This sounds like a nefarious question but it’s really not. I have a work laptop and I need to get some personal planning done after work tomorrow. Naturally I don’t want to carry 2 laptops or run the laptop on the internal hard drive for personal use, but going back home and out again is very inconvenient. So my question is - would dual booting via an SSD (that I already use on another machine) leave any trace on the internal hard drive?
Honestly, I don’t expect this to ever be a real issue, I doubt anyone will ever check or even care, but I just want to keep my work stuff entirely separate from my personal stuff. So if there’s a fair chance I could muddy the two in any way by doing this, I won’t - but it’s my understanding that dual booting would be more or less adequately secure?
I don’t think this would work; pretty sure windows will freak out if you try to run it from a completely new computer with different hardware. You could set up a Linux live-USB that would allow you to boot into Linux without leaving any traces on the machine, and you could then plug in your drive as an external so you have access to your files. But if you need to actually boot into your personal PC’s Windows install, I think you need to bring it along too :(
Edit: realized you didn’t mention Windows. Not sure if the above also applies to a standard Linux install but my guess would be yes.
I have had Windows work switching between two laptops with very similar (though not identical) hardware, but it is a much bigger dice roll than something like Debian. In general, Linux handles this much better because the vast majority of drivers are open source and included with the mainline kernel, whereas you often need to go hunting down drivers on Windows.
WRT OP: This is definitely something you can do, but you need to pay close attention to how the secondary operating system is set up. You could boot TAILS for instance (or something along those lines). You could set it up to boot from the SSD. You could probably find something that does the job at much lower paranoia levels as long as you understand how it’s configured.
If you need a temporary solution, you could try booting any live-cd Linux distribution. These generally won’t leave any traces on your system as long as the hd filesystems aren’t mounted. They just won’t run as fast from a DVD/thumbdrive as they would from a SSD.