External Objects

While aliases cannot cross file pools, external objects can refer to objects in different file pools. An external object is another type of entity managed by SFS, in addition to files and aliases to files. An external object is an SFS directory entry containing the name (called the remote name) of some object. This object may be a file, but does not have to be. Like a file or alias, an external object has a unique name, appears on a FILELIST screen, and can be renamed, relocated and erased (but not locked). Unlike a file or alias, however, the actual data referenced by the remote name in an external object is not managed by your local SFS server. You cannot directly manipulate it. It may reside in another file pool, minidisk or data base. SFS external object support is an application-enabling facility. External objects are intended for CMS applications which have requirements for mapping SFS file IDs to objects outside of the file pool. The meaning of the information stored in an SFS external object is entirely application-defined.

You can create an external object using the DMSCROB routine. You can query the remote name contained in an external object using the DMSQOBJ routine. For more information on DMSCROB and DMSQOBJ, see the z/VM: CMS Callable Services Reference.