Portable VirtualBox: run any OS from a USB stick

With changes to the guest OS it gets better: more can be done relatively native. Have a look at "user mode linux" for a good example of that There were attempts to make this work under Windows but I think those projects died pretty quickly as people just used kernel mode vitualisers instead for efficiency so there wasn't massive interest (cooperative Linux is somewhere between: it works in a similar manner to UML but requires admin access).

[1] http://portableappz.blogspot.com/2012/08/virtualbox-4120-801...

I speak this as the developer of the PortableApps.com Launcher, which I did in NSIS as the launchers already in use were NSIS, and as size matters a lot (that killed things like Python outright, though using the RPython parts of PyPy with the garbage collector ripped out would have worked---I checked it out and was able to successfully compile <100KB executables; D was disqualified for some reason I do not recall, Go for its heavy runtime even after ripping out the Unicode tables, &c.), and as I was not at all comfortable in C or C++ at the time.

I rather suspect that a large part of the reason for the apparently poor language choice is that the people that develop and use such things are strongly predominantly young people who are having to rove from computer to computer; as they get older, they tend to end up with a machine of their own and so no longer need portable apps. I don't any more, for example (and I don't use Windows any more either). The developers of these things are in consequence similarly young and have not yet learned good sense in programming (I include myself in that category, though I reckon the PortableApps.com Launcher to contain best-of-class engineer in the portable software space---five years later, at age 22, I am surprisingly unashamed of it, though now I would write it in Rust; I should try that one of these years).