Dotlock vs Kernel lock
Hi, my mail reader (XFmail) has an option to lock the mail spool with either dotlock or kernel lock. Lately (potato) I have had some problems with XFmail and locking of the spool file. It crashes after the file is locked, and I have to kill the lock process. What is the difference between these two lock methods, and which one would be considered to be most stable? I do also have the option to use both, but why would I want that? TIA //Christian
Re: Dotlock vs Kernel lock
What is the difference between these two lock methods, and which one would be considered to be most stable? I do also have the option to use both, but why would I want that? Kernel locking relies on a flag to the open() command which tells the krnel to reserve the file. dot-locking relises on certain files and special prgorams that eliminate some race conditions. Both are stable in the sense that they work perectly fine so long as your program works. All that is important is that EVERY prorgam that locks a certain file must lock it the same way,or else one program may not realize another program has locked it. Unfortunately, I can think of about 5 different ways of locking a file. Thus it is sometimes difficult to get diverse applications to interact correctly. Apparently, your mailer can compensate for this by locking a file with more than one method. This is probably a Good Idea unles you are certain that your programs all work together. Carl
Re: Dotlock vs Kernel lock
On Wed, Jun 02, 1999 at 10:33:56 -0400, Carl Mummert wrote: Unfortunately, I can think of about 5 different ways of locking a file. For mail programs, this is standardised within Debian (http://www.debian.org/doc/debian-policy/ch5.html#s5.5). They use liblockfile, or implement dot locking themselves. Ray -- UNFAIR Term applied to advantages enjoyed by other people which we tried to cheat them out of and didn't manage. See also DISHONESTY, SNEAKY, UNDERHAND and JUST LUCKY I GUESS. - The Hipcrime Vocab by Chad C. Mulligan
