<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.
<storage> (ATAPI) Part of the EIDE interface that provides additional commands to control a CD-ROM drive or magnetic tape.
<storage, standard> (ATA-2, Enhanced Integrated Drive Electronics, EIDE) A proposed (May 1996 or earlier?) standard from X3T10 (document 948D rev 3) which extends the Advanced Technology Attachment interface while maintaining compatibility with current IBM PC BIOS designs
ATA-2 provides for faster data rates, 32-bit transactions and (in some drives) DMA. Optional support for power saving modes and removable devices is also in the standard.
ATA-2 was developed by Western Digital as "Enhanced Integrated Drive Electronics" (EIDE) around 1994. Marketroids call it "Fast ATA" or "Fast ATA-2".
ATA-2 was followed by ATA-3 and ATA-4 ("Ultra DMA").<architecture> (DMA) A facility of some architectures which allows a peripheral to read and write memory without intervention by the CPU. DMA is a limited form of bus mastering.