I have a Macbook pro and a 4TB external Hard drive. Now I want to use ubuntu and windows10 running on the external hard drive in a manner where I get 3 TB for random storage purposes and 500 GB for Linux and 500 GB.So I want to know whether I can use a single hard drive to load BOTH windows 10 and ubuntu and still 3TB more space for my use... do I have to partition the hard drive into three different parts.. I need to use virtual box where windows and ubuntu are running on the external drive and I should be able to use the remaining space..thanks in advance.
Virtualbox actually doesn't need a specific file system that you need to format your external HDD. You can just format it as Ubuntu may read the HDD and then simply create a new space on external HDD using Virtualbox's application.
You may format your HDD to HFS, because FAT filesystem has a max space support about 4 GB. You can't store 500 GB virtual disk on this filesystem. However on HFS you can store since it supports large amount of size.