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What is DMA transfer in computer architecture?
DMA represents Direct Memory Access. It is a hardware-controlled data transfer method. An external device can control data transfer. The external device creates address and control signals that are needed to control data transfer. External devices also enable peripheral devices to directly access memory.
What are the steps of a DMA transfer?
Steps involved are:
- Bus grant request time.
- Transfer the entire block of data at transfer rate of device because the device is usually slow than the. speed at which the data can be transferred to CPU.
- Release the control of the bus back to CPU. So, total time taken to transfer the N bytes.
What is DMA transfer discuss different types of DMA transfers?
Direct Memory Access (DMA) Modes
| DMA mode | Cycle time | Transfer rate |
|---|---|---|
| Single Word Mode 0 (SDMA-0) | 960 ns | 2.1 MB/s |
| Single Word Mode 1 (SDMA-1) | 480 ns | 4.2 MB/s |
| Single Word Mode 2 (SDMA-2) | 240 ns | 8.3 MB/s |
| Multiword Mode 0 (MDMA-0) | 480 ns | 4.2 MB/s |
What are the uses of DMA transfer?
Direct memory access (DMA) is the process of transferring data without the involvement of the processor itself. It is often used for transferring data to/from input/output devices. A separate DMA controller is required to handle the transfer. The controller notifies the DSP processor that it is ready for a transfer.
Where is DMA used?
Many hardware systems use DMA, including disk drive controllers, graphics cards, network cards and sound cards. DMA is also used for intra-chip data transfer in multi-core processors. Computers that have DMA channels can transfer data to and from devices with much less CPU overhead than computers without DMA channels.
What are benefits of DMA?
Advantages: Transferring the data without the involvement of the processor will speed up the read-write task. DMA reduces the clock cycle requires to read or write a block of data. Implementing DMA also reduces the overhead of the processor.
What are the DMA transfer modes in computer architecture?
Explain the various DMA transfer modes in computer architecture? DMA represents Direct Memory Access. It is a hardware-controlled data transfer method. An external device can control data transfer. The external device creates address and control signals that are needed to control data transfer.
What is DMA (Direct Memory Access)?
DMA represents Direct Memory Access. It is a hardware-controlled data transfer method. An external device can control data transfer. The external device creates address and control signals that are needed to control data transfer. External devices also enable peripheral devices to directly access memory.
What is the importance of DMA in computer architecture?
The most important is the address of I/O device that wants to read or write data. This information is stored in the data register. Transferring the data without the involvement of the processor will speed up the read-write task. DMA reduces the clock cycle requires to read or write a block of data.
How does the DMA controller terminate the transfer of data?
• When the last word of data in the DMA transfer is transferred, the DMA controller informs the termination of the transfer to the CPU by means of the interrupt line.