100 \s+2Final Report on Operating Systems Research in the Berkeley UNIX Project\s-2 July 1, 1989 - June 30, 1990 Susan L. Graham Domenico Ferrari Marshall Kirk McKusick Michael J. Karels Keith Sklower

0 .pp During the period of this grant, three major new facilities were added to 4.3BSD. These are the addition of ISO/OSI networking support, a freely redistributable implementation of NFS, and the conversion to and addition of the POSIX.1 facilities. There were numerous other changes made throughout the system. .pp The ISO/OSI Networking consists of a kernel implementation of transport class 4 (TP-4), connectionless networking protocol (CLNP), and 802.3-based link-level support (hardware-compatible with Ethernet). The session and presentation layers are provided outside the kernel by the ISO development environment (ISODE). Included in this development environment are file transfer and management (FTAM), virtual terminals (VT), a directory services implementation (X.500), and miscellaneous other utilities. Regrettably we were not able to complete support for ISO Connection-Oriented Network Service, TP-0. .pp A new virtual filesystem interface has been added to the kernel to support multiple filesystems. Although generally similar to Sun's vnode interface, the Berkeley interface has been structured for more efficient support of filesystems that maintain state (such as the local filesystem). In addition to the local ``fast filesystem'', we have added an implementation of the network filesystem (NFS) that fully interoperates with the NFS shipped by Sun and its licensees. Because our NFS implementation was implemented using only the publicly available NFS specification, it does not require a license from Sun to use in source or binary form. By default it runs over UDP to be compatible with Sun's implementation. However, it can be configured on a per-mount basis to run over TCP. Using TCP allows it to be used quickly and efficiently through gateways and over long-haul networks. We have also added a memory-based filesystem that runs in pageable memory, which allows large temporary filesystems without requiring dedicated physical memory. .pp The disk quota system has been rewritten to support both user and group quotas (simultaneously if desired). Quota expiration is based on time rather than the previous metric of number of logins over quota. This change makes quotas more useful on fileservers onto which users seldom login. .pp During the grant we added most of the interfaces specified in the POSIX.1 system interface standard. The biggest area of change is a new terminal driver. The terminal driver is similar to the System V terminal driver with the addition of the necessary extensions to get the functionality previously available in the 4.3BSD terminal driver. We also added the POSIX job control interface, which is similar to the 4.3BSD job control interface, but adds a security model that was missing in the 4.3BSD job control implementation. Other additions include POSIX signals, FIFO's, and saved user and group identifiers. We have been tracking the POSIX shell and utility work and have included prototypes of many of the proposed utilities. Finally, we have converted about 80% of the libraries and header files to be compliant with ANSI C. .pp Work has also progressed in several other areas. Several important enhancements have been added to the TCP/IP protocols including TCP header prediction and serial line IP (SLIP) with header compression. The routing implementation has been completely rewritten to use a hierarchical routing tree with a mask per route to support the arbitrary levels of routing found in the ISO protocols. The routing table also stores and caches route characteristics to speed the adaptation of the throughput and congestion avoidance algorithms. .pp The Kerberos (version 4) authentication software has been integrated into much of the system (except NFS) to provide the first real network authentication on BSD. .pp The hardware which is now supported includes: .ip \(bu VAX (86x0, 78x, 750, 730; MicroVAX II, 3200/3500/3600; 82x0) .ip \(bu Tahoe (CCI Power 6/32, 6/32SX; Unisys 7000/xx; Harris HCX7, HCX9) .ip \(bu HP 9000/300 series .lp In addition, kernel support for the Intel i386 and many AT-bus peripherals has been added recently. .pp This release includes several important structural kernel changes. The most pervasive change is to eliminate the user structure fields by using a new internal system call convention. We are also reducing the use of other global variables with the intent to eventually eliminate all references to the user area except for the per-process runtime stack. .pp Another major change is the introduction of a new sleep interface that eliminates all non-local goto's (longjmp's) from the kernel. .pp Many data structures that were previously statically allocated are now allocated dynamically. These structures include the mount table, the vnode table, the name cache, and the quota structures. .pp At the end of the project we put together a formal test release of Berkeley UNIX which we called 4.3BSD-Reno. This work included finishing up and documenting the projects that we have done and putting together a coherent test release. .pp We received the very latest version of ISODE, and made sure that it compiled and ran under 4.3BSD-Reno. Because of delays in getting last minutes fixes installed the ISODE was not ready at the time that the 4.3BSD-Reno tape was made and consequently had to be shipped separately. .pp We prepared a mailing to all our licensees notifying them of the availability of the 4.3BSD-Reno test release. Over a hundred requests were received within the first month indicating widespread interest in this work. .pp The project has managed to secure some non-DARPA continuation funding. However, this funding is significantly below our previous funding and as a consequence our group will probably have to be sized down. In particular, our current funding groups are not very interested in ISO development. So, although we have managed to continue our ISO work in the short term, it is not clear how long this effort can be continued. If NIST is still interested in further ISO work, then they should take action to see that it gets done. We are interested in continuing the ISO work; should this be impossible, we recommend that further ISO work start with the 4.3BSD-Reno and ISODE version 6.6 distributions.