Ultra_Direct_Memory_Access

UDMA

UDMA

Data transfer method for ATA Hard drives

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

The Ultra DMA (Ultra Direct Memory Access, UDMA) modes were the fastest method used to transfer data through the ATA hard disk interface, usually between the computer and an ATA device. UDMA succeeded Single/Multiword DMA as the interface of choice between ATA devices and the computer. There are eight different UDMA modes, ranging from 0 to 6 for ATA (0 to 7 for CompactFlash), each with its own timing.

80-conductor cable used for modes faster than UDMA 2 on the left compared to a 40-conductor cable

Modes faster than UDMA mode 2 require an 80-conductor cable to reduce data settling times, lower impedance and reduce crosstalk.[1]

More information Mode, Number ...

See also

References

  1. [1]
    AT Attachment with Packet Interface - 7 Volume 2 - Parallel Transport Protocols and Physical Interconnect (ATA/ATAPI-7 V2) E.2.1.1 Cabling p172
  2. [2]
    80-conductor cable required
  3. [3]
    CompactFlash 6.0 Introduction Archived 2010-11-21 at the Wayback Machine
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