You should be familar with the library list concept. If not, review topic 3, Library Lists on the tutorial page.

In your library list, the first user library is the current library. The predecessor to the AS/400, the System 38, did not have a current library concept. To allow for this, a special value *CRTDFT is allowed.

The default value of the library parameter of some commands is *CURLIB. For example, if you use the Create Physical File command, CRTPF and do not specify a destination library, the system will create the file in your current library. But, if your current library is defined as *CRTDFT, the system will create the file in QGPL. This library, the "General Purpose Library", is similar to the root directory in a PC. That is, if the system does not know where to put something, it will likely end up here.

System Administrators fight to keep garbage out of QGPL. For many administrators, the G in QGPL stands for Garbage.

Another system supplied library is QTEMP. Every job has its own QTEMP libary. The library gets cleared everytime the job ends. So, this is a great place to put truly temporary files.