Wording: Make it more clear and restrict

doc.zih.tu-dresden.de/docs/jobs_and_resources/barnard_test.md

@@ -64,9 +64,9 @@ below. In order to support the data life cycle management, the well-known
 
 ### Workspaces on Barnard
 
-The filesystems `/data/horse` and `/data/walrus` can be accessed via workspaces. Please refer to the
-[workspace page](../../data_lifecycle/workspaces/), if you are not familiar with the workspace
-concept and the corresponding commands.
+The filesystems `/data/horse` and `/data/walrus` can only be accessed via workspaces. Please refer
+to the [workspace page](../../data_lifecycle/workspaces/), if you are not familiar with the
+workspace concept and the corresponding commands.
 
 | Filesystem (use with parameter `--filesystem=<filesystem>`) | Max. Duration in Days | Extensions | Keeptime in Days |
 |:-------------------------------------|---------------:|-----------:|--------:|