-option may be used to mark the new bad sectors as ``bad.''
-\fBNOTE: this can be done safely only when there is no other disk activity\fP,
-preferably while running single-user.
-This option is required unless
+option may be used to mark the new bad sectors as ``bad''
+by reformatting them as unusable sectors.
+This option is required unless the sectors have already been marked bad,
+or the system will not be notified that it should use the replacement sector.
+This option may be used while running multiuser; it is no longer necessary
+to perform format operations while running single-user.
+.PP
+It is no longer necessary to reboot to allow the kernel
+to reread the bad-sector table from the drive.