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HDD Data Transfer Protocols

PIO is a method of transferring data between the running software and a peripheral by means of special CPU instructions. The PIO protocol requires a great deal of CPU overhead to transfer the data. As a result of this inefficiency, a system's performance can be significantly decreased.

DMA is a hardware-based feature that allows certain devices to access system memory for reading and/or writing independently of the central processing unit (Multiword DMA and Ultra DMA protocols). This feature also allows CPU to perform other work during the reading and/or writing. 80-pin interface cable is required for Ultra DMA-3 mode and higher.

The throughput of data transfer protocols (MB/s)

PIO-03.3
PIO-15.2
PIO-28.3
PIO-311.1
PIO-416.7
Multiword DMA-04.2
Multiword DMA-113.3
Multiword DMA-216.7
Ultra DMA-016,7
Ultra DMA-125
Ultra DMA-233,3
Ultra DMA-344,4
Ultra DMA-466,7
Ultra DMA-5100
Ultra DMA-6133
SATA-1150
SATA-2300
SATA-3600