PC power button - Slightly off-topic

OK, now I see how it all fits together.

It seems to me then that AutoEndTask should be the default, but with a fairly long timeout. Shutdowns are either initiated by a user, who can then close the uncooperative process (given a long enough timeout), or they are initiated automatically by something like an UPS shutdown, in which case it's better to kill an uncooperative process and lose its data than to wait for power failure to kill everything.

It's true that NTFS systems seldom get seriously corrupted by unexpected resets - that's the idea of the journal. There's still a bit of a risk, and "small" errors do creep in.

However, I was thinking here that there are windows processes and services that don't save their data and prepare for a controlled stop until the windows gui is shutting down - these have trouble when you reset or power-cycle the system. To take a very simple example, resize the "quick launch" area on the taskbar - the setting is not saved until shutdown, and is lost on a crash. The most serious risk is of course, the registry files. These can be modified at any time, including when the system is otherwise hung on a failing shutdown - unclean shutdowns always risk registry corruption. It's fortunately rare, but a hosed registry is a real pain.

Is that really the tradeoff? Every time my machine has tried to shut down and a hung application won't let it, the rest of the applications still shut down ok. Then the machine waits for me to do something about that last application. What would be lost if the machine shuts down hard? I can't remember the last time I actually lost anything this way.

et

I guess it can happen. But how real a threat is this if everything but one app has shut down?

Rick

Yes, the registry is unfortunate ... not for it's existence, but because it is not ACID. The registry wasn't a bad idea, IMO, but the implementation could have been more robust (like a DBMS).

George

Well, I'm not sure I'd think it was a good idea even if it were robust (ACID, as you say) - but I would certainly dislike it less!

Windows has its advantages and disadvantages compared to alternatives, but IMHO *nix style text configuration files are much better. Even the simplistic ini files that used to be popular with Windows are much better - it was just /so/ much easier to see what was changed, make copies of settings, modify things manually, find out which settings were for which application, etc.

The trouble is that while you have one user-level app that has hung on shutdown, much of the rest of the windows gui, OS tasks, services, etc., are still running - these won't shut down properly until the last user app is closed.

I can't give any meaningful answers as to how much of a risk this is - I haven't seen it happen often enough for sensible statistics, and there could well be "invisible" corruption that has later effects. But I know that problems certainly occur sometimes with a hard reset like this.

It is totally unnecessary, of course - the OS should always be able to kill applications that refuse to die.

The problem is more *why* the app won't shut down - is it simply "busy" and will shut down gracefully if given more time, or is it really stuck? Most IT people err on the side of caution and don't want to kill a process unnecessarily. If you wait long enough, the app itself might produce an error message that tells you what is wrong.

There's a story most database admins have heard: a power failure causes a crash of a high volume server. When the power is restored, the server restarts and the DBMS begins fixing the database, rolling it back to the last checkpoint and reapplying new transactions from its log. After a while, a manager comes in to find out why the database isn't up and, believing the DBMS is hung, reboots the server. The server restarts and the DBMS begins fixing the database, rolling it back to the last checkpoint and reapplying new transactions from its log. After a while, a manager comes in ...

George

I never believed applications/services should be using the registry for private settings. With the introduction .NET, I think Microsoft finally admitted that most programs should go back to using config files and not store private information in the registry ... but for now we are stuck with a lot of legacy uses.

George