The Ultra DMA (Ultra Direct Memory Access, UDMA) modes are the fastest methods used to transfer data through the
ATA hard disk interface, usually between a 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.
Modes faster than UDMA mode 2 require an 80-conductor cable to reduce data
settling times, lower
impedance and reduce
crosstalk.
{, class="wikitable" style="text-align:center"
, + Transfer modes
! Mode , , Number , , Also called , , Maximum transfer
rate (MB/s) , , Minimum
cycle time , , Defining
standard
, -
, rowspan=8 , Ultra DMA
, 0 , , , , 16.7, , 120
ns , ,
ATA-4
, -
, 1 , , , , 25.0, , 80 ns , , ATA-4
, -
, 2 , , Ultra ATA/33, , 33.3, , 60 ns , , ATA-4
, -
, 3
[80-conductor cable required] , , , , 44.4, , 45 ns , ,
ATA-5
, -
, 4
, , Ultra ATA/66, , 66.7, , 30 ns , , ATA-5
, -
, 5
, , Ultra ATA/100, , 100, , 20 ns , ,
ATA-6
, -
, 6
, , Ultra ATA/133, , 133, , 15 ns , ,
ATA-7
, -
, 7 , , , , 167 , , 12 ns , ,
CompactFlash 6.0
CompactFlash 6.0 Introduction
{{Webarchive, url=https://web.archive.org/web/20101121233926/http://compactflash.org/2010/cf-6-0-introduces-industry-leading-performance-and-feature-enhancements/ , date=2010-11-21
See also
* PIO—The first interface type used between devices (mainly hard disks) and the computer.
* Parallel ATA
* Serial ATA
References
AT Attachment