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General discussion

UDMA

Nov 10, 2004 9:53AM PST

could somebody tell me what the difference between ATA33 and ATA66 is please? is it the number of connector pins, the number of wires , DMA support or the blue connector? It might just be that I'm thick!

Discussion is locked

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Re: UDMA
Nov 10, 2004 9:59AM PST

It's all on google.com but in short, ATA33 is a SPEED of the clock rate of the data. At 33MHz, the old 40 conductor cables worked fine.

At 66MHz the NEW 80 CONDUCTOR cables were needed to improve the signal quality.

DMA was implemented and kept from long ago so it's not a factor of ATA33/66 speeds.

Bob

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A slight bit more of unneeded info.
Nov 10, 2004 11:37AM PST

They all [ATA 33, 66, 100, 133] use the 40 pin connector but 66 and up requires the 80 conductor cable. Still 40 pin connector but 40 additional ground wires located so as to reduce noise and adjacent wire coupling in the higher speed data transfers.

The cables are wired to automatically make the end connector, blue, the Master if the drive is jumpered as Cable Select. The middle connector is slave when using Cable Select jumpering.

Simply done by having pin 24 connected on the master connector and the mobo connector but no wire connected to pin 24 on the slave connector.

You can still use Master, Slave jumpering and then disregard the Cable select assignments of connectors.