UDMA
Data transfer method for ATA Hard drives / From Wikipedia, the free encyclopedia
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.
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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 ...
Mode | Number | Also called | Maximum transfer rate (MB/s) | Minimum cycle time | Defining standard |
---|---|---|---|---|---|
Ultra DMA | 0 | 016.7 | 120 ns | ATA-4 | |
1 | 025.0 | 080 ns | ATA-4 | ||
2 | Ultra ATA/330 | 033.3 | 060 ns | ATA-4 | |
3[2] | 044.4 | 045 ns | ATA-5 | ||
4[2] | Ultra ATA/660 | 066.7 | 030 ns | ATA-5 | |
5[2] | Ultra ATA/100 | 100.0 | 020 ns | ATA-6 | |
6[2] | Ultra ATA/133 | 133.0 | 015 ns | ATA-7 | |
7 | Ultra ATA/167 | 167.0 | 012 ns | CompactFlash 6.0[3] |
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