Dual boot- updating a folder from home partition in Dropbox or Ubuntuone?

I would stick with one service, either user Ubuntu One or Dropbox. Honestly I would recommend dropbox, but that is just me. If you want to have both synced and a folder on each system synced then you can use "the linking trick".

In linux:

ln ~/Dropbox/music ~/synced_music
Then add ~/synced_music to Ubuntu One

In Windows:

Your basically going to do the same thing Making links in windows may help.

MKLINK /J Dropbox/music C:\wherever\synced_music

Then link again for the Ubuntu One side
MKLINK /J "Ubuntu One\synced_music" "C:\wherever\synced_music"

Notes
This will keep the files in sync between Ubuntu One, Dropbox, Liunx, and Windows. However this is pretty silly. You would be far better off choosing either Dropbox or Ubuntu One, and just keeping it in sync. I prefer dropbox for my own reasons but Ubuntu One should work just fine. You can use the link trick with just one service. I use it all the time to keep my game saves shared between computers.

Here's how I made Dropbox stay in my windows partition, but sync even when I'm in ubuntu, when I'm using windows/ubuntu dual boot.

Step 0:

Boot into Ubuntu.

Step 1:

Unlink your (Ubuntu) computer from Dropbox (in Ubuntu only).

Step 2:

Go to the Dropbox folder in windows partition. Rename it to dropbox2.

Step 3:

Link your (Ubuntu) computer to Dropbox.

Step 4:

Pause syncing.

Step 5:

Delete the Dropbox folder, and rename dropbox2 to Dropbox.

Step 6:

Resume syncing.

You can use Ubuntu One for Windows. Download it here.

Ubuntu One makes it easy to back up, sync and access your files, folders, photos and music from anywhere. And from Windows as well.

Simply select which folders you want to sync to your personal cloud by adding them to the sync list. Ubuntu One will take care of the rest.

Read How do I setup Ubuntu One on Windows? to find out more.

I think what you are saying is that you want to be able to put your files into the same folder from either system and have them be uploaded to your cloud regardless of which system is running. You can install Ubuntu One on Windows as this answer describes, but syncing the same folder from both systems is a little more difficult.

This would require one of your systems to set up Ubuntu One to sync a folder that is not in your actual home folder for that system (since it would be on the partition for your other system). Unfortunately, the FAQ says this does not work.

However, one thing you could try doing (I haven't done this myself), is keeping your files in the Windows home folder and specially mounting that folder in Ubuntu according to this answer.

How to set up Ubuntu One on both Ubuntu and Windows?

If I am in windows then the music of my home partition will be synced from Ubuntu One. Is that possible?

It is possible! Even more, it is the very principle of cloud synchronization. It is why services like dropbox and Ubuntu One were developed.

In contrast to your tool that allows you to read the data from your ext4 partition, though, cloud synchronizing different thing. In essence, it is serial. Let me explain:

• Computer A (Ubuntu) uploads a file to 'the cloud' when computer A is online.
• Computer B (Windows) downloads that file from 'the cloud' when computer B is online and uploads new files to 'the cloud.'
• When Computer A in online it checks whether it should download new files or upload new ones.
• ...

The cloud is the intermediary. That means that if you choose your files will be on all your computers and on the cloud. Do not think that a service like Ubuntu One or Dropbox actually goes and fetches a file from your other computer or partition, no it retrieves the copy of the file which is in the cloud. That means that all music files you choose will be in the cloud and in your Ubuntu partition and in your Windows partition. Note that this serialization is versatile. You can have both computers open and work on different files and they will sync to both computers.

What should I do?

The easiest thing to do is to install Ubuntu One in Windows (https://one.ubuntu.com/downloads/windows/install/). In Ubuntu it normally comes preinstalled.

1. Make an account on Ubuntu (if you don't have one yet) and select the folders in Ubuntu you want to be part of your cloud.
2. Let Ubuntu One upload your files to the cloud.
3. Install Ubuntu One on your windows boot.
4. Login in with the same account you use on Ubuntu and select the music folder you want to synchronize. That folder will now be put in your Windows User folder.
5. Enjoy.

If you want to synchronize music you might want to buy some extra space for Ubuntu One.

NOTE: Reading your ext4 partition from windows can be dangerous in the sense that malicious windows software could gain access to your ext4 partition.

It is possible on both, Ubuntu One and Dropbox. I have found UbuntuOne some little troubles on Windows, but no problems at all with Drobox, therefore I prefer Dropbox. Choice is up to you.

Negative for the synching is that it cost some time until a big file is synched, or it is not feasible when you are without connection.

I personally defined a separate FAT partition on the HDD for such transfers, which is readable from both systems perfectly. And who cares about user rights on temporary files?

But did you try to run Traktor in Wine? it should work: http://www.native-instruments.com/forum/showthread.php?t=112551 Same with Ableton, it should work: http://appdb.winehq.org/objectManager.php?sClass=application&iId=2113

Give it a try. You can kick Windoze out of your Linux box.