What is direct memory access ?

1.	What is direct memory access ?
Answer» Direct memory access: - For bulk transfer to or from IO device the above mentioned techniques might prove inefficient. So DMA process is ideal for transferring huge amount of data. The IO device requests the microprocessor by sending a signal. After receiving this request signal the CPU disconnects itself from memory and IO devices by tristating address, data and control bus. The CPU sends the acknowledge signal to IO device. After this data transfer takes place, and on completion IO device withdraws DMA request.

Answer»

Direct memory access: -

For bulk transfer to or from IO device the above mentioned techniques might prove inefficient. So DMA process is ideal for transferring huge amount of data. The IO device requests the microprocessor by sending a signal. After receiving this request signal the CPU disconnects itself from memory and IO devices by tristating address, data and control bus. The CPU sends the acknowledge signal to IO device. After this data transfer takes place, and on completion IO device withdraws DMA request.

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