ATA-4

storage /ul'tr* D M A/ (Or "Ultra DMA", "UDMA", "Ultra-ATA",

"Ultra-DMA/33") A development of the Advanced TechnologyAttachment 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 IntelCorporation.

(1998-09-30)