Serial ATA and UDMA

[Edward]

Jonathan Rawle wrote:

> I happened to be looking in dmesg and noticed the following:
> 
> SCSI subsystem initialized
> libata version 1.02 loaded.
> ata_piix version 1.02
> PCI: Setting latency timer of device 0000:00:1f.2 to 64
> 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
> ata1: dev 0 cfg 49:2f00 82:346b 83:7f01 84:4003 85:3c68 86:3e01 87:4003
> 88:20ff
> ata1: dev 0 ATA, max UDMA7, 234493056 sectors: lba48
> ata1: dev 0 configured for UDMA/133
> 
> 
> Does this mean that my SATA hard drive is operating at UDMA/133 rather than
> 150? Some sources say that UDMA7=UDMA/133, but some mention UDMA/150. Is
> there such thing as UDMA/150, or is UDMA7 one step up from UDMA/133?
> 
> Could this an issue of my SATA interface not being completely supported?
> It's the onboard controller on an 865PE motherboard.

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?

Regards,
Ed.