Serial ATA and UDMA

Jonathan Rawle jr36 at
Wed Jun 30 10:05:52 UTC 2004

Edward wrote:

>> ata1: SATA max UDMA/133 cmd 0xC000 ctl 0xC402 bmdma 0xD000 irq 177
>> ata2: SATA max UDMA/133 cmd 0xC800 ctl 0xCC02 bmdma 0xD008 irq 177

> Jonathan, I'm not sure about the controller itself, but don't forget a
> lot of hard drives are still not really native UDMA/150. A lot are still
> parallel hard disk drive interfaces 'converted' to a SATA interface.
> PATA is currently at a limit of UDMA/133, so that may be what you're
> seeing?

I think you could be right. It's a Samsung drive, but I've read that Seagate
are currently the only ones making a native SATA drive. It's hard to find
out the truth, and isn't it a bit misleading when they all advertise them
as being UDMA/150?

However, I don't think that explains what I'm seeing as ata2 also shows
"SATA max UDMA/133", yet I don't have a device connected to it.


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