Palacios 1.2 and Kitten 1.2.0 Released The V3VEE Project at Northwestern University and the University of New Mexico, and the Scalable System Software Department at Sandia National Laboratories are pleased to announce the joint release of Palacios 1.2 and Kitten 1.2.0, substantially improved versions of these new open source operating systems. Palacios is a virtual machine monitor (VMM) for modern architectures, while Kitten is a lightweight kernel for high performance computing. The combination of Palacios and Kitten enables applications, whether virtualized or not, to achieve scalable high performance on large machines. On Sandia's Red Storm machine (the 17th fastest supercomputer in the world), Palacios and Kitten can provide a virtualized environment that enables near-native performance and scaling for communication-intensive applications, at scales in excess of 4096 nodes. More broadly, the two operating systems provide an open substrate for virtualization research, development, use, and teaching in computer systems, computer architecture, and high performance computing. Palacios is a "type I", non-paravirtualized VMM that makes extensive use of the virtualization extensions in modern x86 processors, such as AMD's SVM and Intel's VT-x. Palacios can be embedded into existing kernels, including very small kernels. Thus far, Palacios has been embedded into Kitten and the University of Maryland's GeekOS teaching kernel. Compared to 1.2, significant new functionality has been added, including Intel VT-x support, telemetry, virtio devices, passthrough PCI, symbiotic virtualization interfaces, runtime XML-based guest configuration, a KBuild-based compile time configuration framework, a default guest, and an internal sockets API. Enhancements are present throughout the codebase. Currently, Palacios can run on emulated PC hardware, commodity PC hardware, and Cray XT3/4 machines such as Red Storm. Kitten is a lightweight kernel operating system designed to be used on the compute nodes of distributed memory supercomputers. The primary goal of Kitten is to enable supercomputer applications to scale to significantly higher node counts and perform substantially better than is possible with general-purpose compute node operating systems, such as Linux. The design choices in Kitten target scalability (low noise, deterministic behavior) and performance (physically contiguous memory layout, transparent large pages, and novel techniques for taking better advantage of multi-core processors). Currently, Kitten can run on emulated PC hardware, commodity PC hardware, and Cray XT3/4 machines such as Red Storm. The V3VEE Project is a collaboration between Northwestern University and the University of New Mexico, and is supported by the United States National Science Foundation and the Department of Energy. It is a community resource development project that is creating an open source virtual machine monitor framework for modern architectures. The Scalable System Software Department at Sandia National Laboratories is responsible for developing effective systems software for some of the most performance-critical large scale supercomputers in the world. Palacios is BSD-licensed and available from http://v3vee.org. Kitten is GPL-licensed and available from https://software.sandia.gov/trac/kitten. Detailed instructions on how to download, install, build, and use both operating systems are available at http://v3vee.org. The site also includes links to the relevant discussion groups. Community enhancements to both Palacios and Kitten are very much welcomed. --The V3VEE Team --The Kitten Team