Messages in this thread | | | Date | Fri, 06 Jul 2007 08:39:28 -0600 | From | Robert Hancock <> | Subject | Re: PATA-disk named sda |
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Christoph Pleger wrote: > Hello, > >>> In the newest Ubuntu Release, my PATA-disk is called sda instead of >>> hda. Is that a general feature in newer kernel versions or is it a >>> special feature in Ubuntu? >> General. SATA and now PATA drives map onto the /dev/sd range as do >> SCSI, USB etc > > It seems to be not that simple, at least not if both the old IDE > interface and the new libata interface are enabled as modules: In my > Ubuntu system, I created two kernel packages (from the same kernel > source and with the same configuration) and installed them. Afterwards, > I re-created the initial ramdisks, one with the Ubuntu feisty utilities > and one with Debian etch utilities. So, I had the same kernel with > different ramdisks. With the Ubuntu ramdisk, my harddrive was named sda, > but with the Debian ramdisk, it was named hda. > > So, the name of the drive can depend on something which happens in the > ramdisk environment. Does anybody know what that is? And is there a > kernel command line parameter which restores the old behaviour? > > And what about hdparm (setting 32bit I/O and multi-sector mode)? Suren > wrote that 32bit I/O makes no sense when using DMA. Maybe that's right, > but it does not correspond with my experiences. At least, I have the > "feeling" that my IDE disks work much faster since I enabled 32bit > support (DMA already was on before).
No, it has absolutely no effect in DMA mode.
Currently the DMA, multi-sector mode, etc. are not controllable with hdparm with libata. libata is designed to use the fastest settings possible by default. In a lot of cases this messing with hdparm was only needed because of stupidity with the old IDE code (like DMA not being automatically enabled if the low-level driver was built modular).
-- Robert Hancock Saskatoon, SK, Canada To email, remove "nospam" from hancockr@nospamshaw.ca Home Page: http://www.roberthancock.com/
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