Is it possible to have multiple installs of WebSphere existing on the same machine? Installation Manager states that WebSphere is already installed

Answer

• You can install multiple instances of WebSphere Application Server onto a single operating system that uses the same user ID.
• When the customer is installing the WebSphere Application Server, each installation is assigned a "Package Group". 
• To install another instance of WebSphere, you need to assign it a unique "Package Group" name.
• If you are using the Installation Manager GUI, it informs you that another version is already installed, but it also allows it to hit "Continue" to install a second instance.
• The "Package Group" name of the second installation instance of WebSphere is assigned an "_number" at the end. Example

  If the first installation instance of WebSphere has a "Package Group" name of "IBM WebSphere Application Server v85", then the second installation instance of WebSphere has a "Package Group" name of "IBM WebSphere Application Server v85_1"
• You can use the imcl command from <Installation_Manager_Home>/eclipse/tools to see the "Package Group" for each installation:

  imcl listInstalledPackages -verbose -or- imcl listInstallationDirectories -long

  The previous commands provides a listing of the currently installed packages by this Installation Manager. It shows the current "Package Group" value for the current installations.
• If you are using a silent method like imcl command or a response file, installing more instances of WebSphere increments the "Package Group" automatically for each additional installation of the same product with different installation paths.