Creating an external link

You can create an external link to an MVS data set, and then transparently access the MVS data set by referencing the external link. The external link simulates a UNIX-like hierarchical naming convention for z/OS conventional MVS data sets. This is done using the ln command, for example:

mount mvshost1:USER1 /mnt
mount mvshost1:/hfs/u/nfs /samples
ln -s USER1.MVSFILE /samples/linkfile,"extlink"

In this example a z/OS UNIX file object, /linkfile, of the file type "extlink" is created containing the file name of the MVS data set USER1.MVSFILE to be accessed. The source file must be mounted to a z/OS UNIX file system. The external link must reference an MVS data set. All future references to /samples/linkfile access USER1.MVSFILE transparently.

In this example the file /usr/pub/myfile is copied to the MVS data set USER1.MVSFILE that is contained in the external link /samples/linkfile:

cp /usr/pub/myfile /samples/linkfile

Your installation should make sure that the appropriate security permissions have been obtained to access the MVS data set. You will receive "Permission Denied" message if the mount point /mnt has not been established on USER1.

A mount point must be established before the external link is established. Otherwise, the error code ACCESS DENIED is returned. For physical sequential data sets, the high level qualifier of a data set must be established. For example, if you had a file called smith.test.data you can mount with smith, smith.test, or smith.test.data as your high level qualifier. For PDS and PDSE data sets, the fully qualified name must be established as a mount point. An example of a fully qualified name would be, smith.test.data.