The "root" (/), QOpenSys, and user-defined file systems (UDFS) in the integrated file system support the *TYPE2 directory format as of OS/400® V5R1.
The *TYPE2 directory format is an enhancement of the original *TYPE1 directory format. *TYPE2 directories have a different internal structure from *TYPE1 directories and provide improved performance and reliability. In addition to improved performance and reliability, new functions such as integrated file system scanning support are only available for objects in *TYPE2 directories. See Scanning support for more information.
Shortly after i5/OS™ V5R3M0 operating system or a later release is installed, the conversion to *TYPE2 directories will automatically begin for any of the file systems which have not yet been converted to support *TYPE2 directories. This conversion should not significantly impact your system activity as it will run in a low priority background job.
If the conversion function has not yet completed, and the system has a normal or abnormal IPL, the conversion function will resume when the IPL is completed. The conversion will restart on every IPL until all eligible file systems have been fully converted.
The file systems that are eligible for this automatic conversion are "root" (/), QOpenSys and the user-defined file systems for ASPs 1 through 32.