I am going to do some typing for a friend in her house on an Apple Mac which is probably at least 4-5 years old. (I've never used a Mac.) My question concerns sharing portable discs between pcs and Macs, please. If I save my work to a portable disc on her Mac, will I be able to read/write/edit it on our XP or Vista pc? Likewise, if I'm allowed to bring some of the work home, to continue typing, and then save it to a portable disc on our pc, will it be readable/writable on her Mac? Should I format a disc on any particular machine to make them readable and writable by all of them? I'd appreciate your advice, please. Thanks!