I have a 1TB external hard drive that I have installed ubuntu 14.04 on, partioned as 150gig for ubuntu and 2gig for swap space. The remaining memory is free. What I am wanting to do is use the remaining 800+gigs for misc files in windows 7 while keeping ubuntu separate. Since the drive is partioned as ext4 file system, windows will not even recognise the drive. Is this possible?
Windows will still recognize the disk drive. It will recognize the partitions you already have on the drive, but will be unable to allow you to do anything with them, or tell you anything about them other than that they're there. You will still be able to partition the remaining space. You can also make a Windows partition in Ubuntu on the drive: How to make a partition windows can read?