Berkeley Software Distribution Research Articles

Mining evolution data of a product family

Diversification of software assets through changing requirements impose a constant challenge on the developers and maintainers of large software systems. Recent research has addressed the mining for data in software repositories of single products ranging from fine- to coarse grained analyses. But so far, little attention has been payed to mining data about the evolution of product families. In this work, we study the evolution and commonalities of three variants of the BSD (Berkeley Software Distribution), a large open source operating system. The research questions we tackle are concerned with how to generate high level views of the system discovering and indicating evolutionary highlights. To process the large amount of data, we extended our previously developed approach for storing release history information to support the analysis of product families. In a case study we apply our approach on data from three different code repositories representing about 8.5GB of data and 10 years of active development.

A method of processing inbound IP packets with a routing table

AbstractAs the Internet continues to spread and equipment performance improves, the typical operation has been to assign multiple Internet Protocol (IP) addresses to one node. At this type of node, whether the node is the destination of the received packet must be efficiently determined. Conventionally, a Berkeley Software Distribution (BSD) system used an algorithm that performs a linear search for the address of the node. As described in this paper, the Widely Integrated Distributed Environment (WIDE) Project conducted R&D on an improved method using a routing table algorithm. Later an original improvement using a hash table was introduced into Internet Protocol Version 4 (IPv4) implementation in NetBSD and BSD/OS. In this paper, we explain these three methods and evaluate their performances using actual equipment. From the evaluation results, a decision method based on the routing table or the hash table is clearly an improvement over the conventional technique based on a linear search. In addition, the performance of the decision method using the routing table algorithm does not degrade even if the number of addresses increases similar to a conventional routing lookup. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(9): 1–8, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10110

A flexible ATM-host interface for XUNET II

An asynchronous transfer mode (ATM)-based host interface for the XUNET II experimental wide area network is described. The interface is flexible, and its software is easy to program and modify. The hardware implementation of the interface, which resembles a conventional single-board computer, and the programming model of the interface are described. The results of performance measurements of the interface taken at a number of levels are presented. Some recently proposed host interface designs that use the criteria of flexibility, simplicity, accessibility, and compatibility with the Berkeley Software Distribution (BSD) socket interface are outlined.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A survey of password mechanisms: Weaknesses and potential improvements. Part 2

While research continues on more sophisticated methods of authentication, password mechanisms remain the predominant method of identifying computer system users. In this paper, the goals of authentication are reviewed, and the strengths and vulnerabilities of password mechanisms are discussed. The 4.3 Berkeley Software Distribution (4.3BSD) version of U NIX is used as a case study throughout the paper. Several recommendations are presented for the improvement of password mechanisms. In particular, a simple extension of the U NIX password system is described that permits the use of pass-phrases.

A survey of password mechanisms: Weaknesses and potential improvements. Part 1

While research continues on more sophisticated methods of authentication, password mechanisms remain the predominant method of identifying computer system users. In this paper, the goals of authentication are reviewed, and the strengths and vulnerabilities of password mechanisms are discussed. The 4.3 Berkeley Software Distribution (4.3BSD) version of U NIX is used as a case study throughout the paper. Several recommendations are presented for the improvement of password mechanisms. In particular, a simple extension of the U NIX password system is described that permits the use of pass-phrases.

4.2BSD and 4.3BSD as examples of the UNIX system

This paper presents an in-depth examination of the 4.2 Berkeley Software Distribution, Virtual VAX-11 Version (4.2BSD), which is a version of the UNIX Time-Sharing System. There are notes throughout on 4.3BSD, the forthcoming system from the University of California at Berkeley. We trace the historical development of the UNIX system from its conception in 1969 until today, and describe the design principles that have guided this development. We then present the internal data structures and algorithms used by the kernel to support the user interface. In particular, we describe process management, memory management, the file system, the I/O system, and communications. These are treated in as much detail as the UNIX licenses will allow. We conclude with a brief description of the user interface and a set of bibliographic notes.