(Or "Ultra DMA", "UDMA", "Ultra-ATA", "Ultra-DMA/33") A development of the Advanced Technology Attachment specifications which gives nearly twice the maximum transfer rate 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.

Last updated: 1998-09-30

Nearby terms:

ATA-2ATA-4Atanasoff-Berry ComputerAtanasoff, John Vincent

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