How to exit to Grub without rebooting?

Stuggi · 04-27-2009, 02:04 AM

I and my buddy are trying to make a fast-switching dual-boot system for a desktop computer, and we came up with the clever idea that if you could exit to Grub instead of rebooting you could switch to Windows much faster. The problem is that we have trouble finding out if this is even possible, and if so, how to we do it? The ideal thing would be to get Linux to halt/hibernate and then exit to Grub so one could load Windows.

Getting Windows to do the same is going to be the next problem...

syg00 · 04-27-2009, 02:13 AM

Nope - there is no way to return to the loader code. kexec offers that sort of functionality for Linux only, but it actually requires 2 kernel to be loaded (resident) in storage.
No chance for Windoze.

Try running as virtual guests if switching speed is your main concern.

Stuggi · 04-27-2009, 02:27 AM

Well, if we could get linux to fast switch into Windows then that would be a start since Windows would only be used for gaming and such. A reboot before going into Linux would be acceptable.

But these virtual guests, does it support all the hardware stuff needed for directX or such?

syg00 · 04-27-2009, 03:41 PM

Don't know - I don't need it; others will be able to help there. Can't see why not.
Then there's always "wine" - don't know what the performance would be like for gaming, as again I've never used it.

Stuggi · 04-27-2009, 03:59 PM

Okay, hopeflyy we can get this sorted as my friend probably couldn't live without his games...

PTrenholme · 04-27-2009, 04:14 PM

The conceptual problem is that, when you see GRUB, you have not yet "booted" any OS, so talking about "exiting to GRUB instead of rebooting" is almost an oxymoron.

To accomplish your goal of "fast switching," just (as syg00 suggested) run both your OSs as virtual systems on the same box. That way they'd both be running on your hardware, and you could switch between then with whatever "hot key" combination you set up.