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On Friday 07 January 2011 09:47:28 Jörg Schaible wrote: |
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> Hi Dale, |
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> |
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> Dale wrote: |
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> > Jörg Schaible wrote: |
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> >> that approves my tests ... :-/ |
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> >> |
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> >> Had to boot this morning 5 times, since the root device switched |
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> >> arbitrarily between sde3 and sdg3 and I've chosen by bad luck always the |
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> >> wrong one. It seems there is also some timing involved regarding the |
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> >> initialization of the available devices ... sigh. |
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> >> |
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> >> - Jörg |
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> > |
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> > I had to reboot last night and was in my BIOS looking for other things |
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> > but did notice this feature. I have a setting in my BIOS that tells it |
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> > what drive to look for to boot first. It's above the part where you |
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> > tell it to boot CDROM, hard drive, floppy, ZIP and other bootable |
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> > things. You may want to check and see if you have the same thing. Mine |
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> > is called "hard disk boot priority". I'm not sure this will help but it |
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> > couldn't hurt to check I guess. |
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> |
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> The first device to try is my HD and as alternative I can only select the |
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> CD drive anyway (which is deactivated). At boot time I can still switch |
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> into a boot menu of the BIOS to select something else. |
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This will not affect the order the Linux kernel will identify and label the |
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devices. |
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It will only affect where the BIOS will look for boot-code. |
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Simply put, the following happens when a PC boots: |
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1) BIOS goes through its self-check |
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2) BIOS looks for boot-code on the devices it found in the order configured in |
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the BIOS (BIOS -Boot Order) |
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3) BIOS runs boot-code |
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4) boot-code starts the boot-loader (GRUB) |
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5) GRUB loads kernel into memory |
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6) starts kernel |
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7) kernel detects drives and assigns them names in order of finding them |
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At this point, it goes wrong as the drivers are not always identified in the |
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same order. From what it looks like, on the OPs system, the USB-subsystem is |
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scanned before the SATA-controller. |
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The easiest solution to this problem would be to ensure that the USB-subsystem |
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is not scanned before the boot-device is identified by the kernels boot- |
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process. |
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This can be achieved by configuring the USB-mass-storage support as a module. |
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Another option would be to patch the kernel to either support Labels natively |
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or to have it include a "scan harddisks in following order:...." option which |
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lists which harddisk-drivers (sata/ide/usb) are scanned and in which order. |
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-- |
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