单项选择题 A System p administrator needs to upgrade a system from AIX 5.2 to AIX 5.3.  Which of the following installation methods would minimize downtime（）

单项选择题 An administrator attempted to run a sar -u report and received the following error： sar： 0551-201 Cannot open /var/adm/sa/sa12.  Which of the following should be scheduled in adm’s crontab to enable sar reporting（）

单项选择题 A banking user with the userid of ’joe’ is unable to rsh from SYSTEMA to SYSTEMB without having to retype their password， but they can rsh from SYSTEMB to SYSTEMA. No other users are experiencing the same issue.  Both systems have a /home/joe/.rhosts file that contain the proper references to the other host. The /home/joe/.rhosts files on both SYSTEMA and SYSTEMB are owned by userid ’joe’.  Which of the following is the most likely cause of this problem（）