let’s say I am writing a Ruby on Rails program and while editing a file, the machine blue screened. in this case, how necessary is it to re-scan the whole hard drive if I don’t want my future files to be damaged?
Let’s say if the OS is deleting a tmp file at the moment when my computer crashed, and still have some pointers to some sector on the hard drive. and if my newly created files happen to be in those sector, and next time the OS clean up files again, it may think that the “left-over” sector wasn’t cleaned last time and clean it again, and damaging our source code. (esp with Ruby on Rails, where the source code could be generated by rails and not by us, and we may not know why our rails server doesn’t work, if a file is affected). we can rely on SVN, but what if the file is affected before we check it in?
i think the official answer will be: “always scan the disk after a crash or power outage, for the data and even the space and indicate attempt to fix any bad sector”, but the thing is, nowadays with the hard drive so big, it could take 2 hours to scan everything. And especially at work, we cannot wait for 2 hours if it is the middle of the day.
Does someone know if the modern OS, like XP, Vista, Mac OS, and Linux (when sometimes the power cord was loose and it didn’t shut down properly and just shut down on 0% battery), with these modern OS, are our source code safe? Do they know how to structure to write to sector so that at most it will waste sector instead of overlapping sectors?
With a modern journaling file system (ext3/4, NTFS), the only problem would be that a file could be in a “half-written” state. Obviously scanning is not going to help this (that’s what backups are for). The file system itself could not be corrupted. If you are using something like FAT, then yes, you should worry about this.