The Ultra DMA (Ultra Direct Memory Access, UDMA) modes are the fastest methods used to transfer data through the
ATA hard disk
A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating hard disk drive platter, pla ...
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
CompactFlash (CF) is a flash memory mass storage device used mainly in portable electronic devices. The format was specified and the devices were first manufactured by SanDisk in 1994.
CompactFlash became one of the most successful of the e ...
), 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
In electronics, crosstalk (XT) is a phenomenon by which a signal transmitted on one circuit or channel of a transmission system creates an undesired effect in another circuit or channel. Crosstalk is usually caused by undesired capacitive, ...
.
{, 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
CompactFlash (CF) is a flash memory mass storage device used mainly in portable electronic devices. The format was specified and the devices were first manufactured by SanDisk in 1994.
CompactFlash became one of the most successful of the e ...
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
Parallel ATA (PATA), originally , also known as Integrated Drive Electronics (IDE), is a standard interface designed for IBM PC-compatible computers. It was first developed by Western Digital and Compaq in 1986 for compatible hard drives and C ...
* Serial ATA
SATA (Serial AT Attachment) is a computer bus interface that connects host adapter, host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives. Serial ATA succeeded the earlier Parallel ATA (PAT ...
References
AT Attachment