After lunch (at a pub), John- Dan Langille ended the confer- find that the paper summaries Mark Garner ([email protected]) ence by giving away books and contained in this overview are gave a presentation about writ- T-shirts. Some books were given extremely brief and are intended ing device drivers in FreeBSD. Of to people chosen randomly [by only to help you identify those course, you can’t learn how to using random() to assign num- papers you would like to read in write device drivers in an hour, bers to all attendees, then sort- full. Those readers interested in a but Garner did a good job of pro- ing] and for various feats. Some- longer summary should refer to viding an overview of the frame- one won a book by spending the Digest of Proceedings that work available. I finally learned over six hours trying to get appears at the end of the work- what has happened to minor de- through Canadian customs. shop proceedings. This digest in- vices (made unnecessary because (There was actually someone cludes a summary of the discus- of devfs). Garner also talked who had spent longer, but he sions that followed each of the about softc, a newer, more effi- had already won a book.) presentations. cient framework for writing de- This overview is based on the vice drivers, about how re- HotMobile 2006: 7th IEEE written notes taken by two stu- sources (memory, IRQs, and Workshop on Mobile Comput- dent volunteers, Tapan Parikh ports) should be handled, and ing Systems and Applications and Alex Varshavsky. They took about bus probing and DMA. excellent notes, although they Chris Buescher and Scott Ullrich Summarized by Maria R. Ebling, did not always know who was discussed the various firewalls Program Chair speaking and my notes were not available in the BSD environ- Like the first WMCSA, the goal always complete. If anything has ment. BSD suffers from an em- of this workshop was to foster been reported in error or omit- barrassment of riches here, and interaction among practitioners ted, the responsibility lies the presenters created a large of mobile computing. In keeping squarely on my shoulders and chart, which you can find in with this goal, we decided to re- not theirs. their slides at pfsense.org/bsdcan/, turn with a small, informal to compare the features of the workshop, one with few papers OPENING DISCUSSION three firewall families, ipfw, ipfil- but significant discussions. We ter, and pf. They went on to ex- accepted just nine papers, but we The workshop’s initial discus- plain the m0n0wall project, a had two significant group discus- sion revolved around the follow- version of FreeBSD stripped sions, two exciting panels, and ing statement: “Resolved: The down for use in firewall appli- an insightful keynote address. mobile phone is the only device ances and controlled completely Approximately 40 people attend- people will carry in the future.” through the use of PHP over a ed the two-day event on April We started by taking a quick Web interface (m0n0wall.ch). 6–7, 2006, at the Semiahmoo Re- straw poll in which only six at- They then described their own sort, Washington, USA. tendees voted in favor of the res- project, pfSense (pfsense.org), To reflect these changes, during olution. After the straw poll, at- where they forked their own ver- the opening remarks the organiz- tendees began discussing the res- sion from m0n0wall because ers announced a name change olution. Each attendee had been they wanted to create a firewall for this workshop. They reported randomly assigned to argue the install that was much more fea- that the workshop will now be Pro position or the Con position. tureful. Whereas m0n0wall is known as HotMobile 2006: The The discussion period started based on FreeBSD 4.1 for its 7th IEEE Workshop on Mobile with small groups of people from faster network performance, Computing Systems and Appli- each position. After about 20 pfSense uses FreeBSD 6.1, which cations. USENIX is an in-cooper- minutes, we then switched to has wireless networking support ation sponsor of this workshop. having all the Pros gather their that FreeBSD 4.1 lacks. PfSense arguments and all the Cons gath- includes networking tools, What follows is an overview of the workshop’s proceedings er their arguments. Again, after such as tcpdump and HSFC traf- about 20 minutes, we opened the fic-shaping, borrowed from summarizing the formal presen- tations, but omitting the discus- floor to debate. Each side had OpenBSD, and uses pf for fire- about 5 minutes to present its wall support, giving it the ability sions that followed. The vast ma- jority of this overview focuses on case and then open discussion to do OS fingerprint–based ensued. It should be noted that, blocking. the presentations that are not represented by papers. You will at times, certain members of the ;LOGIN: AUGUST 2006 HOTMOBI LE 2006 SUMMARI ES 95 groups argued in favor of the op- included nine votes for the Pro which localizes the user by posing side. position. Although one attendee matching the current picture to jokingly noted that this was not the database of preloaded pic- Pro Position a scientifically valid approach, tures. The discussion following Cell phones are already ubiqui- the discussion was interesting this paper focused on a few is- tously deployed. Gartner be- and set the proper tone for the sues: training costs, accuracy, lieves that in 2005 the number workshop: one of interaction and whether the entire system of cell phones sold will have and discussion. can run on the phone. reached 780 million units and Alex Varshavsky then presented that the number will hit 2.6 bil- MOBILE PHONES AS APPLIANCES a paper entitled “Are GSM lion by 2009. Also, in India and Phones the Solution for Localiza- China, cell phones are believed The theme of the first paper ses- tion?” He argued that localiza- to be the primary computing de- sion, chaired by Gaetano Borriel- tion using GSM-based mobile vice. Given such a high penetra- lo, was considering mobile phones may be adequate and tion of mobile phones, applica- phones as appliances. John Bar- sufficient for many interesting tion developers will concentrate ton presented the first paper, en- location-aware applications. The on developing applications for titled “Mobile Phones Will Be- authors show that, with GSM- the phones, especially since come the Primary Personal Com- based fingerprinting, it is possi- computing power and storage puting Devices.” He argued that ble to achieve 2–5m median er- are not an issue. because of increasing storage ror indoors, perform room-level and computing power, mobile localization indoors and achieve Con Position phones will eventually replace 70–200m median error out- Today, people use a variety of PCs. Users will utilize large dis- doors. Moreover, by tracking sig- different devices, including cell plays and input devices available nal stability, it is possible to de- phones, watches, PDAs, MP3 at public places for easier inter- tect places people visit with very players, and laptops. Combining action with their mobile phone. high accuracy. the functionality of all these de- After the talk, John took ques- vices into a single cell phone de- tions from the audience. IS LOCALIZATION A SOLVED PROBLEM? vice, resembling a Swiss army John Davis then presented the knife approach, may result in a second talk, on “Supporting Mo- Following our paper session on device that may do many things, bile Business Workflow with localization, Gaetano Borriello but none of them well. For ex- Commune.” The paper proposes (University of Washington) ample, it is unclear what a user a workflow management system moderated a panel session ex- interface of such a device would for a mobile workforce that uti- ploring the question of whether look like. Because the price of lizes “mini-workflows,” net- localization is a solved problem. single-use devices will go down work-isolated components that Three people sat on the panel: significantly, it may be more ap- can be offloaded onto mobile Dieter Fox (University of Wash- propriate for users to carry spe- clients by leveraging Web ser- ington), Mike Hazas (Lancaster cialized devices that have the vices. University), and Jeff Hightower right form factor and the right (Intel Research Seattle). Gaetano user interface for the task at opened the panel by presenting LOCALIZATION hand (e.g., an iPod). Also, fash- four questions to each of the ion has a say in what devices Natalia Marmasse chaired our panelists and giving them each a people carry with them. For in- chance to respond. stances, some people wear second paper session, on local- watches for reasons that have ization. Nishkam Ravi presented Prefacing his first question with nothing to do with time (e.g., the first paper, entitled “Indoor “Cell phones are the location- esthetics). Localization Using Camera aware platform of choice. We Phones.” He proposed an indoor should focus all our attention on After a lively and interactive dis- localization scheme based on improving location systems on cussion, with various attendees camera phones worn as a pen- phones (accuracy, privacy, per- taking up their assigned position dant by the user. The camera formance, etc.). There are no as well as occasionally arguing phone automatically takes pic- other viable platforms.” Gaetano for the other side, we took an- tures and transmits them over asked, “If it doesn’t work on a other vote. This time the result GPRS to the centralized server, cell phone, why bother?” Dieter 96 ;LO GIN: V OL. 31, NO. 4 responded that it does not matter need to be published on the is- tions are often provided by third because everything can be inte- sue,” asking “Shouldn’t research parties.