Proceedings of the ACM SIGOPS 22nd symposium on Operating systems principles

Welcome to the Proceedings of the 22nd ACM Symposium on Operating Systems Principles -- SOSP'09, held in Big Sky, Montana. The 23 papers published here explore a wide range of computer systems topics, from operating system device driver design to system designs for improved security and scalability. Collectively these papers report on some of the most creative and thought-provoking ideas in computer systems today. The papers illustrate the increasing international character of operating research, with co-authors from institutions in 8 different countries represented among the 23 accepted papers. All accepted papers were shepherded by PC members to ensure that they are as complete and easy to read as possible. We hope you will enjoy these papers as much as we did in selecting them. Foremost, we would like to thank the authors of the 139 submitted papers, both those selected and those not, for choosing SOSP as the venue to submit their work. The success of the conference rests on the effort and creativity of its authors. Selecting 23 papers out of the set of submitted papers was difficult because so many of the submissions were of high quality. To make the selection process as fair and as consistent as possible, we used the same reviewing structure as SOSP'07 and other recent systems conferences, with 13 "heavy"-load and 20 "light"-load program committee members. The heavy-load members reviewed about 35 submissions each and attended the face-to-face PC meeting in Seattle, Washington. The light-load members reviewed about 15 papers each and did not attend the PC meeting. With a three-stage reviewing process involving 758 separate reviews, all papers following the submission guidelines received at least three reviews, and some papers received as many as ten. Throughout the process anonymity was maintained, and conflicts of interest precluded, by removing authors or those with direct association with an author from the discussion. In the final selection, 10 of the accepted papers were co-authored by PC members. We would like to take this opportunity to thank the program committee members, and the external reviewers, for their dedication and hard work. We introduced one innovation in the program committee discussion. Based on a recent suggestion made by JD Douceur, we asked each PC member to rank order the papers they reviewed, prior to the PC meeting. We then computed a global order that (approximately) minimized the aggregate mean square error of the global order with respect to the individual rankings of the PC members. Ranking allowed the PC meeting to focus on those papers for which we lacked consensus, and most of the PC felt the ranking data was helpful. The calculated global rank in the end predicted 17 of the 23 papers that were selected for the conference. We notified selected authors as to the rank of their papers, but we chose not to publish the rank for wider dissemination. We collected some additional statistics of interest. Authors of selected papers reported that their projects took a median of four person-years of effort, suggesting that the typical SOSP paper represents ambitious, difficult work. Eight of the 23 selected papers were co-authored by a researcher at Microsoft, but it is also important to note that Microsoft co-authors submitted 31 papers. Authors could "opt-in" to allow their papers to be reviewed by a shadow PC consisting of graduate students at various schools. The shadow PC was run independently, and the regular PC was not allowed to see the shadow PC reviews. Nevertheless, papers where authors allowed shadow PC access, presumably reflecting that the authors believed the paper was ready for wider review, were roughly twice as likely to be selected for publication by the regular PC (17 accepted out of 81 marked as reviewable). In the other direction, a significant fraction of submitted papers (30) ignored the formatting guidelines (e.g. length restrictions), presumably because of haste in preparing the paper under a deadline. Papers that ignored the formatting guidelines were roughly half as likely to be selected as those that followed the guidelines. The Women's Workshop organized for the 20th anniversary of the SYSTERS group and held before SOSP 2007 was a great success. Building on this foundation, a new workshop, Diversity, was organized and co-located with OSDI 2008. Diversity expands on the outreach and mentoring goals of the original Women's Workshop by including topics of interest to both women and to underrepresented minorities. The second offering of this Diversity workshop will be held at this year's SOSP, cementing what we hope will be an annual workshop alternating between OSDI and SOSP. Diversity is one of nine co-located workshops at this SOSP. This will be the first SOSP to offer such a full slate of workshops. Six of the workshops will be held on the Saturday and Sunday before SOSP and three will be held after SOSP on Wednesday afternoon and evening. To maintain the single track tradition of SOSP, no workshop activities overlap with regular conference events. We would like to thank the organizers and sponsors of all nine workshops as well as Marc Fiuczynski, who served as our first Workshop Chair. We welcome community feedback on the addition of a workshop program to future SOSPs.