RISKS-LIST: Risks-Forum Digest Weds 29 December 2010 Volume 26 : Issue 26 ACM FORUM ON RISKS TO THE PUBLIC IN COMPUTERS AND RELATED SYSTEMS (comp.risks) Peter G. Neumann, moderator, chmn ACM Committee on Computers and Public Policy ***** See last item for further information, disclaimers, caveats, etc. ***** This issue is archived at <http://www.risks.org> as <http://catless.ncl.ac.uk/Risks/26.26.html> The current issue can be found at <http://www.csl.sri.com/users/risko/risks.txt> Contents: [Backlogged.] Radiation Machines Overdosing Again (Peter Bernard Ladkin) How medical radiation mistakes happened (Jeremy Epstein) UAVs needed encryption (John Long) FCC Acts to Preserve Internet Freedom and Openness (Monty Solomon) Technolog - Hackers steal Walgreens e-mail list, attack consumers (Monty Solomon) Risks of incomplete online archives (Thomas Wicklund) Cell phone "emergency mode" *preventing* 911 call (Joe Thompson) China's MIIT Declares Most VOIP Services, Including Skype, Illegal (Lauren Weinstein) Google Maps vs. USPS in Wisconsin (Richard S. Russell) Gadgets Bring New Opportunities for Hackers (Matthew Kruk) Risk Assessment and Failure Analysis ... (Rob Slade) Abridged info on RISKS (comp.risks) ---------------------------------------------------------------------- Date: Wed, 29 Dec 2010 08:06:25 +0100 From: Peter Bernard Ladkin <ladkin_at_private-bielefeld.de> Subject: Radiation Machines Overdosing Again There is an article in *The NYT* today (29 Dec 2010) about machines made by Varian Medical Systems, which deliver so-called stereotactic radiosurgery, SRS. Patients have been overdosed. The article says that ``according to records and interviews, the SRS unit at Evanston lacked certain safety features, including those that might have prevented radiation from leaking outside the cone.'' Some cases have been put down to `operator error': ``In Missouri, for example, 76 patients were overradiated because a medical physicist did not realize that the smaller radiation beam used in radiosurgery had to be calibrated differently than the larger beam used for more traditional radiation therapy.'' The article is available to registered users of the NYT WWW site at http://www.nytimes.com/2010/12/29/health/29radiation.html We are talking 17 years since the 1993 Leveson-Turner article on the Therac. Despite (we will surely hear) `measures' having been `put in place' to prevent such a thing from happening again, it appears to be the same-old same-old. As are the excuses: Medical physicists say there is nothing inherently wrong with linear accelerators that deliver general radiation therapy, as well as SRS. And, they say, the overdoses might have been caught had users followed a more rigorous system of checks and double-checks. ``Tens of thousands of patients have been treated with protocols properly followed and no mistakes were made,'' said Dr. Frank J. Bova, a medical physicist in Gainesville, Fla., and a pioneer in developing and enhancing the accuracy of SRS. ``It has changed many difficult procedures, ones with high surgical risk, into one-day outpatient procedures.'' I wonder. Do we see airline executives on the TV after a major aircraft accident saying "it's only one plane; there are hundreds/thousands of others just like this one flying every day without problems!"? Or Toyota: "it's only one (or a few cars) with bad floormats! There are thousands/millions of cars just like this driving every day without problems!" What is there about medical accidents which lets everyone be comparatively so complacent about them compared with other walks of life such as transportation? Isn't there are Hippocratic oath to the effect of "do no harm"? What is this except doing harm? Is it because the devices are operated by technicians who have not taken the oath, rather than doctors who have? Isn't it about time that professional engineering bodies took a public stand that such events are avoidable and should be avoided? That devices prone to accidents through "operator error" should be taken off the market and redesigned? To adopt the de facto standard set by the aviation industry, that some set party is deemed liable (in aviation: the airline) and pays compensation? (Obvious candidates here would be the manufacturer or the hospital; one would then leave it to the insurance industry to negotiate contributory payments from other parties, as insurance usually does.) There are three general international standards governing the development of safety-related systems involving programmable electronic components (and we may be sure these machines have programmable electronic components). IEC 61508, and its derivatives (so far I know of an international standard for the process industries, a set of European standards for railway systems, and a draft international standard for automobiles), DO178B for aviation, and a separate set of standards, IEC 60601 series, for medical devices. I don't know 60601, but I suspect there is something seriously wrong with the way this whole domain is working if, two decades after Therac, laws still allow safety-critical devices prone to avoidable "operator error" to be used pervasively. Peter Bernard Ladkin, Causalis Limited and University of Bielefeld www.causalis.com www.rvs.uni-bielefeld.de ------------------------------ Date: Wed, 29 Dec 2010 10:14:27 -0500 From: Jeremy Epstein <jeremy.j.epstein_at_private> Subject: How medical radiation mistakes happened Another case where patients were given incorrect (and harmful) doses of radiation, this time because a linear accelerator device had been outfitted with a "cone" to direct radiation, but the design was such that radiation could leak around the edges. *The NY Times* reports that Dr. Howard I. Amols, chief of clinical physics at Memorial Sloan-Kettering Cancer Center in New York, said some problems appeared to be ``a combination of user error, coupled with neither the manufacturers nor the FDA being able to anticipate a potential safety flaw in a `mix and match' treatment delivery system.'' The problem is with a system made by Varian, and involves using three computers: "a treatment plan is developed on one computer, then transferred into another software system that, among other things, verifies that the treatment plan matches the doctor's prescription. The data is then sent to a third computer that controls the linear accelerator." There are also compatibility problems - Varian warned its customers that the "software did not recognize cone attachments on the type of linear accelerator involved in the Evanston accidents.... To work around that problem hospitals needed to, as one medical physicist put it, essentially trick the machine into thinking it was using a different attachment, which it did recognize. To do that, users had to enter additional data into the SRS system. ... Last year, Varian promised to devise, among other things, a decidedly low-tech solution: a decal to stick on the machines, warning operators to be extra careful in setting the radiation field." It appears that part of the problem is that there are two different regulatory regimes - if the machine uses radioactive isotopes it goes through the Nuclear Regulatory Commission, but if it uses a linear accelerator to create the radiation (like the Varian system in this case), the weaker Food and Drug Administration. The RISKS are old - cobbled together systems, or systems with repurposed pieces, are more likely to have mismatches that lead to safety failures, just as we saw with the Therac-25 over 25 years ago. I suspect (although the article does not hint at this) that the continuing pressure to increase usage of expensive machines leaves less time for the medical physicists to learn the machines thoroughly and verify the settings precisely. See also RISKS-24.47, 25.82, 25.92, 25.93, 26.02, and many others.... dating back to 3.09. http://www.nytimes.com/2010/12/29/health/29radiation.html?_r=1&hp ------------------------------ Date: Tue, 21 Dec 2010 09:58:38 -0500 From: John Long <j1long_at_private> Subject: UAVs needed encryption It turns out that communication between ground controllers and UAVs was unencrypted for quite some time. According to the article below, the communication could easily be intercepted using a $26 piece of equipment, which some had been taking advantage. We just began encrypting that communication about a year ago. The risk here is not taking inexpensive precautions against a flaw you are aware of, and assuming your opponent is not sophisticated enough to exploit that flaw. http://www.strategypage.com/htmw/htiw/articles/20101201.aspx ------------------------------ Date: Tue, 21 Dec 2010 18:01:16 -0500 From: Monty Solomon <monty_at_private> Subject: FCC Acts to Preserve Internet Freedom and Openness December 21, 2010 FCC Acts to Preserve Internet Freedom and Openness. Action Helps Ensure Robust Internet for Consumers, Innovation, Investment, Economic Prosperity Washington, D.C. - The Federal Communications Commission today acted to preserve the Internet as an open network enabling consumer choice, freedom of expression, user control, competition and the freedom to innovate. ... http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-303746.pdf Genachowski Statement http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-303746A1.pdf Copps Statement http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-303746A2.pdf McDowell Statement http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-303746A3.pdf Clyburn Statement http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-303746A4.pdf Baker Statement http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-303746A5.pdf [Interesting. The two Democrats are complaining that Genachowski did not go far enough, particularly toward wireless network neutrality, and the two Republicans are complaining that this is too much regulation. And many others are otherwise. PGN] ------------------------------ Date: Mon, 20 Dec 2010 23:21:58 -0500 From: Monty Solomon <monty_at_private> Subject: Technolog - Hackers steal Walgreens e-mail list, attack consumers http://technolog.msnbc.msn.com/_news/2010/12/10/5624759-hackers-steal-walgreens-e-mail-list-attack-consumers ------------------------------ Date: Mon, 20 Dec 2010 21:19:47 -0700 From: Thomas Wicklund <tgwicklund87_at_private> Subject: Risks of incomplete online archives I recently went online looking for an article ("The Religious Success Story" by Jared Diamond, New York Review of Books, Nov 7, 2002). Naturally I first found the New York Review of Books web site (www.nybooks.com). However, I could not find the article. It is not found by a search, not listed in the online contents for that issue, and not listed on the contributor page for Jared Diamond. A web search turned up the article at a different web site on a page with a lot of links to the New York Review of Books web site -- I'm not sure if it's a third party site or an old site of the magazine's. This left me wondering about the veracity of the reference to the article (I've found references to non-existent articles periodically). However, finding an old print copy of a magazine is getting harder and harder. The two closest public libraries didn't keep more than a year or two of this magazine, instead providing a reference to the web site for older issues. I finally found a hard copy of the article at the local university library, though even there it looks like they aren't keeping more than about 10 years of issues in the library. Older issues are available from off-site storage, but again the primary reference is to the magazine's web site. This leaves me wondering about the completeness of electronic archives. We've already lost the exact context of the print magazine (e.g. advertising) when using electronic copies, but with libraries depending more and more on online resources rather than keeping print archives how much information might be lost? Today's online storage has solved the physical problems of aging paper or deteriorating microfilm, but now adds the risk that content can disappear without any indication that it ever existed. [And then there is censorship... Seasons greetings to the censored and the surveilled. PGN] ------------------------------ Date: Tue, 21 Dec 2010 09:55:39 -0500 From: Joe Thompson <joe_at_orion-com.com> Subject: Cell phone "emergency mode" *preventing* 911 call Last night, on my way home from picking up dinner, I passed an accident -- a car overturned in the ditch on the opposite side of the highway. No police or other responders had arrived, so just to be safe I decided to call it in and dialed 911 on my cell phone (an LG enV2). My phone went into "Emergency Mode" with no indication whether the call was connecting or not. At any rate I didn't hear a voice or a ringing phone. I hung up and dialed "911" again, with the same result. At that point out of habit I hit "redial" rather than dialing "911" and heard a phone ringing, but it was my wife who answered -- the phone does not add "911" to its call history, and she was the next-most-recent call. After a brief moment of confusion I figured out what had happened and hung up. I dialed "911" again and this time got through to my county's emergency-services call center, who advised that they were aware of the accident already. I'm perfectly willing to entertain the possibility that I made some sort of simple error the first two times I dialed 911, but it concerns me that my cell phone apparently interfered (or at least made things non-intuitive to the point of interfering) at exactly the time your phone should be most accommodating. The inability to redial 911 from the call history particularly worries me. It's not hard to come up with a scenario in which someone ends up dead because of these kinds of interface misfeatures. Clearly the phone manufacturers (or at least LG) are trying to prevent accidental 911 calls, but I think they may have ended up preventing some real ones as well. -- Joe ------------------------------ Date: Wed, 29 Dec 2010 09:16:04 -0800 From: Lauren Weinstein <lauren_at_private> Subject: China's MIIT Declares Most VOIP Services, Including Skype, Illegal China's MIIT Declares Most VOIP Services, Including Skype, Illegal http://bit.ly/iiqKhV (DigiCha) [As usual, if the tiny url does not work any more, try browsing on the title and don't complain to RISKS. The full info message says NO GUARANTEES ON URLs. Happy New Year. PGN] http://www.vortex.com/lauren +1 (818) 225-2800 PFIR: http://www.pfir.org NNSquad (Network Neutrality Squad): http://www.nnsquad.org Lauren's Blog: http://lauren.vortex.com https://twitter.com/laurenweinstein ------------------------------ Date: Sun, 26 Dec 2010 21:15:54 -0600 From: "Richard S. Russell" <richardsrussell_at_private> Subject: Google Maps vs. USPS in Wisconsin The US Postal Service has a flock of standard abbreviations for street types. For example, it would prefer it if you referred to a county highway as a "COUNTY RD", and "Street" should be abbreviated "ST", while "Avenue" gets reduced to "AVE". (The use of all caps is commensurate with 1970s-level OCR capabilities; I presume the USPS is trying to make its equipment last.) Among the more obscure abbreviations are: * Cove > CV * Dam > DM * Divide > DV Google Maps, in an effort to be helpful, will occasionally expand the USPS abbreviations in its database into the full spelled-out version. Wisconsin, unlike most other states, uses letters to designate county roads. Usually it's only a single letter, but often enuf it's 2, sometimes even 3. You can see where this is headed, can't you? Starting with this view: http://tinyurl.com/24m4y2k which shows County Road DM as "Co. Rd. Dam", you can zoom in a couple of clicks to also discover "Co. Hwy. Cove" (really County Road CV) and "Co. Hwy. Divide" (really County Road DV). Richard S. Russell, 2642 Kendall Av. #2, Madison WI 53705-3736 608+233-5640 RichardSRussell@private http://richardsrussell.livejournal.com/ ------------------------------ Date: Mon, 27 Dec 2010 10:37:46 -0700 From: "Matthew Kruk" <mkrukg_at_private> Subject: Gadgets Bring New Opportunities for Hackers Ashlee Vance, Gadgets Bring New Opportunities for Hackers*, The New York Times*, 26 Dec 2010 http://www.nytimes.com/2010/12/27/technology/27hack.html?_r=1&nl=todaysheadlines&emc=a25 Researchers at Mocana, a security technology company in San Francisco, recently discovered they could hack into a best-selling Internet-ready HDTV model with unsettling ease. They found a hole in the software that helps display Web sites on the TV and leveraged that flaw to control information being sent to the television. They could put up a fake screen for a site like Amazon.com and then request credit card billing details for a purchase. They could also monitor data being sent from the TV to sites. Adrian Turner, Mocana's chief executive: ``Consumer electronics makers as a class seem to be rushing to connect all their products to the Internet. I can tell you for a fact that the design teams at these companies have not put enough thought into security.'' ------------------------------ Date: Tue, 21 Dec 2010 11:20:35 -0800 From: Rob Slade <rMslade_at_private> Subject: Risk Assessment and Failure Analysis ... [This is an OLD item that has never appeared in RISKS before. It's a little late for the holiday season, but still timely. PGN] Risk Assessment and Failure Analysis in Multiple Small Illumination Sources During Winter Conditions Robert M. Slade, version 1.0, 20031217 Q: How many Systems Analysts does it take to change a Christmas light? A: None, Christmas lights are hardware. ABSTRACT In the author's immediate socio-cultural environment, the unpacking, testing, placement, and maintenance of Christmas lights has been mandated to be "man's work." (Women will, reluctantly, direct the placement of lights, since it is an observed fact that a man has all the artistic sensitivity of a Volkswagen. The car, not the automotive designers.) Therefore, despite the complete lack of any evidence of competence in domestic "handiness," or knowledge of electrical appliances, the author has found himself making an extensive, multi- year study of failure modes in different forms of lighting involving multiple small light sources. This paper examines the various failure modes that have been designed as part of different formats of such lighting, and, being a confirmed pessimist, the author conjectures about possible future design failures. INTRODUCTION In the middle of winter, when fogs and rains most abound, the inhabitants of the north western parts of Europe, as well as much of North America, engage in a frenzy of activity. The purpose of many of these exercises is unclear. The sociologist and cultural observer C. S. Lewis (in an essay entitled "Crissmas and Exmas," published in 1947 and for some reason frequently attributed to the much older historian Herodotus) ventures that these endeavours are religious observances in honour of a god that most of the population does not believe exists. On the face of it, this suggestion is absurd. No alternative hypothesis has, though, withstood detailed scrutiny. We examine here the practice of the placement of additional light sources both within and outside domiciles and business establishments during this period. Initial speculation that these sources provided necessary illumination has been demonstrated to be false, despite the shortening and weakening of daylight during this time, since a) the practice is conducted in parts of the world where the additional lighting is not required, b) the levels of illumination produced are insufficient for most work, and c) the light sources appear designed to fail readily, frequently, and in such a manner as to prevent problem rectification. ALTERNATIVE LIGHT SOURCE DESIGNS A variety of technologies has been used in the multiple light source practice. These will be examined in turn. Candles Originally, the light sources used were candles. In particular, candles were placed on or within decorated trees. This gives some weight to the theory of religious observance, since the practitioners would obviously trust in God to allow them to survive the ceremony. The candle technology appears to have fallen out of favour with practitioners, though. There may be many reasons for this, such as the fact that modern cultured and artificial Christmas trees are much denser with foliage than trees used to be, or the fact that by the time all the candles on the tree were lit the first would have burned out. (In a given evening, a typical Christmas tree requires a quantity of candles such that an equivalent amount of gasoline would drive a Volkswagen approximately fifty kilometres.) Candlelit Christmas trees are subject to catastrophic failure modes. On the positive side, there is no need to perform any maintenance or testing once a failure has occurred. Incandescent Bulbs The designation and definition of incandescent bulbs, in regard to Christmas lights, is problematic, given that at least two other forms of illumination also use incandescent filaments, and because the word "incandescent" is inconvenient both to write and to spell. For the purposes of this paper, incandescents will be defined as being subject to 120 volt electrical power requirements, and greater than 1 cm in diameter in physical size. Sociologically, the devotees of incandescents are considered to use "traditional" Christmas lights. There are, in fact, two physical sizes of incandescents. The larger are approximately 4 cm in length and about 2 cm in diameter. These are generally 7 watt bulbs, and are referred to as "outside" lights, although they may also be used on large displays in commercial establishments indoors, particularly where the brightness of the smaller incandescents would not be particularly noticeable. (See the earlier note regarding the utility of Christmas light illumination.) The smaller lights, usually known as "indoor" bulbs, are roughly 2.5 cm in length and a little over a centimetre in diameter. In both cases the bulbs are something of a pear or teardrop shape. (There are a number of variations on these basic models. Reflective or refractive covers may be put around or behind the bulbs, and the bulb sockets may support electrical appliances which run motors creating mobile displays such as spinning carousels or teddy bears. These additions do not affect the basic failure analysis model, and so will not be considered here. A notable exception are "bubble lights," which use the heat of the bulb to create a continual cycle of evaporation and condensation in a tube of a water/alcohol mixture. Bubble lights are quite rare, and are usually stated to be an "ironic statement in regard to kitsch" by those who are afraid to admit that they really like them. However, we were unable to obtain sufficient data on failure rates, particularly in regard to explosive failure, to add them to the models under consideration.) Christmas lights are arranged in sets of "strings," with bases attached at intervals along a set of power cables. Incandescent bulbs are wired in parallel, such that the failure of one bulb will not cause the entire string to fail. However, the current draw along the power cables, particularly given the practice of joining strings together in one long string, requires that the cabling be of significant density. (Outdoor bulbs are generally seven watts, and are arranged in strings of twenty five bulbs. Therefore, a single cable will be carrying 175 watts, or about 1.5 amps of current. Outlining the eaves of a typical domicile will often require five strings, placing a load of 7.5 amps at the base of the long string. In situations where residents illuminate trees and bushes in the yard as well, the current load can exceed this by a substantial margin.) Therefore, incandescent strings are based on heavy gauge wire, with correspondingly heavy insulation. (It should be noted that, despite the identical power requirements, "indoor" and "outdoor" incandescent bulbs have proportionately sized bases, ensuring that neither can be used in the strings of the other, and requiring that replacements be available for both sizes.) Incandescent strings are therefore not subject to simple failures that would occur in lighter equipment. They are, though, very difficult to manipulate, store, and retrieve from storage. This ensures that bulbs fail frequently due to mishandling during the manipulation process known as "putting the lights up" or the corresponding "putting the lights away." Some light practitioners have therefore undertaken to putting lights (particularly outside lights) in place, and then leaving them there. However, Christmas lights are, as noted, not designed purely for illumination: they are coloured, so that the ultimate effect of Christmas lights is similar to that of seeing a multitude of different coloured Volkswagens in a parking lot. The bulbs have been designed in two ways. The first applies colour as coloured paint, ensuring that any bulbs left outside for long periods of time become scratched by branches and thus become colourless. The later design is to apply the colour with a film of plastic: this design ensures that the film degrades with the "hot/cold" cycle that is engendered by bulbs that are turned on for brief periods during cold weather. The film eventually flakes off, again leaving the bulbs with limited colour. Minilights Minilights use incandescent filaments, but are much smaller than the more traditional incandescent bulbs. Minilight bulbs are roughly .5cm in diameter and 2 cm in length. The bulbs sport two bare wires, and must be mounted in a separate base before being placed in a string. There is no difference whatsoever in size, form, or markings regardless of whether minilight bulbs are 2 volt, 2.5 volt, 3, 3.5, 4, 5, 6, 7, 8, 10, or 12 volt, nor whether they are ordinary bulbs or "flashers." (Flashing bulbs are known to trigger seizures in those subject to epilepsy, and extreme agitation and annoyance in most of the rest of the population, similar to the Netscape <blink> blink </blink> tag, or following a Volkswagen for thirty two miles down the freeway with the left turn flasher stuck on.) There is also no particular indication that a bulb is dead, other than the fact that it does not work. (Traditional incandescent bulbs are generally large enough that the filament is visible to the naked eye, except, of course, if the bulb is of the painted variety.) Despite the universal nature of the bulb sizes, the bases for minilights vary from string to string, and many strings will, in fact, have multiple incompatible sizes of bases that must be used in the correct sockets along that string. Minilight bulbs are strung in series. A rough estimate of the voltage requirement for a string may be obtained from the number of sockets, but this is not a completely reliable indication. (Many strings are, in fact, multiple strings, wired in parallel with each other. Therefore, a failure may leave half the string usable, but use of such a string is seen as an admission of failure of manhood (see above in regard to gender roles in respect of Christmas lights). Minilight bulbs, being strung in series, would be subject to complete failure of a string if a single bulb were to burn out. The bulbs are, therefore, designed such that the burning out of a bulb also creates a "burn-through" in order to maintain the electrical circuit. As with all religious practices there is an attendant element of randomness: sometimes the burn-through works, and sometimes it doesn't. Because of the universal size, bulbs of differing voltage may be used in a single string, or bulbs of an inappropriate voltage may be used in a string. When, for example, twelve volt bulbs are used in a string wired for seven volt bulbs, the bulbs will work, although they will burn very dimly. Seven volt bulbs may also be used in a string wired for twelve volt bulbs. This practice is much more interesting. Due to the higher temperature and stress, eventually a bulb will burn out. However, due to the burn-through design, this will still leave the rest of the string burning and will, in fact, increase the brilliance of the illumination. This also increases the thermal stress, though, and therefore an additional bulb will blow out in a lesser period of time. After the failure of one or two more bulbs, the whole string goes in rapid succession: in the words of one observer, "like a string of firecrackers." Because of the universal bulb size, the lack of differentiation between live and dead bulbs, and the bulb burn-through design, failure analysis of a string is problematic. There is the practice of individually removing each bulb and socket, removing the bulb from the socket, and replacing it with a bulb known to be good. This procedure has been cited in the psychological literature due to its relation to serious nervous conditions that result when the practitioner realizes that he has been testing with a bulb that is actually dead, or fruitlessly comes to the end of a test of several strings and realizes that it was more than possible that multiple bulbs on the string were dead. (This assessment is also complicated by the randomness of the burn-through factor noted above.) Experienced practitioners (if they escape the nervous conditions noted above) find that bulbs and sockets must be individually removed, the bulb removed from the socket, and tested by placing it into a socket of a string that is known to be good. Frequently as many as a quarter of the bulbs on a string must be replaced before the string becomes usable again, and even then a number of bulbs can be identified as needing to be replaced for full illumination. (As noted, complete illumination has no functional purpose, but is practiced by the masters of the craft as a prophylactic against string failure during the Christmas season.) Light Ropes Light ropes combine the failure characteristics of minilights with the difficulty of manipulation of traditional incandescents, and add the ease of maintenance of spy satellites (as opposed to, say, original model Volkswagens). Also, many religious leaders hold them to be an abomination and offence against nature. LEDs The latest technology in Christmas lights involves Light Emitting Diodes, or LEDs. LEDs provide a much greater efficiency of conversion of electricity to light than do other forms of lighting technology. In addition, the manufacturers of LED Christmas light have chosen to go the conservation route. Door and Window outlining of a typical domicile can be achieved for the entire Christmas season (with the lights left on 24 hours per day) for roughly the cost of a local call on a pay phone (if you can find one, in these days of ubiquitous cellular phones). Unfortunately, the level of illumination provided is quite low: the entire light output of several strings is scarcely enough to allow you to find your way around the inside of a Volkswagen. LEDs are wired in series, like minilights, and are designed with the same burn-through technology. As well as being more efficient, LEDs are also said to be more durable, although this, being a new technology, has not been put to practical tests. Therefore, it is felt that LED Christmas light strings will be longer lasting, and the manufacturers boast of a five-year guarantee. This promise is marred by only two considerations. The first is the low probability that the manufacturers are in any danger of having to provide replacements for such a low cost item. The second is the fact that the light strings are also said to be resistant to a failure of a single bulb, but have absolutely no provision for replacement: all bulbs are hardwired into the string. If a second bulb goes, you are supposed to throw the string away. CONCLUSION Given the failure characteristics of Christmas lights, the hypothesis of religious observance (similar to penitential exercises seen in other cases) must be supported, even in the complete absence of evidence of a belief system. The author wishes the readers a very Merry Christmas and a Happy New Year. (Failing that, the author wishes the readers a very happy Generic Mid-Winter Party Period.) ACKNOWLEDGMENTS This work has been supported by research performed by Erichson Engineering, the Vancouver Centre of Excellence of Honeywell Process Solutions, and Gloria J. Slade. rslade_at_private slade_at_private rslade_at_private victoria.tc.ca/techrev/rms.htm blog.isc2.org/isc2_blog/slade/index.html http://blogs.securiteam.com/index.php/archives/author/p1/ http://www.infosecbc.org/links http://twitter.com/rslade ------------------------------ Date: Thu, 29 May 2008 07:53:46 -0900 From: RISKS-request_at_private Subject: Abridged info on RISKS (comp.risks) The ACM RISKS Forum is a MODERATED digest, with Usenet equivalent comp.risks. => SUBSCRIPTIONS: PLEASE read RISKS as a newsgroup (comp.risks or equivalent) if possible and convenient for you. 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