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I am currently running Windows 8.1 and I was wondering if I am able to install Ubuntu to my external HDD (It already has stuff on it but it still has a lot of space) and swap between the 2 operating systems. If possible when I update Ubuntu and Windows 8.1 will the updates go to the HDD that the OS was installed 2. Also if I can boot ubuntu from a external HDD how do I swap between Windows 8.1 and Ubuntu?

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up vote 3 down vote accepted

If by "swap" you mean booting into the different operating system (OS), then yes, it is entirely possible. Just install Ubuntu on the external hard drive, then ask the bios to boot into the external hard drive by default. Upon installation, Ubuntu will install the Grub (bootloader) that will allow you to choose which operating system to start. If you unplug the external hard drive, it will boot straight into Windows.

To recap:

  1. Install Ubuntu on your external hard drive. It will automatically detect the other drive with Windows on it and set the bootloader accordingly.

  2. Go in your bios and set the boot priority to External hard drive -> Internal HDD

However, if by swap, you mean actively flipping from one OS to the the other, well, you can't do that. It's not just two different programs running at the same time that you can flip between. The operating system (OS) is responsible for the interactions between the hardware pieces of the computer. The OS needs to have full control of the hardware at all times.

If you REALLY want to flip between the two systems, you can use a virtual machine. Basically, you can set, say, Ubuntu, to be able to start Windows inside itself. You would obtain the layers:

Hardware-> Ubuntu -> "faked hardware" -> Windows

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How would i go about booting to a different OS Then After i install it to my Ext HDD? Thanks – Keanu Jan 14 '14 at 23:31
Edited answer, because I realised I answered badly. – morphheus Jan 14 '14 at 23:34
Thanks for the help il get to it : ) – Keanu Jan 14 '14 at 23:35
Before i go. I already have stuff on the Ext HDD i want to use for Ubuntu. I've heard that when i install ubuntu to the HDD it will Erase the files i have on it and it will only have ubuntu. Is this true? – Keanu Jan 14 '14 at 23:38
You will have to partition the drive if you do not want to lose previous files. It would actually be a good idea to do that, since Windows has a hard accessing files in a Linux partition. The Ubuntu installer can take care of the partitioning. But as with anything, make backups before messing with your drives! – morphheus Jan 14 '14 at 23:40

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