22c0e3c8_pgrade_and_Installation_Manual__Explanation
[Required Information] Optional components and OpenVMS Management Station files [Explanation] 
The upgrade procedure prompts you to specify whether you want to install the library (VMS073.C), optional (VMS073.D) OpenVMS components, and OpenVMS Management Station software PC files (VMS073.F). Appendix D lists the files included in these save sets. You can save some space on your system disk if you choose not to install these components, but be sure to review Appendix D before deciding.
OpenVMS VAX Version 7.3 Upgrade and Installation Manual
Explanation