected to a computer system. When the user presses a key on the keyboard, the keyboard sends an interrupt signal to the operating system, indicating that an input event has occurred. The operating system will respond to this interrupt signal immediately and call the corresponding interrupt handler to handle keyboard input. The interrupt handler reads keyboard input data and passes it to the application for processing. Applications can perform actions based on keyboard input they receive, such as displaying characters on the screen or performing specific functions. -
DMA (direct memory access) mode: In DMA mode, the device can directly access system memory without CPU intervention. The device can transfer data directly to memory through the DMA controller, or transfer data directly from memory to the device.
For example, DMA directly controls the copying of files from the hard disk to the memory without the involvement of the CPU. -
Channel mode: Channel mode is an advanced IO control mode that uses a dedicated IO processor (channel) to manage the input and output operations of the device. Channels can work independently of the CPU and can handle IO operations of multiple devices at the same time, improving system throughput.
Channel mode is an advanced IO control method that uses a dedicated IO processor (channel) to manage the input and output operations of the device. Channels can work independently of the CPU and can handle IO operations of multiple devices at the same time, improving system throughput.
Suppose that in a computer system, there are multiple disk drives and a printer that require IO operations. Under the traditional IO control method, the CPU needs to process the IO requests of each device one by one, which may lead to excessive CPU load and low IO efficiency. Using the channel method, a dedicated IO processor (channel) can be introduced, which is responsible for managing and coordinating the input and output operations of the device. Channels can work independently of the CPU, with their own control logic and buffers. It can handle IO requests from multiple devices at the same time without CPU intervention.
5. Caching technology
Caching technology is a technology used to improve the speed and efficiency of data access. It reduces the number of accesses to slow storage, such as a hard drive, by keeping a copy of the most commonly used or recently accessed data in high-speed storage (cache).
In IO control, caching technology can be used in many aspects:
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Data cache: During the data transfer process, cache can be used to temporarily store data. For example, when reading data from disk, a portion of the data can be cached in memory so that it can be retrieved faster on subsequent accesses.
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Write buffer: When writing data, you can use write buffer to improve the efficiency of write operations. Data is first written to a buffer, which then asynchronously writes the data to slow memory. This reduces the number of direct accesses to slow memory.
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Instruction cache: When the CPU executes instructions, the instruction cache can be used to store the most commonly used instructions. This way, when these instructions need to be executed, they can be fetched directly from the cache without having to read the instructions from main memory each time.
By using caching technology, the efficiency and response speed of IO operations can be significantly improved. Caching technology can improve the overall performance of the system by reducing the number of accesses to slow devices. However, caching technology also needs to consider consistency and data consistency issues to ensure that the data in the cache is synchronized with the data in the slow memory.
Spooling (Simultaneous Peripheral Operations On-Line) is a computer technology used to separate input/output (IO) tasks from the main processor to improve system efficiency and concurrency.
The key to understanding spooling technology is to think of it as an IO management technology. Specifically, spooling technology uses an intermediate storage area (called "Spool") to receive and store data that requires IO operations. This data can be print jobs, file transfers, email sendings, etc.
When an application needs to perform an IO operation, it sends the data to the Spool and can immediately continue performing other tasks without waiting for the IO operation to complete. At the same time, a specialized IO processing program (Spooler) is responsible for reading data from the Spool and transferring it to the corresponding IO device for processing, such as printers, disk drives, etc.
By using spooling technology, the main processor can hand over IO tasks to the Spooler for processing without directly participating in IO operations. This can improve the concurrency of the system, allow multiple IO tasks to be performed simultaneously, and reduce the burden on the main processor. At the same time, Spooler can sort and schedule IO tasks as needed to improve the efficiency of overall IO operations.
Spooling technology is usually used in scenarios where a large number of IO tasks need to be processed or where a long wait for IO operations to complete is required. It is widely used in print jobs, file transfers, batch data processing and other fields, and can improve the response speed and overall performance of the system.
Device drivers are software modules in the operating system that are used to manage and control various hardware devices in the computer system. They act as a bridge between the operating system and the hardware device and are responsible for handling the input and output operations of the device.
There are many different types of device drivers, depending on the type of device and operating system involved. Here are some common device drivers:
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Display adapter driver: used to manage and control the display adapter (graphics card), responsible for displaying images and graphics processing.
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Sound card driver: used to manage and control sound card devices, responsible for audio input and output.
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Network adapter driver: used to manage and control network adapters, responsible for network communication and data transmission.
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Printer driver: used to manage and control printer devices, responsible for printing files and images.
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Mouse and keyboard driver: used to manage and control mouse and keyboard devices, responsible for receiving input signals and sending instructions.
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Storage device drivers: including hard disk drivers, optical drive drivers, etc., used to manage and control the read and write operations of storage devices.
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USB driver: used to manage and control the connection and communication of USB devices.
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Touch screen driver: used to manage and control touch screen devices, responsible for receiving and processing touch input.