Integrated File System Introduction

 

Use QOpenSys

QOpenSys can be accessed through the integrated file system interface using either the OS/400 file server or the integrated file system commands, user displays, and C language APIs.

Case-sensitivity in the QOpenSys file system

Unlike the "root" (/) file system, the QOpenSys file system distinguishes between uppercase or lowercase when searching for object names. For example, a character string supplied in all uppercase characters will not match the same character string in which any of the characters is lowercase.

This case-sensitivity allows you to use duplicate names, provided there is some difference in uppercase and lowercase of the characters making up the name. For example, you can have an object named Payroll, an object named PayRoll, and an object named PAYROLL in the same directory in QOpenSys.

Path names in the QOpenSys file system

• Path names have the following form:

       Directory/Directory/ . . . /Object
  

• Each component of the path name can be up to 255 characters long. The full path name can be up to 16 megabytes long.
• There is no limit to the depth of the directory hierarchy other than program and server space limits.
• The characters in names are converted to UCS2 Level 1 form (for *TYPE1 directories) and UTF-16 (for *TYPE2 directories) when the names are stored (see Name continuity). Refer to *TYPE2 directories for more information about the directory formats.

Links in the QOpenSys file system

Multiple hard links to the same object are allowed in the QOpenSys file system. Symbolic links are fully supported. A symbolic link can be used to link from the QOpenSys file system to an object in another file system.

See Link for a description of links.

Use integrated file system commands and displays in the QOpenSys file system

All of the commands that are listed in Perform operations using CL commands and the displays that are described in Perform operations using iSeries menus and displays can operate on the QOpenSys file system. However, it may not be safe to use these commands in a multi-thread capable process.

Use integrated file system APIs in the QOpenSys file system

All of the C language functions that are listed in Perform operations using APIs can operate on the QOpenSys file system in a threadsafe manner.

Journal object changes in the QOpenSys file system

Objects in the QOpenSys file system can be journaled. The main purpose for journal management is to enable you to recover the changes to an object that have occurred since the object was last saved. For more information on journaling object changes in the QOpenSys file system, see Journaling support for integrated file system objects.

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