chmod & ODM

[chmod]

chmod who=permissions filename

This gives “who” the specified permissions for a given filename.

Who

The “who” is a list of letters that specifies whom you’re going to be giving permissions to. These may be specified in any order.

Letter	Meaning
u	The user who owns the file (this means “you.”)
g	The group the file belongs to.
o	The other users
a	all of the above (an abbreviation for ugo)

Permissions

Of course, the permissions are the same letters that you see in the directory listing:

r	Permission to read the file.
w	Permission to write (or delete) the file.
x	Permission to execute the file, or, in the case of a directory, search it.

ODM Object Data Manager
1)/etc/objrepos  主要是存储不能网络共享的数据。比如：用户设备定义类等等
(2)/usr/lib/objrepos主要是存储可共享，但只能被 AIX 系统共享，并且是只读的数据。
(3)/usr/share/lib/objrepos主要是存储可共享，不依赖于 AIX 的数据
（1）Pd* 文件
这些文件是系统预定义的 objects，不能被修改，在 AIX 系统安装的时候被创建的。
（2）Cu* 文件
这些文件是用户自定义的 objects，可以被修改。
>echo $ODMDIR  -- 系统默认的ODM

DB2-Buffer Pool
Buffer pool page size should be same with table's
DB2_OVERRIDE_BPF
System buffer pools : 16* 4k/8k/16k/32k
Data update:1. exclusive lock and LSN in page header 2. update data page "dirt" 3. unlock 4. flush buffer pool
>db2mtrk -d