求教，为什么我的bdump，和udump，不存在？

Question

SQL> show user
USER is "SYSTEM"
SQL> show parameter dumpNAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
background_core_dump                 string      partial
background_dump_dest                 string      /u01/diag/rdbms/summer/summer/
                                                 trace
core_dump_dest                       string      /u01/diag/rdbms/summer/summer/
                                                 cdump
max_dump_file_size                   string      unlimited
shadow_core_dump                     string      partial
user_dump_dest                       string      /u01/diag/rdbms/summer/summer/
                                                 trace
SQL> 

Answer 1

background_dump_dest                string      /u01/diag/rdbms/summer/summer/ 
                                                trace 
user_dump_dest                      string      /u01/diag/rdbms/summer/summer/ 

Answer 2

SQL> !
[oracle@linux ~]$ cd /u01/diag/rdbms/summer/summer/
[oracle@linux summer]$ ll
total 96
drwxr-x---  2 oracle oinstall  4096 Jul  5 16:54 alert
drwxr-x---  2 oracle oinstall  4096 Jul  5 16:54 cdump
drwxr-x---  2 oracle oinstall  4096 Jul  5 16:54 hm
drwxr-x---  2 oracle oinstall  4096 Jul  5 16:54 incident
drwxr-x---  2 oracle oinstall  4096 Jul  5 16:54 incpkg
drwxr-x---  2 oracle oinstall  4096 Aug  4 16:42 ir
drwxr-x---  2 oracle oinstall  4096 Jul  5 16:54 lck
drwxr-x---  2 oracle oinstall  4096 Jul  5 16:54 metadata
drwxr-x---  2 oracle oinstall  4096 Jul  5 16:54 stage
drwxr-x---  2 oracle oinstall  4096 Jul  5 16:54 sweep
drwxr-x---  2 oracle oinstall 12288 Aug 20 09:12 trace
没有的，求解！大家帮帮忙，谢谢了

Answer 3

drwxr-x---  2 oracle oinstall 12288 Aug 20 09:12 trace 在这个文件夹下
cd /u01/diag/rdbms/summer/summer/ 
cd trace
看看这里面有什么？