You can perform installation and recovery procedures by using the primary installation device along with an alternate installation device that you define.
The alternate installation device can be a tape device or an optical device. Some servers, typically with faster devices attached, might see a performance improvement when using an alternate installation device.
If you use an alternate installation device, the system uses the primary installation device to load a small portion of the Licensed Internal Code during an IPL-type D and then continues the installation by using the media in the alternate installation device.
You can use the alternate installation device function for any installation or recovery that requires replacing Licensed Internal Code, the operating system, licensed programs, or data. Some models might require that you set up an alternate installation device and then use the alternate installation device to install the distribution media created by a central site or for recovery using a SAVSYS media volume.
If you use an alternate installation device, you need to ensure that you set up the device and that you enable the device. You also need to have the CD-ROM, DVD-RAM, or tape media that contains the Licensed Internal Code and your save media.