Explain Hand shakingfor the allocation of addresses to memories and input output devices.

Hand shaking: During an ASYNCHRONOUS data transfer is not based upon predetermined timing pattern. This method of data transfer is used while the speed of an I/O device does not match the speed of this microprocessor, and while the timing characteristic of I/O device is not predictable. In this method the status of the I/O device that is whether the device is ready or not, is checked through the microprocessor before the data are transferred. The microprocessor starts the I/O device to get ready and after that continuously checks the status of the I/O device until the I/O device becomes ready to transfer data. While I/O device becomes ready, the microprocessor sends instructions to transfer the data. This mode of data transfer is also termed as handshaking mode of data transfer. The microprocessor issues an initiating signal to the I/O device to prepare. When I/O device becomes ready this sends signals to the processor to indicate as this is ready. These signals are termed as handshake signals.