2 Report on the Work at the Computer Systems Research Group

This report describes the system and networking research for the \s-1UNIX\s0 project in the Computer Science Division of the University of California, Berkeley, known as the Computer Systems Research Group (\s-1CSRG\s0). \s-1CSRG\s0 includes four full-time research staff (Mike Karels, Keith Bostic, Marc Teitelbaum and Marshall Kirk McKusick), and one three-quarter-time programmer on loan from another group (Keith Sklower). In addition, two full-time administrative and secretarial people handle licensing and software distribution as well as office support. Current funding for \s-1CSRG\s0 is provided by the Open Software Foundation (\s-1OSF\s0), Hewlett-Packard (HP), and Cray Research.

The goal of the \s-1CSRG\s0 project is to use leading edge research ideas in a stable and reliable implementation that solves current problems in operating systems research. The project also includes incorporation of network protocols and other subsystems into the operating system while maintaining consistency with the existing system call interface. The resulting system is widely used by other researchers in operating systems and network protocols. The most recent two releases, \s-14.2BSD\s0 and \s-14.3BSD\s0, provide the core of the standard networking and/or operating system software for nearly all vendors of \s-1UNIX\s0-based workstations and minicomputers. The network support in the current systems released by both \s-1OSF\s0 (\s-1OSF-1\s0) and \s-1AT&T\s0 (System V, Release 4) is based \s-14.3BSD\s0.

\s-1CSRG\s0 anticipates that its next test release, tentatively called ``Networking Distribution, Second Release'', will contain about 85% of our most recent licensed release, \s-14.3BSD\s0-Reno, but will not contain any proprietary code and hence will be available without any licenses. The only restriction on use or redistribution of this release is a requirement that due credit be given to the Regents of the University of California and its contributors (except for the GNU software, currently the compiler and debugger, that have more stringent release requirements).

The next major release, tentatively called \s-14.4BSD\s0, will be completed and begin shipment in early to mid 1992. We hope that the unencumbering of the source code will be complete and that \s-14.4BSD\s0 will not contain any proprietary code and hence can be made available without any licenses. If the unencumbering is not complete, we will have two distributions. The \s-14.4BSD\s0 distribution will contain the full system and will require an AT&T source license; the unencumbered subset, nicknamed \s-14.4BSD\s0-Lite, will be available without an AT&T license. We expect that \s-14.4BSD\s0-Lite will contain a bootable system and have all the important utilities.

We currently have machine support for 386/486 based PCs and Hewlett-Packard's Motorola 68000 based workstations. We expect support for Sun's Sparcstations. We are moderately confident of having support for Hewlett-Packard's new Snake workstations (HP700 series) Sony's \s-1MIPS\s0 workstations, DEC microvaxes, and DEC's \s-1SPIM\s0 (byte reversed \s-1MIPS\s0) workstations.

The system includes a new virtual memory system derived from that of the public domain portion of the Mach operating system from \s-1CMU\s0 and incorporated into \s-14.3BSD\s0 by the University of Utah. The virtual memory system already contains support for multiprocessors. In the future, we will extend this multiprocessor support to the other major kernel subsystems including the networking, filesystem, and terminal handling. The kernel level multiprocessing support will also be exported from the kernel through the P1003.4a multiprocessing interface to user programs that wish to exploit it. We expect that the products of this work will become the interfaces and implementations of choice for other operating systems and networking researchers in the near future.

The file system interface has been extended to allow greater flexibility and performance, and a freely redistributable version of \s-1NFS\s0 is included. The new system integrates an implementation of the \s-1ISO OSI\s0 networking protocols into the existing socket interface and internal network architecture. This work will include a revised internal network architecture incorporating the best features of both the existing socket support and the ``streams'' layering of the Ninth Edition research version of \s-1UNIX\s0. Both filesystem and networking interfaces improve on previous work with better support for caching in layered architectures. These caching techniques are based on work done by Van Jacobson at the Lawrence Berkeley Laboratory, and will be fully exploited by the \s-1TCP/IP\s0 networking protocols. The applicability of these techniques in the \s-1OSI\s0 protocol suite will be investigated as well.

The system will also include an \s-1IEEE\s0 P1003.1 \s-1(POSIX)\s0 standard operating system interface integrated with the existing system interface in such a way that both interfaces are fully supported and interoperate fully. We have also been closely tracking the P1003.2 and P1003.2a shell and utility standards, and have been updating our utilities to reflect that proposed standard. If the standard has been ratified by the time that we prepare to ship \s-14.4BSD\s0, we expect to be compliant with it, as well. We have been attending the meetings of several other \s-1POSIX\s0 working groups, including P1003.4 (real-time) P1003.4a (multiprocessing), P1003.8 (networked filesystems), and P1003.12 (networking interfaces). We hope to prototype and eventually incorporate support for these standards as they come into existence.