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This has the following advantages: - During boot, the BOOT_TIME record is now written right after the file systems become writable, but before users are allowed to log in. This means that they can't cause `hidden logins' by logging in right before init(8) kicks in. - The pututxline(3) function may potentially block on file locking, though this is very rare to occur. By placing it in an rc script, the user can still kill it with ^C if needed. - Most importantly: jails don't use init(8). This means that a force reboot of a system running jails will leave stale entries in the accounting database of the jails individually.