>Hi Paul,
>
>>You can buy UPS's that have a serial interface on them to notify the server to shutdown. Shutting down the app via a file triggered by this should be a decent solution to the problem.
>
>Have you tested this approach? What do you do with a "slow" user that works to the last second? If the server UPS is ready to go down, it will just close files and be done with it. What happens to your data in this case? I am talking native files here.


No, I've never done this. I was thinking that, if your app "polls" for this file regularly (eg. once a second, for example), it should be able to tell that it needs to close NOW. Assuming the battery backup can give you even just a minute of warning before it runs out of juice, that should be enough time to pop up a message on the user's screen. If they don't close/save what they're working on the app reverts the changes and closes anyway. This, of course, is based on the assumption that the UPS gives you more than a few seconds warning AND the users also have UPS's. If you don't have that kind of time, you just revert and close. Or, if they don't have UPS's, you'll still have problems because they'll leave the files open. I would guess you might have less of a chance of corruption if your server can at least flush its buffers and forceably close your files if there is only a UPS on the server. But, I've never tested this so it's pure speculation on my part.