Steve Muir

Functional divisions in the Piglet multiprocessor operating system

Abst rac t As multiprocessor computer systems become more commonplace, and peripherals are built with on-board CPUs, we believe that new operating system models are required to make the most efficient use of such systems. At the same time, the role of computers is changing from a computational device to a communications tool, thus emphasising the ability to efficiently support multimedia communication rather than computation alone. These changes prompted the development of Piglet, an asymmetric multiprocessor operating system. Piglet partitions processors into flmctional groups in order to better utilise multiple processors. We describe the implementation of Piglet and show how it can provide efficient multiplexing of shared resources.

Privileged operations in the PlanetLab virtualised environment

Virtualised systems have experienced a resurgence in popularity in recent years, whether used to support multiple OSes running on a users desktop, provide commercial application hosting facilities, or isolate a large number of users from each other in global network testbeds. We also see an increasing level of interest in having entities within these virtualised systems interact with each other, either as peers or as helpers providing a service to clients.Very little work has been previously conducted on how such interaction between virtualised environments can take place. We introduce Proper, a service running on the PlanetLab system, that allows unprivileged entities to access privileged operations in a safe, tightly controlled manner.This paper describes our work designing and implementing Proper, including a discussion of the various architectural decisions made. We describe how implementing such a system in a traditional UNIX environment is non-trivial, and provide a number of examples of how services running on PlanetLab actually use Proper.

Integration of SDR Cellular Basestations into Military Telephone Networks

The Anywave Network-In-a-Box cellular system has been used by military customers to integrate commercial cellular communications into their existing telephone networks. The combination of flexible software with COTS hardware provides a low-cost solution that supports a wide variety of network interfaces. This paper describes the integration of a Network-In-a-Box system into two different military telephone networks, and discusses some of the design and integration challenges faced. A key component of the integrated solution is the Asterisk open-source PBX application. The first case study shows how Asterisk can be easily used to connect the VoIP-based Network-In-a-Box system to a legacy T1 telephone network. The second case study describes how the standard Network-In-a-Box was enhanced with Type 1 secure communication capabilities in order to interconnect a GSM cellular network with a classified VoIP network.

Experiences implementing GSM in RDL (the Vanu Radio Description Language/sup /spl trade//)

RDL is the radio description language being developed at Vanu, Inc. It is a language specialized to the needs of software radios. One important goal for software radio languages is portability, which is the capability to execute a waveform application on hardware platforms from different manufacturers. RDL is designed to improve the portability of waveforms compared to existing approaches such as the JTRS SCA. This paper describes RDL and reports the experience of a team of engineers who used it to implement the physical and link layers of the GSM cellular telephone waveform.

An operating system architecture for network processors

Network devices have become significantly more complex in recent years, with the most sophisticated current devices incorporating one or more general-purpose CPUs as part of their hardware. The need for such processing capability is motivated by the desire to move greater amounts of functionality, of ever-increasing complexity, from the host CPU to the network device itself. A significant challenge in doing so is managing the complexity of the software running on the network device. We believe that the complexity of this software has reached the point where it is now on a par with many general-purpose systems, and thus requires the same management infrastructure - an operating system for network processors. In this paper we describe an architecture for such an OS, presenting the features most relevant to network processors and describing similarities to and differences from a general- purpose OS. We present a prototype implementation using an SMP system as a virtual network processor, and show how our prototype was used to evaluate a novel user-space interface to a network device.