I have been in a situation many times where I need to use my laptop as a charging station for certain devices that I only have a USB cords for, and have to power it up just to charge my other device. Sometimes I have to do this in remote locations, running entirely from my laptop's battery. Now, I know that I can easily make a usb charger from an old cellphone charger for car or wall-socket, but I was wondering if there exists an OS that is so low-powered that it operates solely to make the usb ports of the computer operational for charging other devices. I was thinking something like a bootable flash-drive or cd, that loads once into the ram and then requires no further processing; no keeping time, no internet, no display, no reading from the HDD or CD/DVD. Does this exist? Anything similar? I am not looking for other mobile ways to charge a usb device, I'm only looking for a low-powered distro of some OS (linux, probably), to load for this purpose. Thanks for any help :)