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For the main article about the controller, see Parallel ATA.

The Ultra DMA (Ultra Direct Memory Access, UDMA) interface was the fastest method used to transfer data between the computer (through the ATA controller) and an ATA device until Serial ATA. UDMA took over from Single/Multiword DMA as the choice of interface between ATA devices and the computer. There are 8 different UDMA modes, ranging from 0 to 6 for ATA, 0 to 7 (for CompactFlash), each with its own timing.

Transfer Modes
ModeNumberAlso calledMaximum transfer
rate (MB/s)
Defining standard
Ultra DMA016.7ATA-4
2Ultra ATA/3333.3ATA-4
4Ultra ATA/6666.7ATA-5
5Ultra ATA/100100ATA-6
6Ultra ATA/133133ATA-7
7Ultra ATA/167167CompactFlash 6.0[1]

See also[edit]


  1. ^ CompactFlash 6.0 Introduction