Short for Ultra Direct Memory Access, and also called Ultra ATA, UDMA is a standard developed by Quantum and Intel that is twice as fast as the previous DMA interface. UDMA was first introduced in 1998 with the ATA-4 or ATA/ATAPI-4 standard. It can transfer data at 33.3 MBps, which is how the UDMA/33 or Ultra DMA/33 names were created. Since its initial release and the approval of new ATA standards, the below UDMA standards are available.

  • ATA-5 – UDMA/66, Ultra DMA/66
  • ATA-6 – UDMA/100, Ultra DMA/100

ATA, Computer acronyms, DMA, Hard drive terms, Hardware terms

UDMA/66 and higher are only supported when an 80-wire 40-pin cable is being used. This cable can be distinguished by looking at the ribbon and noticing the amount of wires compared to a 40-wire cable.

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