vfd - the Virtual Floppy Drive
In all these cases you had to get hold of an USB floppy. You had. Because now, you can download vfd from http://chitchat.at.infoseek.co.jp/vmware/vfd.html. It emulates one or two diskette drives with various capacities, does so either as file-based image or as a RamDrive (fast!) - in short words it is as if you had a physical diskette in your system.
Please take notice that these guys worked hard for a free product. Consider making a small donation when you find their software useful.