/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 bYpipelining data transfers and transferring data in sYnchronous (strobed) mode. Developed bYQuantum Corporation, ATA-4 has been freelY licensed to manufacturers and is supported bY {Intel Corporation}. (1998-09-30)