from
The Free On-line Dictionary of Computing (8 July 2008)
ATA-4
UDMA
Ultra-ATA
Ultra DMA
<storage> /ul'tr* D M A/ (Or "Ultra DMA", "UDMA", "Ultra-ATA",
"Ultra-DMA/33") A development of the {Advanced Technology
Attachment} specifications which gives nearly twice the
maximum transfer speed of the {ATA-3} standard ({PIO} Mode 4).
ATA-4 Extensions Ultra DMA/33 Synchronous DMA Mode maximum
burst transfer rates:
Mode Cycle Time Transfer Rate
ns MB/s
0 235 16
1 160 24
2 120 33
This is achieved by improving timing windows in the {protocol}
on the ATA interface; reducing propagation delays by
{pipelining} data transfers and transferring data in
{synchronous} (strobed) mode.
Developed by {Quantum Corporation}, ATA-4 has been freely
licensed to manufacturers and is supported by {Intel
Corporation}.
(1998-09-30)