If you cannot find double density floppy disks for use with older consoles, there is a workaround.
If you need to format a DD diskette for an Expression (1) console, but do not have a console to do it on (e.g. if you are using ETCEdit) you can format the disk via DOS using the following command/switches:
format a: /T: 80 /N: 9
Do not use this method unless you have to, as the results won't be as predictable as formatting in the console.