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Whenever a data transfer to or from the managed hardware might be delayed for any reason, the driver writer should implement buffering. Data buffers help to detach data transmission and reception from the write and read system calls, and overall system performance benefits.
A good buffering mechanism leads to interrupt-driven I/O, in which an input buffer is filled at interrupt time and is emptied by processes that read the device; an output buffer is filled by processes that write to the device and is emptied at interrupt time. An example of interrupt-driven output is the implementation of /dev/shortprint.
For interrupt-driven data transfer to happen successfully, the hardware should be able to generate interrupts with the following semantics:
For input, the device interrupts the processor when new data has arrived and is ready to be retrieved by the system processor. The actual actions to perform depend on whether the device uses I/O ports, memory mapping, or DMA.
For output, the device delivers an interrupt either when it is ready to accept new data or to acknowledge a successful data transfer. Memory-mapped and DMA-capable devices usually generate interrupts to tell the system they are done with the buffer.
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List and briefly define three techniques for IO operations?
Blocking IO: The program will pause and wait until the IO operation is complete before resuming. This technique can lead to inefficiency if there are multiple IO operations. Non-blocking IO: The program continues to run while waiting for the IO operation to complete. This allows for better efficiency when handling multiple IO operations simultaneously. Asynchronous IO: The program initiates the IO operation and continues executing, without waiting for the operation to complete. A callback function is usually provided to handle the result once it is available. This allows for better performance in handling large numbers of IO operations.
What is the advantage and disadvantage of interrupt in memory mapped IO?
disadvantages of interrupt
Why is interrupt driven IO better then polling?
Polling checks constantly the status of de I/O device, wasting CPU cycles. However with Interrupt driven I/O the device sends a request to the CPU to indicate that it needs attention. So, in some cases, Interrupt driven I/O will be better than polling, because doesn't waste CPU cycles checking when the device needs attention.
Difference between programmed IO and interrupt IO?
1.Programmed IO is the process of IO instruction written in computer program , where Interrupt Initiated IO is done by using interrupt and some special command. 2.The advantage of Interrupt Initiated IO is ,it is a time consuming process than Programmed IO. 3.In Programmed IO technique to transfer data,required constant motoring on peripheral by CPU,once data transfer is initiated, CPU have to wait for next transfer. In Interrupt Initiated IO once data transfer initiated ,CPU execute next program without wasting time and the interface keep monitoring the device. When the interface determines that the device is ready to transfer data, it generate an interrupt request,CPU stop the current task,execute the transferring process,and then return to the previous on-processing task.
What happens if both CPU and IO devices want to access the bus at the same time?
Maybe you have seen something called an interrupt as you work on your computer. These Interrupt Requests come from processes or devices that want to use resources. It's all very orderly.
Does Jupiter's moon io have oxygen?
There is no significant amount of oxygen on Jupiter.
What is IO mapped?
Peripheral-Mapped IO is IO that is selected when the IO/M- line is high.
What does io mean in English?
If you are referring to the Italian word 'Io' which can be used in the sentence 'Io Sono', Io means I. Io sono means I am.
What is Peripheral-Mapped IO?
Peripheral-Mapped IO is IO that is selected when the IO/M- line is high.
Differentiate between memory mapped IO and IO mapped IO?
Memory mapped IO is one where the processor and the IO device share the same memory location(memory) while IO mapped IO is one where the processor and the IO device have different memory located to each other.
What moon is named io?
The moon Io.
What is the birth name of Io Bottoms?
Io Bottoms's birth name is Io Cecilia Bottoms.
