Updated: 03/10/2024 by Computer Hope

Short for Ultra Direct Memory Access, and also called Ultra ATA (Advanced Technology Attachment), UDMA is a standard developed by Quantum and Intel that is twice as fast as the previous DMA (direct memory access) interface. UDMA was 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

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.

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