Added error dialogs to the control panel when it has an issue, instead of just sitting there, and added a read-only checkbox allowing you to mount the file read-only to prevent anything from even trying to write to it. This is useful if you know ahead of time you don't have write access. Unfortunately, I don't know of a good way to determine dynamically if you have write access other than reading a byte and trying to write it back.

I'm starting to think about the interface with the OS. Right now, it doesn't really do well trying to re-mount a disk after you eject it. Part of this is because all the setup is done at driver Open time, and is kind of a one-time setup. The .Sony floppy driver creates the Drive element at driver Open time but marks it as not available. Then on floppy insertion, it marks the disk as available and posts a diskEvt notification. I'm thinking of doing something similar where the driver is Opened by the INIT, which just sets up an unavailable Drive, then the Control Panel would issue Control calls to the driver to inform it to attach to a specific file. I'm not entirely sure how well that'd work, but it's worth some experimenting.