From: TJ@noneofyour.business   
      
   On 11/18/2012 09:24 PM, Aragorn wrote:   
   > On Monday 19 November 2012 02:12, Adam conveyed the following to   
   > alt.os.linux.mandriva...   
   >   
   >> TJ wrote:   
   >>   
   >>> So I'm going from two IDE drives to a single IDE and a single SATA.   
   >>> Should be interesting to see what kind of hoops I have to go through   
   >>> to get this up and going.   
   >>   
   >> My "test system" from late 2007 came with one internal SATA drive, and   
   >> I added an internal PATA drive.  [...]   
   >   
   > That's a similar setup to what I have here in this machine.  The machine   
   > was shop-assembled (as a promotion campaign) and came with a SATA disk.   
   > However, I asked the guys at the shop to also put in the PATA disk from   
   > my earlier machine - the one that "blew up".   
   >   
   > The BIOS in this machine sees the PATA disk, but does not present it as   
   > a bootable device.  However, strangely enough, when nothing at all is   
   > installed on the SATA drive, or when the SATA drive is failing - as   
   > happened to me a few months after I bought the machine - the BIOS will   
   > continue to boot from the PATA drive instead.   
   >   
   > The PATA disk came from my earlier, failing machine, and therefore it   
   > has (32-bit) PCLinuxOS 2009.2 on it, /with/ a GRUB bootloader.  I have   
   > installed Mageia 1 (64-bit) on the SATA drive, with Mageia's GRUB also   
   > on the SATA drive.  I have also - for the sake of convenience - copied   
   > over the kernels and initrds of PCLinuxOS to the /boot partition on the   
   > SATA and added them to the Mageia bootloader.   
   >   
   > When booting into PCLinuxOS, the PATA disk is listed as /dev/hda and the   
   > SATA disk as /dev/sda.  When booting into Mageia, the SATA disk remains   
   > /dev/sda but the PATA disk becomes /dev/sdb.  There are also /dev/sdc,   
   > /dev/sdd and possibly even /dev/sde, but those are all for the built-in   
   > card reader - which I never use, but anyway - and for USB thumb drives.   
   >   
   > In my experience, when a SATA and a PATA disk exist in the same machine,   
   > any modern kernel will consider the SATA disk to be /dev/sda and the   
   > PATA disk /dev/sdb.  And if I were to put in a SCSI or SAS disk as well   
   > - which would require a separate controller as the motherboard does not   
   > have any of those - then that one would become /dev/sda.   
   >   
   > The kernel seems to have its preferences and generally puts the higher   
   > performing disk [*] before the others, although I cannot say that I have   
   > read any documentation illustrating this, or anything about the   
   > mechanism by which the kernel judges this.  Major and minor numbers on   
   > SAS and SCSI disks are identical, and they possibly also apply to SATA   
   > and USB storage media, and with newer kernels, PATA disks are now also   
   > seen as SCSI disks.  So I don't think it's a matter of major and minor   
   > numbers.  Someone else might be able to shed a light on this.   
   >   
   >   
   > [*] The traditional order of performance is always SAS, SCSI, SATA,   
   >      PATA, USB.  I do not know where Firewire is situated in that order,   
   >      but I reckon it will be _behind_ SCSI.   
   >   
   Oh that sounds like loads of fun. At present, the master PATA drive is   
   the one I'm keeping, and it's labelled sda. The slave drive is the one   
   I'm replacing, sdb. sdb has three partitions, /, /home, and swap, as   
   created by the Mandriva installer when I first got the drive. (I wanted   
   everything on the same disk, so if it failed I could do just what I'm   
   hoping to do now.) sda has a smallish Windows XP partition, and the /,   
   /home, and swap partitions I usually use as a test bed for new releases   
   before installing them for production. (Right now that's the Mageia 2   
   install I'm using.) The drive labels are the same for both Linux systems.   
      
   My plan was to remove the current sdb and put in the SATA drive, with   
   the hope that it wouldn't disturb the workings, including booting, of   
   the stuff on the current sda. From what you're saying, it ain't gonna   
   happen that way. Sigh.   
      
   TJ   
      
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