Tips:  Consider the following points: 

GLYPH<SM590000> If you are defining drives that are installed in a system-managed IBM tape library, such as the TS7700, you must specify LIBRARY=YES . 

GLYPH<SM590000> If more than one IBM Z host is sharing the virtual drives in the TS7700, specify SHAR- ABLE=YES . This specification forces OFFLINE  to YES . It is up to the installation to ensure the correct serialization from all attached hosts. 

GLYPH<SM590000> You must use the composite library ID of the TS7700 in your HCD definitions. 

GLYPH<SM590000> The distributed library IDs are not defined in HCD. 

To define the remaining TS7700 3490E virtual drives, repeat this process for each CU in your implementation plan. 

## 6.2.2 Activating the I/O configuration 

Differences exist in the concurrent input/output definition file (IODF) activation process between a new tape library implementation and a configuration change that is made to a library. Changes to the virtual devices’ address range of a library is an example of where concurrent IODF activation is useful. 

Note:  As an alternative to the procedures that are described next, you can perform an initial program load (IPL) or restart of the system. 

## Installing a new tape library 

If you are installing a TS7700 for the first time, this installation is a new library from a host software definition perspective. When you are activating the IODF for a new tape library, the following steps must be completed to get the tape library or TS7700 online without an IPL of your systems: 

1. Activate the IODF. 

2. Run MVS console command VARY ONLINE  to vary online the devices in the library. This command creates some of the control blocks. You should see the following message: 

IEA437I TAPE LIBRARY DEVICE(ddd), ACTIVATE IODF=xx, IS REQUIRED 

3. Perform the final ACTIVATE. This action is required to build the eligible device table (EDT) for MVS Allocation. 

After activation, you can check the details by using the DEVSERV QTAPE  command. For more information, see 10.1.2, “MVS system commands” on page 593. 

## Modifications to an existing tape library 

When you are modifying a tape library so that device addresses can be changed, complete the following steps: 

1. Activate an IODF that deletes all devices from the library. 

2. Activate an IODF that defines all of the devices of the modified library. 

3. Run MVS console command VARY ONLINE to vary online the devices in the library. This command creates some of the control blocks. You see the following message: 

IEA437I TAPE LIBRARY DEVICE(ddd), ACTIVATE IODF=xx, IS REQUIRED 

4. Perform the final ACTIVATE. 

