You need a HMC if you plan to:

★ Configure and manage logical partitions and partition profiles (selected models can configure LINUX partitions without a HMC).

★ Perform DLPAR (dynamic LPAR) functions.

★ Activate and manage Capacity on Demand resources.

You can also use the HMC to:

★ Perform service functions

★ Manage frames (towers), IOPs and IOAs. * Note that you cannot see below the IOA to the device level.

★ Manage system profiles (yes, you can have more than one!)

★ Power on and power down. The Service Processor is always hot if there is power to the server.

★ Activate and manage Virtualization Engine technologies.

★ 5250 emulation so you can get a console up on a i5/OS partition or a virtual terminal window for AIX or LINUX.