UDMA
（重定向自Ultra DMA）
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 succeeded Single/Multiword DMA as the interface of choice 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.