Recoverable virtual memory refers to regions of a virtual This combination of circumstances is most likely to be found in situations involving the meta-data of storage address space on which transactional guarantees are repositories. Thus RVM can benefit a wide range of offered. This paper describes RVM, an efficient, portable, applications from distributed file systems and databases, to and easily used implementation of recoverable virtual object-oriented repositories, CAD tools, and CASE tools. memory for Unix environments. A unique characteristic RVM can also provide runtime support for persistent of RVM is that it allows independent control over the programming languages. Since RVM allows independent transactional properties of atomicity, permanence, and serializability. This leads to considerable flexibility in the use of RVM, potentially enlarging the range of applications than can benefit from transactions. It also control over the basic transactional properties of atomicity,

Proof-carrying code is a technique that can be used to execute untrusted code safely. A code consumer specifies requirements and safety rules which define the safe behavior of a system, and a code producer packages each program with a formal proof that the program satisfies the requirements. The consumer uses a fast proof validator to check that the proof is correct, and hence the program is safe. In this report, we discuss applications for which proof-carrying code is appropriate, explain the mechanics of proof-carrying code, compare it with other techniques and suggest two research directions for the method.

With large-scale embedded systems, improvement of development efficiency is one of the most important problems. In this paper, we design and implement an embedded operating system, called the Lambda operating system, which improves the maintainability and development efficiency of the operating system. The Lambda operating system employs micro-kernel architecture, which allows the operating system to be easily designed. In addition, we propose a method to improve operating system performance by reconstructing it in implementation. With the method, Lambda is implemented as monolithic kernel. The method allows the operating system to be quickly developed and gives high performance. This paper also shows that the method is useful through implementing a prototype of Lambda and its performance evaluation. 1.

An important trend in operating system development is the restructuring of the traditional monolithic operating system kernel into independent servers running on top of a minimal nucleus or "microkernel". This approach arises out of the need for modularity and flexibility in managing the ever-growing complexity caused by the introduction of new functions and new architectures. In particular, it provides a solid architectural basis for distribution, fault tolerance, and security. Microkernel-based operating systems have been a focus of research for a number of years, and are now beginning to play a role in commercial UNIX Ò systems. The ultimate feasibility of this attractive approach is not yet widely recognised, however. A primary concern is efficiency: can a microkernel-based modular operating system provide performance comparable to that of a monolithic kernel when running on comparable architectures? The elegance and flexibility of the client-server model may exact a cost in mess...

An important trend in operating system development is the restructuring of the traditional monolithic operating system kernel into independent servers running on top of a minimal nucleus or "microkernel". This approach arises out of the need for modularity and flexibility in managing the ever-growing complexity caused by the introduction of new functions and new architectures. In particular, it provides a solid architectural basis for distribution, fault tolerance, and security. Microkernel-based operating systems have been a focus of research for a number of years, and are now beginning to play a role in commercial UNIX Ò systems. The ultimate feasibility of this attractive approach is not yet widely recognised, however. A primary concern is efficiency: can a microkernel-based modular operating system provide performance comparable to that of a monolithic kernel when running on comparable architectures? The elegance and flexibility of the client-server model may exact a cost in mess...