File close issue windows

Question

We are using File.WriteAllBytes to write data to the disk. But if a reboot happens just about the time when we close the file, windows adds null to the file. This seems to be happening on Windows 7. So once we come back to the file we see nulls in the file. Is there a way to prevent this. Is windows closing it's internal handle after certain time and can this be forced to close immediately ?.

Answer 1

Depending on what behavior you want; you can either put it in a UPS as 0A0D suggested; but in addition you can use Windows' Vista+ Transactional NTFS functionality. This allows you to atomically write to the file system. So in your case; nothing would be written rather than improper data. It isn't directly part of the .NET Framework yet; but there are plenty of managed wrappers to be found online.

Sometimes no data is better than wrong data. When your application starts up again; it can see that the file is missing; it can "continue" from where it left off; depending on what your application does.

Answer 2

Based on your comments, there is no guarantees when writing a file - especially if you lose power during a file write. Your best bet is to put the PC on an Uninterruptable Power Supply. If you are able to create an auto-restore mechanism, like Microsoft Office products, then that would prevent complete loss of data but it won't fix the missing data upon power loss.