[wplug] help needed to install ubuntu in external USB

[Vikram Sai Balaji]

Thanks smith, you were right about the order of device. i modified the
values during boot time from (hd1,0) to (hd0,0) on the grub in my external
drive. It worked. Just that it takes some time to load.
Almost every hardware is detected properly. i am able to connect to my wifi
and burn cdś / dvdś.



> Message: 12
> Date: Sun, 19 Aug 2007 07:43:02 -0400
> From: "Bryan J. Smith" <b.j.smith at ieee.org>
> Subject: Re: [wplug] help needed to install ubuntu in external USB
>         drive.
> To: General user list < wplug at wplug.org>
> Message-ID:
>         <1187523782.5038.55.camel at portatux64.mobile.smithconcepts.com >
> Content-Type: text/plain
>
> On Sun, 2007-08-19 at 00:21 -0400, Vikram Sai Balaji wrote:
> > I bought a 500GB external usb drive for my hp compaq nc6230 laptop.
> > Partitioned it into multiple partitions. The first partition is 100GB.
> > i tried installing ubuntu 7.04.on the first partition of that disk.
> > While in install i gave "/dev/sdb" in the boot loader section so that
> > i can use my external usb drive in whatever system i want.  When i
> > start with USB external hard disk as primary boot device it showed me
> > Grub with ubuntu generic. but when i choose ubuntu generic or recovery
> > mode to proceed it shows the following error.
> > Error 15: File not Found
> > Press any key to continue...
>
> I assume when you installed Ubuntu, USB was _not_ the first boot device,
> correct?  That means /dev/sdb was _hd1_ from the standpoint of GRUB.
>
> So when you changed the USB device to the first boot device, /dev/sdb
> now became _hd0_.  That's going to cause problems because the mappings
> must match.
>
> GRUB is going, "there is no hd1" or "/dev/sdb is not hd1".  That is
> because you changed the BIOS disk mapping when you selected USB to be
> the primary boot.
>
> [ SIDE NOTE:  I assume you're used to doing this with Windows, correct?
> You see, Windows (at least DOS-based, although NT-based has limitations
> too) has problems booting when it's not on the "first disk" from the
> standpoint of the BIOS, and needs the the "active" flag set.  Linux does
> not, and can typically boot from any device -- although GRUB will be on
> the first disk, because that's what the BIOS looks for. ]
>
> > title        Ubuntu, kernel 2.6.20-15-generic
> > root        (hd1,0)
>
> Yep, that's your problem.
>
> > # linux installation on /dev/sda1.
> > title        Debian GNU/Linux, kernel 2.6.19 Default (on /dev/sda1)
> > root        (hd0,0)
>
> And Debian is your /dev/sda and normal boot, correct?
>
> > Can anyone help me fix this issue?
>
> Yes, either:
>
> A)  Use the Debian GRUB to chainload /dev/sdb's GRUB, *OR*
> B)  Replace all hd1 with hd0 for Ubuntu's GRUB
>
> If you choose "A" you can boot _either_ Debian or Ubuntu, with_out_
> having to go into the BIOS.  Just add this line to the Debian's
> (/dev/sda) GRUB:
>
>   title Ubuntu /dev/sdb (menu)
>         rootnoverify (hd1,0)
>         chainloader +1
>
> If you choose "B" you'll still have to go into the BIOS and change it
> whenever you want to boot Ubuntu.  Again, when you change USB to boot
> first, your USB device (/dev/sdb) now becomes "hd0".  You'll want to
> change your device mappings in GRUB as well ...
>
>   (hd0)   /dev/sdb
>   (hd1)   /dev/sda
>
> For "A", they remain the same, as when you installed Ubuntu:
>
>   (hd0)   /dev/sda
>   (hd1)   /dev/sdb
>
>
>
> --
> Bryan J. Smith         Professional, Technical Annoyance
> mailto:b.j.smith at ieee.org   http://thebs413.blogspot.com
> --------------------------------------------------------
>         Fission Power:  An Inconvenient Solution
>
>
>
>
> ------------------------------
>
> Message: 13
> Date: Sun, 19 Aug 2007 07:45:52 -0400
> From: "Bryan J. Smith" <b.j.smith at ieee.org>
> Subject: Re: [wplug] help needed to install ubuntu in external USB
>         drive   (CORRECTION)
> To: General user list < wplug at wplug.org>
> Message-ID:
>         <1187523952.5038.58.camel at portatux64.mobile.smithconcepts.com >
> Content-Type: text/plain
>
> On Sun, 2007-08-19 at 07:43 -0400, Bryan J. Smith wrote:
> > Yes, either:
> > A)  Use the Debian GRUB to chainload /dev/sdb's GRUB, *OR*
> > B)  Replace all hd1 with hd0 for Ubuntu's GRUB
> > If you choose "A" you can boot _either_ Debian or Ubuntu, with_out_
> > having to go into the BIOS.  Just add this line to the Debian's
> > (/dev/sda) GRUB:
> >   title Ubuntu /dev/sdb (menu)
> >         rootnoverify (hd1,0)
> >         chainloader +1
>
> Oops, that should be ...
>
>   title Ubuntu /dev/sdb (menu)
>         rootnoverify (hd1)
>         chainloader +1
>
> Note that it should be "hd1" (2nd disk's 1st cylinder, aka MBR), and not
> "hd1,0" (2nd disk's 1st slice's 1st cylinder, aka first sector in slice)
>
>
> --
> Bryan J. Smith         Professional, Technical Annoyance
> mailto:b.j.smith at ieee.org    http://thebs413.blogspot.com
> --------------------------------------------------------
>         Fission Power:  An Inconvenient Solution
>
>
>
>
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