Chapter 5 —
Operating System Upgrade Warning

> > Before doing an installupdate, you must remove all MMS subsets. Beginning with DIGITAL UNIX V4.0, this will be a mandatory requirement imposed by installupdate. Previous versions of installupdate do not mandate the removal of MMS subsets. However, you must do so to ensure the stability of your installation.

> > The reason for this requirement is that several MMS subsets might depend on specific implementation of the DIGITAL UNIX operating system. These pieces of the operating system may change between operating system releases. As a result, these MMS subsets must be replaced if you upgrade your operating system with installupdate.

> > Since many of the MMS pieces depend on all the versions being the same, all the MME subsets must be replaced during an installupdate.

> > Once the installupdate is completed, you must reinstall the MMS subsets so that the correct binaries are installed.

> > Refer to Section 3.2 for instructions on deleting all installed subsets. Make sure that you have Multimedia Services for DIGITAL UNIX available on a distribution media before deleting the subsets and before performing an installupdate. If Multimedia Services for DIGITAL UNIX was factory installed on your machine and you do not have a CD-ROM distribution, you will not be able to reinstall Multimedia Services for DIGITAL UNIXafter the installupdate.

> > Also, before you remove the MME subsets and perform an installupdate, make sure that the version of Multimedia Services for DIGITAL UNIX that you have supports the version of the DIGITAL UNIX operating system to which you are upgrading.