linux - Dual boot and SSD

I've recently bought an SSD to install Linux and a few other things. My current OS is on another SSD and am hoping to use both SSDs at the same time. However, if I do install Linux on my new SSD (as a dual boot) is there any risk of my current OS and a lot of my files being wiped? If so, could I unplug all my hard drives except the new one, install Linux and then plug the rest back in so that both Windows and Linux are bootable?

Answer

If I do install Linux on my new SSD (as a dual boot) is there any risk of my current OS and a lot of my files being wiped?

Depending on how Linux is installed, yes.

That is, Linux has facilities for modifying, deleting and overwriting files and partitions upon installation just like any other OS. However, if you take proper precautions (doing a complete backup/mirror of your current OS installation before trying to install Linux), make sure you familiarize yourself with how Linux names drives and partitions and, finally, install somewhere safe (e.g. your second drive), nothing should be lost except possibly your time.

[C]ould I unplug all my hard drives except the new one, install Linux and then plug the rest back in so that both Windows and Linux are bootable?

Linux has its own boot loader which is what allows dual-booting.

If there is no second drive attached (i.e. the one with a Windows or Mac install), it won't write any boot options for the second OS (you will only get an option to boot Linux).

This can be edited manually later, after install, but it is up to you to do this. If you don't manually do this in this scenario, you won't have any boot options other than Linux. If the hard drive with the original OS is attached during you Linux installation, however, the Linux boot loader should detect the original OS automatically upon install and write the proper entries.

Test Your Distro Before Installing

One thing that I would seriously suggest (besides backing everything up with a mirror image of your hard drive) is test out the Linux distro you want to install as a Live CD first.

I personally have a laptop that newer distros don't support display-wise. If I installed one of many newer versions of Linux on it, the installation would fail to yield a properly bootable system. Live CDs allow you to "test" a distro with your hardware and thus save the hassle of rolling back a failed install, which consists mostly of replacing the bootloader -- assuming nothing was overwritten -- but can be a pain in the posterior.

Live CDs carry no risk of overwriting files whatsoever as long as you only boot them (the entire OS is run off a DVD or from memory). If you decide to use a Live CD to install the OS, which is an option, you should take the precautions already listed. Just make sure to grab a Live CD of the install you will be using -- grabbing an Ubuntu 14.04 or CentOS5 Live CD may not do much good if you plan to install CentOS7.