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In a memory mapped input/output __________(a) the CPU uses polling to watch the control bit constantly, looping to see if a device is ready(b) the CPU writes one data byte to the data register and sets a bit in control register to show that a byte is available(c) the CPU receives an interrupt when the device is ready for the next byte(d) the CPU runs a user written code and does accordinglyI had been asked this question during an interview for a job.My doubt stems from Process Structures in section Distributed Communication of Operating System

Answer»

Correct answer is (b) the CPU writes one data byte to the data REGISTER and SETS a BIT in control register to show that a byte is available

The best explanation: None.



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