单项选择题 Companycom has been performing scheduled backups of their data to tape using "tar" in a script for over one year with no problems. Recently, the tar command is returning a non zero return code during the backup phase, causing the script to fail. What is the primary cause of this problem?（）

单项选择题 A just announced two-port Ethernet card has been installed on a system and it is not recognized. On the HMC the slot shows empty. The device driver has been installed and cfgmgr runs normally. What is the most appropriate action to solve this problem?（）

单项选择题 WhenconfiguringMicro-Partitioningintosharedprocessorpartitions,whatlimitationsshouldbeconsidered?（）