All library-resident tape volumes used by an SMSplex must be defined in the tape configuration database. This means that cartridge entry must occur on an SMS system. Therefore, all volumes to be used exclusively by SMS, and all volumes to be shared by SMS and a non-MVS platform must be entered on an SMS system. Either the Cartridge Entry Installation Exit or DFSMSrmm may be used to control which cartridges are accepted. Other considerations include:

• If the volumes already contain useful data, they should be assigned the private volume use attribute.
• If the volumes do not contain useful data and they are to be written on the non-MVS platform, they should be assigned the private volume use attribute to prevent their use as scratch volumes by SMS.
• If the volumes do not contain useful data and they are to be written on the SMS system, they may be assigned the scratch volume use attribute.
• All references to the volumes from a non-MVS platform should be specific volume serial number references.
• Private volumes should be returned to scratch only on an SMS system.
• An attempt to mount a volume on one platform will fail if the volume is already in use on another platform.
• Cartridges should be ejected only from an SMS system.