{{Short description|Data transfer method for ATA hard drives}} {{For|the main article about the interface|Parallel ATA}} {{refimprove|date=September 2014}}
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.
thumb|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.<ref>[https://archive.org/stream/SCSISpecificationDocumentsATAATAPI/ATA_ATAPI/AT%20Attachment%20with%20Packet%20Interface%20-%207%20Volume%202%20-%20Parallel%20Transport%20Protocols%20and%20Physical%20Interconnect%20%28ATA_ATAPI-7%20V2%29%20Revision%204b#page/n189/mode/2up AT Attachment with Packet Interface - 7 Volume 2 - Parallel Transport Protocols and Physical Interconnect (ATA/ATAPI-7 V2) E.2.1.1 Cabling p172]</ref>
[[File:SANDISK Extreme Pro CompactFlash card 32 GB 90 MBs.jpg|thumb|SanDisk 32 GB CF card supporting VPG20 and UDMA7]] {| class="wikitable" style="text-align:center" |+ Transfer modes ! Mode || Number || Also called || Maximum transfer<br/>rate (MB/s) || Minimum<br/>cycle time || Defining<br/>standard |- | rowspan=8 | Ultra DMA | 0 || || {{0}}16.7|| 120 ns || ATA-4 |- | 1 || || {{0}}25.0|| {{0}}80 ns || ATA-4 |- | 2 ||Ultra ATA/33{{0}}|| {{0}}33.3|| {{0}}60 ns || ATA-4 |- | 3<ref name="80c">80-conductor cable required</ref> || || {{0}}44.4|| {{0}}45 ns || ATA-5 |- | 4<ref name="80c" /> ||Ultra ATA/66{{0}}|| {{0}}66.7|| {{0}}30 ns || ATA-5 |- | 5<ref name="80c" /> ||Ultra ATA/100|| 100{{0|.0}}|| {{0}}20 ns || ATA-6 |- | 6<ref name="80c" /> ||Ultra ATA/133|| 133{{0|.0}}|| {{0}}15 ns || ATA-7 |- | 7 || {{nobr|Ultra ATA/167}} || 167{{0|.0}} || {{0}}12 ns || CompactFlash 6.0<ref>[http://compactflash.org/2010/cf-6-0-introduces-industry-leading-performance-and-feature-enhancements/ 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 }}</ref> |}
== See also == * PIO—The first interface type used between devices (mainly hard disks) and the computer. * Parallel ATA * Serial ATA
==References== <references />
Category:AT Attachment