[BBLISA] Why do Linux rescue CDs make SATA disks look like SCSI ?

[David Allan]

The change causing non-SCSI disks to appear as sdX rather than hdX is not 
distro specific, it's a base kernel change.  With very new kernels, both 
IDE and SATA appear as SCSI disks.  There is some information available 
online as to why this change was made.  For a brief overview, see:

http://kernelnewbies.org/Linux_2_6_19#head-cdcbaa9c1b476decdc064e0a75d23d1328b1ddce

In general, I would use rescue disks from the same distro as the installed 
system.  Having said that, my sysadmin hat is starting to fit poorly as 
I've been a programmer for several years now, so take my advice with a 
grain of salt.

Dave


On Wed, 14 Jan 2009, Brian McAllister wrote:

>
>>>> On 1/14/2009 at 19:22:53 EST, Brian O'Neill wrote:
>
>  > I believe it has been a general push in the latest kernels to totally
>  > abstract the disk controllers as scsi devices. Although there is some
>  > backwards compatibility for purposes of upgrades, new installations
>  > favor the SCSI emulation. Since the Live CDs are generally the latest
>  > kernel and "start fresh" like a new installation, they use this as
>  > well.
>
> It seems to be specific to SATA.  When I boot the RHEL4 CD on a system with
> regular ATA disks, they appear as hdX.
>
> It seems foolish for rescue mode, as there are features of ATA that cannot
> be used through SCSI (such as SMART) that are useful in working with broken
> systems.
>
> ----
> Brian McAllister                                   Senior Software Engineer
> mcallister at mit.edu                      Bates Research & Engineering Center
> (617) 253-9537                                                Middleton, MA
>
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