/dev/sda and /dev/hda

Karl Larsen k5di at zianet.com
Tue Oct 23 23:50:04 UTC 2007


Rick Stevens wrote:
> On Tue, 2007-10-23 at 17:13 -0600, Karl Larsen wrote:
>   
>>     As I have been working with 2 hard drives I have discovered for 
>> certain that both hard drives change to /dev/sda when a partition on 
>> them is booted. It happens that one is found at /dev/sdf and the other 
>> is found at /dev/sdb. This leads to confusion and in my case I am not 
>> sure what to think.
>>
>>     Is this changing the disk drives a feature or is it a bug? If not a 
>> feature I will write a bug soon.
>>
>>     I understand the /dev/hda stays the first hard drive.
>>     
>
> Well, sorta.  Depends on the kernel you're booting.  On earlier kernels
> (pre-F7), IDE drives remained /dev/hdX.  Under F7 and later kernels,
> ALL block storage is treated as SCSI (/dev/sdX) regardless of how it's
> physically connected.  There's no differentiation at that level (there
> is in sysfs, but let's not go there right now).
>
> If you have other devices that were treated as SCSI before (USB, SATA,
> whatever), your IDE stuff now gets added to the mix and the names can
> change.  You also have to remember that grub uses a TOTALLY DIFFERENT
> drive naming convention than a Linux kernel does.
>
> Also note that in the Linux kernels, /dev/sdX refers to the ENTIRE
> drive--not a partition on the drive.  /dev/sda is the first SCSI
> disk (the ENTIRE disk), /dev/sda2 is the second partition on the first
> SCSI disk.
>
> ----------------------------------------------------------------------
> - Rick Stevens, Principal Engineer             rstevens at internap.com -
> - CDN Systems, Internap, Inc.                http://www.internap.com -
> -                                                                    -
> -     If one is what one eats, then I am fast, cheap and greasy!     -
> ----------------------------------------------------------------------
>
>   
    I'm sorry but you are avoiding the question. I say /dev/sdf changes 
to /dev/sda when booted. Is this a feature or a Bug?



-- 

	Karl F. Larsen, AKA K5DI
	Linux User
	#450462   http://counter.li.org.




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