The earliest PA-RISC servers have proprietary HP devices attached to proprietary HP bus architectures. The T600 is unlikely to ever be supported. The D, K and R class machines are at least partially supported. Support for L3000, N class, and Superdome will someday follow. Superdome requires some additional VM work which is in progress.
People ask about V-class.
V-class has a very different architecture from other HP machines. See the Server Architecture Reference for details. Inc. All rights reserved.