[ubuntu-uk] Switched hard drives

Andy Watts g7mjv at btinternet.com
Wed Feb 27 14:31:18 GMT 2008

Many many thanks for the information :)

It was humourous and informative..


Andrew Oakley wrote:
> Andy Watts wrote:
>> Chris Rowson wrote:
>>>>>> l have 2 hard drives in my machine, 1 with windows 2k and the other with
>>>>>> Ubuntu on it. l've tried having them both connected to the same ribbon
>>>>>> and rebooting with either of the 2 hard drives powered. Sadly it doesn't
>>>>>> seem to work so l wonder whether there's a solution..Both drives are set
>>>>>> as masters.. l don't want to have both OSs on the same hard drive
> Okay, that tells us what you DON'T want to do. ;-)
> What is it that you DO want to do?
> * Dual boot using separate hard drives?
> * Have removable drives?
> * Something else? What?
> Also... are you using IDE/ATA drives (wide flat ribbon) or SATA (thin 
> cable)?
>>> I'm assuming you've got a boot loader (Windows - NT loader I think? -
>>> or GRUB for Linux) installed on one of the hard drives. You'll need
>>> this on the bootable drive so that your PC knows where the operating
>>> system resides.
> I think Andy might be trying to switch off (electrically) one or other 
> IDE hard drives... if so, a boot loader on only one of those drives 
> won't help.
> I suspect Andy is fundamentally misunderstanding the relationship 
> between master/slave and boot options. I suspect Andy thinks a drive has 
> to be master to be bootable (which is incorrect).
>> l did try setting both to masters, installing a switch on the -ve rail 
>> of the 2 molexes. Sadly it didn't work :(
> Yeah, that really won't.
> Why have you set them both as masters on the same cable?
> * You want removable drives (because you're clever, and you might want 
> to move the drive to another PC one day), or you want to be able to 
> entirely switch off a drive (because you're trying to run on the 
> absolute minimum current draw, perhaps because your machine is running 
> from 12V DC battery such as a car or van, or because you're just REALLY 
> stingy with the electricity bill)
> In this case, buy a removable drive caddy or a USB external drive 
> enclosure. Removable caddies are about ten quid and fit into a 5.25" 
> CD/DVD slot.
> (Note that the environmental cost of manufacturing the caddy will vastly 
> exceed the environmental cost of leaving the second drive switched on, 
> in case you think this is some kind of "green" option; unused drives 
> will switch into low-power mode anyway)
> * You want to dual boot in the traditional manner
> Set one as master and put your boot loader on it, such as GRUB. 
> Configure this one boot loader to offer the option to boot off either 
> drive. See the GRUB documentation or ask here for more help configuring 
> GRUB across two drives (clue: HD0, HD1).
> Set the other as slave. You won't need a boot loader on the slave, since 
> the boot loader on the master drive will be able to boot off either 
> drive (and indeed off any other connected bootable device).
> * You want to dual boot through BIOS (because you hate configuring boot 
> loaders, and your BIOS offers a simple boot menu such as Dell's F12 
> option, and you're just a bit awkward like that)
> Set one as master and the other as slave. The BIOS boot options will 
> allow you to boot off drive 0, drive 1 etc.
> Note that this still won't allow you to switch off the unused drive 
> whilst the PC is running. But it will allow you to remove/disconnect the 
>   slave drive (but not the master) once the PC is switched off.
> * You don't want removable drives but you are determined to have two 
> bootable drives that are masters (because both of the hard drives have 
> had their master/slave jumpers permanently forced into the master 
> position in an unfortunate but surprisingly selective accident with a 
> soldering iron / tube of superglue / welding rod, OR, your hard drives 
> are set to master by default and you've lost the jumpers)
> Install the drives on separate cables. Change the jumpers on your CD/DVD 
> drive to be a slave.
> (I have some spare hard drive jumpers if you want one? Send an SAE to A 
> Oakley, 7 Frampton Cottages, GL20 8NX)

More information about the ubuntu-uk mailing list