Optical device programming concepts

Read this topic collection for basic concepts of optical device programming. Basic concepts that are described for optical device programming include the i5/OS™ optical storage system, integrated file system, hierarchical file system, and considerations for volumes.

This topic collection describes the interfaces that an application programmer can use to access optical volumes on i5/OS. The proper name for these interfaces is application programming interfaces (APIs). You can use these APIs to perform interface functions with a variety of different file systems, of which the optical file system is one. This topic collection does not include all of the API documentation. It only describes the aspects of API use that are unique to the optical file system. i5/OS optical file systems consist of any data storage system using optical media including CD, DVD, WORM, and Magneto-Optical.

Programmers can use the available APIs to create, access, change, or maintain optical files and directories. The APIs may be used to customize usage of optical support for specific business applications.

You can use both categories of APIs concurrently. For example, an optical file that is opened for reading by one application by using the HFS Open Stream File API can be opened for reading by another application using the Open UNIX-type API.

Because different file systems exist in i5/OS, you must provide some means for the HFS or the integrated file system to differentiate for which file system a call is targeted. This is accomplished by requiring that the first name in the path name parameter be the name of the file system to be called, preceded by a leading slash. In order for the optical file system to be identified as the receiver of a request submitted to the HFS or the integrated file system, the first portion of the path name parameter must be /QOPT. The remaining path elements to follow /QOPT are volume/directory/subdirectory/file. For an example of a path name, see the following:

/QOPT/CD001/Dir1/SubDir1/File

For more information about using integrated file system and HFS APIs, see the APIs topic.

• Integrated file system
  The integrated file system is a part of i5/OS that supports stream input/output and storage management similar to personal computer and UNIX^® operating systems, while providing an integrating structure over all information stored in your server.
• Hierarchical file system (HFS)
  A hierarchical file system (HFS) is a part of the operating system that includes the application programming interface (API) and the underlying file system (optical or otherwise) support.
• Volume, directory, and file considerations
  Several special considerations will make your optical programming easier.