Modern switched networks such as ATM and Myrinet enable low-latency, high-bandwidth communication. This performance has not been realized by current applications, because of the high processing overheads imposed by existing communications software. These overheads are usually not hidden with large packets; most network traffic is small. We have developed Fast Sockets, a local-area communication layer that utilizes a high-performance protocol and exports the Berkeley Sockets programming interface. Fast Sockets realizes round-trip transfer times of 60 microseconds and maximum transfer bandwidth of 33 MB/second between two UltraSPARC 1s connected by a Myrinet network. Fast Sockets obtains performance by collapsing protocol layers, using simple buffer management strategies, and utilizing knowledge of packet destinations for direct transfer into user buffers. Using receive posting, we make the Sockets API a single-copy communications layer and enable regular Sockets programs to exploit the performance of modern networks. Fast Sockets transparently reverts to standard TCP/IP protocols for wide-area communication.

Reflection has emerged as an important technique in the field of programming language design. Some research has also been carried out in the field of operating systems. In contrast, however, there has been little research in the area of reflective distributed systems. This paper presents an analysis of existing work on reflection and argues that reflection can have an important role to play in distributed systems, in general, and middleware platforms, in particular. The paper concludes with some thoughts on the design of reflective middleware platforms.

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“There probably isn’t a ‘best ’ way to build the system, or even any major part of it; much more important is to avoid choosing a terrible way, and to have clear division of responsibilities among the parts. ” – Butler Lampson [33] Operating system code is complex. But, while substantial complexity is inherent to this domain, some complexity is caused by modularity problems. The goal of the work proposed here is to explore aspectoriented programming as a means of making this kind of complexity unnecessary. Towards this end, we need to identify aspects of the system, use the proposed mechanisms of AOP to modularize them, and establish the impact this approach has on the code. 1

This report documents the progress Carnegie Mellon's Mach Group made in research in very large scale operating systems, for the period 1990-1993. Parts of the Mach Operating system have been incorporated in a number of commercial operating systems, including Encore's Multimax, NeXT OS, MachTen for the Macintoshes, Omron's Luna, OSF/1 for the DEC Alpha, and IBM's OS/2 for the RS6000 based machines. This research was sponsored by the Advanced Research Projects Agency, DoD, through ARPA Order 7330, and monitored by the Space and Naval Warfare Systems Command under contract MDA972-90-C-0035. Views and conclusions contained in this document are those of the authors and should not be interpreted as representing official policies, either expressed or implied, of the Advanced Research Projects Agency or the United States Government. 1 Introduction Work on the Mach operating system began in 1985, and throughout the project, research goals have included: . Providing interprocess communicatio...