Older blog entries for etbe (starting at number 1138)

Android Screen Saving

Just over a year ago I bought a Samsung Galaxy Note 2 [1]. About 3 months ago I noticed that some of the Ingress menus had burned in to the screen. Back in ancient computer times there were “screen saver” programs that blanked the screen to avoid this, then the “screen saver” programs transitioned to displaying a variety of fancy graphics which didn’t really fulfill the purpose of saving the screen. With LCD screens I have the impression that screen burn wasn’t an issue, but now with modern phones we have LED displays which have the problem again.

Unfortunately there doesn’t seem to be a free screen-saver program for Android in the Google Play store. While I can turn the screen off entirely there are some apps such as Ingress that I’d like to keep running while the screen is off or greatly dimmed. Now I sometimes pull the notification menu down when I’m going to leave Ingress idle for a while, this doesn’t stop the screen burning but it does cause different parts to burn which alleviates the problem.

It would be nice if apps were designed to alleviate this. A long running app should have an option to change the color of it’s menus, it would be ideal to randomly change the color on startup. If the common menus such as the “COMM” menu would appear in either red, green, or blue (the 3 primary colors of light) in a ratio according to the tendency to burn (blue burns fastest so should display least) then it probably wouldn’t cause noticable screen burn after 9 months. The next thing that they could do is to slightly vary the position of the menus, instead of having a thin line that’s strongly burned into the screen there would be a fat line lightly burned in which should be easier to ignore.

It’s good when apps have an option of a “dark” theme, that involves less light coming from the screen that should reduce battery use and screen burn. A dark theme should be at least default and probably mandatory for long running apps, a dark theme is fortunately the only option for Ingress.

I am a little disappointed with my phone. I’m not the most intensive Ingress player so I think that the screen should have lasted for more than 9 months before being obviously burned.

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Syndicated 2014-07-29 12:28:51 from etbe - Russell Coker

Happiness and Lecture Questions

I just attended a lecture about happiness comparing Australia and India at the Australia India Institute [1]. The lecture was interesting but the “questions” were so bad that it makes a good case for entirely banning questions from public lectures. Based on this and other lectures I’ve attended I’ve written a document about how to recognise worthless questions and cut them off early [2].

As you might expect from a lecture on happiness there were plenty of stupid comments from the audience about depression, as if happiness is merely the absence of depression.

Then they got onto stupidity about suicide. One “question” claimed that Australia has a high suicide rate, Wikipedia however places Australia 49th out of 110 countries, that means Australia is slightly above the median for suicide rates per country. Given some of the dubious statistics in the list (for example the countries claiming to have no suicides and the low numbers reported by some countries with extreme religious policies) I don’t think we can be sure that Australia would be above the median if we had better statistics. Another “question” claimed that Sweden had the highest suicide rate in Europe, while Greenland, Belgium, Finland, Austria, France, Norway, Denmark, Iceland, and most of Eastern Europe are higher on the list.

But the bigger problem in regard to discussing suicide is that the suicide rate isn’t about happiness. When someone kills themself because they have a terminal illness that doesn’t mean that they were unhappy for the majority of their life and doesn’t mean that they were any unhappier than the terminally ill people who don’t do that. Some countries have a culture that is more positive towards suicide which would increase the incidence, Japan for example. While people who kill themselves in Japan are probably quite unhappy at the time I don’t think that there is any reason to believe that they are more unhappy than people in other countries who only keep living because suicide is considered to be wrong.

It seems to me that the best strategy when giving or MCing a lecture about a potentially contentious topic is to plan ahead for what not to discuss. For a lecture about happiness it would make sense to rule out all discussion of suicide, anti-depressants, and related issues as they aren’t relevant to the discussion and can’t be handled in an appropriate manner in question time.

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Syndicated 2014-07-29 10:57:37 from etbe - Russell Coker

Public Lectures About FOSS

Eventbrite

I’ve recently started using the Eventbrite Web site [1] and the associated Eventbrite Android app [2] to discover public events in my area. Both the web site and the Android app lack features for searching (I’d like to save alerts for my accounts and have my phone notify me when new events are added to their database) but it is basically functional. The main issue is content, Eventbrite has a lot of good events in their database (I’ve got tickets for 6 free events in the next month). I assume that Eventbrite also has many people attending their events, otherwise the events wouldn’t be promoted there.

At this time I haven’t compared Eventbrite to any similar services, Eventbrite events have taken up much of my available time for the next 6 weeks (I appreciate the button on the app to add an entry to my calendar) so I don’t have much incentive to find other web sites that list events. I would appreciate comments from users of competing event registration systems and may write a post in future comparing different systems. Also I have only checked for events in Melbourne, Australia as I don’t have any personal interest in events in other places. For the topic of this post Eventbrite is good enough, it meets all requirements for Melbourne and I’m sure that if it isn’t useful in other cities then there are competing services.

I think that we need to have free FOSS events announced through Eventbrite. We regularly have experts in various fields related to FOSS visiting Melbourne who give a talk for the Linux Users of Victoria (and sometimes other technical groups). This is a good thing but I think we could do better. Most people in Melbourne probably won’t attend a LUG meeting and if they did they probably wouldn’t find it a welcoming experience.

Also I recommend that anyone who is looking for educational things to do in Melbourne visit the Eventbrite web site and/or install the Android app.

Accessible Events

I recently attended an Eventbrite event where a professor described the work of his research team, it was a really good talk that made the topic of his research accessible to random members of the public like me. Then when it came to question time the questions were mostly opinion pieces disguised as questions which used a lot of industry specific jargon and probably lost the interest of most people in the audience who wasn’t from the university department that hosted the lecture. I spent the last 15 minutes in that lecture hall reading Wikipedia and resisted the temptation to load an Android game.

Based on this lecture (and many other lectures I’ve seen) I get the impression that when the speaker or the MC addresses a member of the audience by name (EG “John Smith has a question”) then it’s strongly correlated with a low quality question. See my previous post about the Length of Conference Questions for more on this topic [3].

It seems to me that when running a lecture everyone involved has to agree about whether it’s a public lecture (IE one that is for any random people) as opposed to a society meeting (which while free for anyone to attend in the case of a LUG is for people with specific background knowledge). For a society meeting (for want of a better term) it’s OK to assume a minimum level of knowledge that rules out some people. If 5% of the audience of a LUG don’t understand a lecture that doesn’t necessarily mean it’s a bad lecture, sometimes it’s not possible to give a lecture that is easily understood by those with the least knowledge that also teaches the most experienced members of the audience.

For a public lecture the speaker has to give a talk for people with little background knowledge. Then the speaker and/or the MC have to discourage or reject questions that are for a higher level of knowledge.

As an example of how this might work consider the case of an introductory lecture about how an OS kernel works. When one of the experienced Linux kernel programmers visits Melbourne we could have an Eventbrite event organised for a lecture introducing the basic concepts of an OS kernel (with Linux as an example). At such a lecture any questions about more technical topics (such as specific issues related to compilers, drivers, etc) could be met with “we are having a meeting for more technical people at the Linux Users of Victoria meeting tomorrow night” or “we are having coffee at a nearby cafe afterwards and you can ask technical questions there”.

Planning Eventbrite Events

When experts in various areas of FOSS visit Melbourne they often offer a talk for LUV. For any such experts who read this post please note that most lectures at LUV meetings are by locals who can reschedule, so if you are only in town for a short time we can give you an opportunity to speak at short notice.

I would like to arrange to have some of those people give a talk aimed at a less experienced audience which we can promote through Eventbrite. The venue for LUV talks (Melbourne University 7PM on the first Tuesday of the month) might not work for all speakers so we need to find a sponsor for another venue.

I will contact Linux companies that are active in Melbourne and ask whether they would be prepared to sponsor the venue for such a talk. The fallback option would be to have such a lecture at a LUV meeting.

I will talk to some of the organisers of science and technology events advertised on Eventbrite and ask why they chose the times that they did. Maybe they have some insight into which times are best for getting an audience. Also I will probably get some idea of the best times by just attending many events and observing the attendance. I think that the aim of an Eventbrite event is to attract delegates who wouldn’t attend other meetings, so it is a priority to choose a suitable time and place.

Finally please note that while I am a member of the LUV committee I’m not representing LUV in this post. My aim is that community feedback on this post will help me plan such events. I will discuss this with the LUV committee after I get some comments here.

Please comment if you would like to give such a public lecture, attend such a lecture, or if you just have any general ideas.

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Syndicated 2014-07-22 08:22:17 from etbe - Russell Coker

Improving Computer Reliability

In a comment on my post about Taxing Inferior Products [1] Ben pointed out that most crashes are due to software bugs. Both Ben and I work on the Debian project and have had significant experience of software causing system crashes for Debian users.

But I still think that the widespread adoption of ECC RAM is a good first step towards improving the reliability of the computing infrastructure.

Currently when software developers receive bug reports they always wonder whether the bug was caused by defective hardware. So when bugs can’t be reproduced (or can’t be reproduced in a way that matches the bug report) they often get put in a list of random crash reports and no further attention is paid to them.

When a system has ECC RAM and a filesystem that uses checksums for all data and metadata we can have greater confidence that random bugs aren’t due to hardware problems. For example if a user reports a file corruption bug they can’t repeat that occurred when using the Ext3 filesystem on a typical desktop PC I’ll wonder about the reliability of storage and RAM in their system. If however the same bug report came from someone who had ECC RAM and used the ZFS filesystem then I would be more likely to consider it a software bug.

The current situation is that every part of a typical PC is unreliable. When a bug can be attributed to one of several pieces of hardware, the OS kernel and even malware (in the case of MS Windows) it’s hard to know where to start in tracking down a bug. Most users have given up and accepted that crashing periodically is just what computers do. Even experienced Linux users sometimes give up on trying to track down bugs properly because it’s sometimes very difficult to file a good bug report. For the typical computer user (who doesn’t have the power that a skilled Linux user has) it’s much worse, filing a bug report seems about as useful as praying.

One of the features of ECC RAM is that the motherboard can inform the user (either at boot time, after a NMI reboot, or through system diagnostics) of the problem so it can be fixed. A feature of filesystems such as ZFS and BTRFS is that they can inform the user of drive corruption problems, sometimes before any data is lost.

My recommendation of BTRFS in regard to system integrity does have a significant caveat, currently the system reliability decrease due to crashes outweighs the reliability increase due to checksums at this time. This isn’t all bad because at least when BTRFS crashes you know what the problem is, and BTRFS is rapidly improving in this regard. When I discuss BTRFS in posts like this one I’m considering the theoretical issues related to the design not the practical issues of software bugs. That said I’ve twice had a BTRFS filesystem seriously corrupted by a faulty DIMM on a system without ECC RAM.

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Syndicated 2014-07-11 04:51:55 from etbe - Russell Coker

A Linux Conference as a Ritual

Sociological Images has an interesting post by Jay Livingston PhD about a tennis final as a ritual [1]. The main point is that you can get a much better view of the match on your TV at home with more comfort and less inconvenience, so what you get for the price of the ticket (and all the effort of getting there) is participating in the event as a spectator.

It seems to me that the same idea applies to community Linux conferences (such as LCA) and some Linux users group meetings. In terms of watching a lecture there are real benefits to downloading it after the conference so that you can pause it and study related web sites or repeat sections that you didn’t understand. Also wherever you might sit at home to watch a video of a conference lecture you will be a lot more comfortable than a university lecture hall. Some people don’t attend conferences and users’ group meetings because they would rather watch a video at home.

Benefits of Attending (Apart from a Ritual)

One of the benefits of attending a lecture is the ability to ask questions. But that seems to mostly apply to the high status people who ask most questions. I’ve previously written about speaking stacks and my observations about who asks questions vs the number that can reasonably be asked [2].

I expect that most delegates ask no questions for the entire conference. I created a SurveyMonkey survey to discover how many questions people ask [3]. I count LCA as a 3 day conference because I am only counting the days where there are presentations that have been directly approved by the papers committee, approving a mini-conf (and thus delegating the ability to approve speeches) is different.

Another benefit of attending is the so-called “hallway track” where people talk to random other people. But that seems to be of most benefit to people who have some combination of high status in the community and good social skills. In the past I’ve attended the “Professional Delegates Networking Session” which is an event for speakers and people who pay the “Professional” registration fee. Sometimes at such events there has seemed to be a great divide between speakers (who mostly knew each other before the conference) and “Professional Delegates” which diminishes the value of the event to anyone who couldn’t achieve similar benefits without it.

How to Optimise a Conference as a Ritual

To get involvement of people who have the ritualistic approach one could emphasise the issue of being part of the event. For example to get people to attend the morning keynote speeches (which are sometimes poorly attended due to partying the night before) one could emphasise that anyone who doesn’t attend the keynote isn’t really attending the conference.

Conference shirts seem to be strongly correlated with the ritual aspect of conferences, the more “corporate” conferences don’t seem to offer branded clothing to delegates. If an item of branded schwag was given out before each keynote then that would increase the attendance by everyone who follows the ritual aspect (as well as everyone who just likes free stuff).

Note that I’m not suggesting that organisers of LCA or other conferences go to the effort of giving everyone schwag before the morning keynote, that would be a lot of work. Just telling people that anyone who misses the keynote isn’t really attending the conference would probably do.

I’ve always wondered why conference organisers want people to attend the keynotes and award prizes to random delegates who attend them. Is a keynote lecture a ritual that is incomplete if the attendance isn’t good enough?

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Syndicated 2014-07-10 08:00:28 from etbe - Russell Coker

Taxing Inferior Products

I recently had a medical appointment cancelled due to a “computer crash”. Apparently the reception computer crashed and lost all bookings for a day and they just made new bookings for whoever called – and anyone who had a previous booking just missed out. I’ll probably never know whether they really had a computer problem or just used computer problems as an excuse when they made a mistake. But even if it wasn’t a real computer problem the fact that computers are so unreliable overall that “computer crash” is an acceptable excuse indicates a problem with the industry.

The problem of unreliable computers is a cost to everyone, it’s effectively a tax on all business and social interactions that involve computers. While I spent the extra money on a server with ECC RAM for my home file storage I have no control over the computers purchased by all the companies I deal with – which are mostly the cheapest available computers. I also have no option to buy a laptop with ECC RAM because companies like Lenovo have decided not to manufacture them.

It seems to me that the easiest way of increasing overall reliability of computers would be to use ECC RAM everywhere. In the early 90′s all IBM compatible PCs had parity RAM, that meant that for each byte there was one extra bit which would report 100% of single-bit errors and 50% of errors that involved random memory corruption. Then manufacturers decided to save a tiny amount of money on memory by using 8/9 the number of chips for desktop/laptop systems and probably make more money on selling servers with ECC RAM. If the government was to impose a 20% tax on computers that lack ECC RAM then manufacturers would immediately start using it everywhere and the end result would be no price increase overall as it’s cheaper to design desktop systems and servers with the same motherboards – apparently some desktop systems have motherboard support for ECC RAM but don’t ship with suitable RAM or advertise the support for such RAM.

This principle applies to many other products too. One obvious example is cars, a car manufacturer can sell cheap cars with few safety features and then when occupants of those cars and other road users are injured the government ends up paying for medical expenses and disability pensions. If there was a tax for every car that has a poor crash test rating and a tax for every car company that performs badly in real world use then it would give car companies some incentive to manufacture safer vehicles.

Now there are situations where design considerations preclude such features. For example implementing ECC RAM in mobile phones might involve technical difficulties (particularly for 32bit phones) and making some trucks and farm equipment safer might be difficult. But when a company produces multiple similar products that differ significantly in quality such as PCs with and without ECC RAM or cars with and without air-bags there would be no difficulty in making them all of them higher quality.

I don’t think that we will have a government that implements such ideas any time soon, it seems that our government is more interested in giving money to corporations than taxing them. But one thing that could be done is to adopt a policy of only giving money to companies if they produce high quality products. If a car company is to be given hundreds of millions of dollars for not closing a factory then that factory should produce cars with all possible safety features. If a computer company is going to be given significant tax breaks for doing R&D then they should be developing products that won’t crash.

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Syndicated 2014-07-10 02:48:38 from etbe - Russell Coker

Desktop Publishing is Wrong

When I first started using computers a “word processor” was a program that edited text. The most common and affordable printers were dot-matrix and people who wanted good quality printing used daisy wheel printers. Text from a word processor was sent to a printer a letter at a time. The options for fancy printing were bold and italic (for dot-matrix), underlines, and the use of spaces to justify text.

It really wasn’t much good if you wanted to include pictures, graphs, or tables. But if you just wanted to write some text it worked really well.

When you were editing text it was typical that the entire screen (25 rows of 80 columns) would be filled with the text you were writing. Some word processors used 2 or 3 lines at the top or bottom of the screen to display status information.

Some time after that desktop publishing (DTP) programs became available. Initially most people had no interest in them because of the lack of suitable printers, the early LASER printers were very expensive and the graphics mode of dot matrix printers was slow to print and gave fairly low quality. Printing graphics on a cheap dot matrix printer using the thin continuous paper usually resulted in damaging the paper – a bad result that wasn’t worth the effort.

When LASER and Inkjet printers started to become common word processing programs started getting many more features and basically took over from desktop publishing programs. This made them slower and more cumbersome to use. For example Star Office/OpenOffice/LibreOffice has distinguished itself by remaining equally slow as it transitioned from running on an OS/2 system with 16M of RAM in the early 90′s to a Linux system with 256M of RAM in the late 90′s to a Linux system with 1G of RAM in more recent times. It’s nice that with the development of PCs that have AMD64 CPUs and 4G+ of RAM we have finally managed to increase PC power faster than LibreOffice can consume it. But it would be nicer if they could optimise for the common cases. LibreOffice isn’t the only culprit, it seems that every word processor that has been in continual development for that period of time has had the same feature bloat.

The DTP features that made word processing programs so much slower also required more menus to control them. So instead of just having text on the screen with maybe a couple of lines for status we have a menu bar at the top followed by a couple of lines of “toolbars”, then a line showing how much width of the screen is used for margins. At the bottom of the screen there’s a search bar and a status bar.

Screen Layout

By definition the operation of a DTP program will be based around the size of the paper to be used. The default for this is A4 (or “Letter” in the US) in a “portrait” layout (higher than it is wide). The cheapest (and therefore most common) monitors in use are designed for displaying wide-screen 16:9 ratio movies. So we have images of A4 paper with a width:height ratio of 0.707:1 displayed on a wide-screen monitor with a 1.777:1 ratio. This means that only about 40% of the screen space would be used if you don’t zoom in (but if you zoom in then you can’t see many rows of text on the screen). One of the stupid ways this is used is by companies that send around word processing documents when plain text files would do, so everyone who reads the document uses a small portion of the screen space and a large portion of the email bandwidth.

Note that this problem of wasted screen space isn’t specific to DTP programs. When I use the Google Keep website [1] to edit notes on my PC they take up a small fraction of the screen space (about 1/3 screen width and 80% screen height) for no good reason. Keep displays about 70 characters per line and 36 lines per page. Really every program that allows editing moderate amounts of text should allow more than 80 characters per line if the screen is large enough and as many lines as fit on the screen.

One way to alleviate the screen waste on DTP programs is to use a “landscape” layout for the paper. This is something that all modern printers support (AFAIK the only printers you can buy nowadays are LASER and ink-jet and it’s just a big image that gets sent to the printer). I tried to do this with LibreOffice but couldn’t figure out how. I’m sure that someone will comment and tell me I’m stupid for missing it, but I think that when someone with my experience of computers can’t easily figure out how to perform what should be a simple task then it’s unreasonably difficult for the vast majority of computer users who just want to print a document.

When trying to work out how to use landscape layout in LibreOffice I discovered the “Web Layout” option in the “View” menu which allows all the screen space to be used for text (apart from the menu bar, tool bars, etc). That also means that there are no page breaks! That means I can use LibreOffice to just write text, take advantage of the spelling and grammar correcting features, and only have screen space wasted by the tool bars and menus etc.

I never worked out how to get Google Docs to use a landscape document or a single webpage view. That’s especially disappointing given that the proportion of documents that are printed from Google Docs is probably much lower than most word processing or DTP programs.

What I Want

What I’d like to have is a word processing program that’s suitable for writing draft blog posts and magazine articles. For blog posts most of the formatting is done by the blog software and for magazine articles the editorial policy demands plain text in most situations, so there’s no possible benefit of DTP features.

The ability to edit a document on an Android phone and on a Linux PC is a good feature. While the size of a phone screen limits what can be done it does allow jotting down ideas and correcting mistakes. I previously wrote about using Google Keep on a phone for lecture notes [2]. It seems that the practical ability of Keep to edit notes on a PC is about limited to the notes for a 45 minute lecture. So while Keep works well for that task it won’t do well for anything bigger unless Google make some changes.

Google Docs is quite good for editing medium size documents on a phone if you use the Android app. Given the limitations of the device size and input capabilities it works really well. But it’s not much good for use on a PC.

I’ve seen a positive review of One Note from Microsoft [3]. But apart from the fact that it’s from Microsoft (with all the issues that involves) there’s the issue of requiring another account. Using an Android phone requires a Gmail account (in practice for almost all possible uses if not in theory) so there’s no need to get an extra account for Google Keep or Docs.

What would be ideal is an Android editor that could talk to a cloud service that I run (maybe using WebDAV) and which could use the same data as a Linux-X11 application.

Any suggestions?

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Syndicated 2014-07-06 06:53:58 from etbe - Russell Coker

Blog Comments

John Scalzi wrote an insightful post about the utility of blog comments with the way the Internet works nowadays [1]. He starts out focusing on hate comments that could reasonably be described as terrorism (death threats with the aim of preventing people writing about politics meet any reasonable definition of “terrorism”). Terrorists on the Internet are a significant problem but it’s one that doesn’t get much attention as it generally only affects people who aren’t straight-acting white men.

Blogging About Technology

One corner case that John doesn’t seem to consider is that of writing about technology. Issues related to programming often aren’t related to politics and are often testable so comments will be based on things that have been shown to work rather than stuff people invent or want to believe. I’ve received many useful and educational comments on my technical posts with little hostility. Even getting a snarky comment is rare when writing a strictly technical blog post.

The comments problem for technology blogging is spam. I’ve been using the WordPress plugin Block Spam by Math [2] (which is obsolete but still works) for years. Initially it stopped almost all spam, but now I’m getting at least 20 spam comments a day.

Extremely Popular Blogs

The comments section of a blog is sometimes described as a “conversation”. When a blog post gets comments from less than 10 people it is possible for them to have something that resembles a conversation with the author that is of benefit to other readers and doesn’t take excessive amounts of time for the author. When a blog is very popular and every post gets comments from 50+ people it’s not really possible. So a traditional blog comment section seems to work best when the blog is primarily read by a small well connected group of people who sometimes comment and some casual readers who never comment (but sometimes find value in the comments of others).

Discussions of blog comment systems usually include a reference to a post written by someone who disabled comments on their blog and found it to be a good thing, it always seems that the person who writes such a post has a large and varied audience who’s comments would take a lot of time to moderate. John followed the usual form in this regard by linking to a reasonably popular SF author who would presumably have a lot of fans with good net access.

I’m not going to criticise anyone for disabling comments when their blog becomes really popular, but any advice that they have to offer about such things won’t apply to the vast majority of blogs. Due to the long-tail effect the small blogs would probably comprise the majority of all comments so in terms of the way the blog environment works I don’t think it makes much difference when the small minority of very popular blogs disable comments. The vast majority of blogs that I regularly read only have a small number of comments.

One thing that should be noted is that getting a lot of readers shouldn’t be the only factor for writing a successful blog. For example some of my blog posts about SE Linux are aimed at a small audience of Linux programmers and have an even smaller number of people who are qualified to comment. When I write a post that can only receive comments other than “please explain more because I don’t understand” from a few dozen people that doesn’t make it any less important. Sometimes the few dozen people who know a topic well need to work together to educate the few thousand who can implement the ideas for the benefit of millions of users of the software.

Disabling Comments on Contentious Posts

One interesting method John uses is to disable comments early when posting about contentious issues. It’s a general practice when running a blog to disable comments on posts after a certain period of time (3 months to 1 year seem to be common time limits for comments). This means that the moderators can concentrate on recent posts and not be bothered with spam bots hitting ancient posts as the interest in writing legitimate comments on an old post is vanishingly small. John has a practice of disabling comments after a couple of days when the comments start to lose quality.

No matter how contentious the issue is I’m not likely to get the 400+ comments that John gets. But the idea of closing comments quickly still has some merit for my blog and other blogs with less traffic.

Not Accepting Comments While Asleep

John has a practice of closing comments while he’s asleep to avoid allowing a troll to get 8 hours of viewing for a nasty comment. The most immediate down-side to that is that it inconveniences people who don’t want to wait 8 hours to comment and prioritises comments from people in the same time zone, this makes me think of Cory Doctorow’s novel Eastern Standard Tribe (which is available for free download and I highly recommend reading it) [3]. It seems that a better solution to that problem would be to have a team of moderators to watch things 24*7 which is what a lot of popular blogs that allow comments do. The WordPress capabilities model doesn’t support granting a user no special privileges other than moderating comments [4], as WordPress is the most popular self-hosted blog software this limits the possibilities for people moderating comments on other people’s blogs.

No variation of this would work for me. I have lots of things that require my ongoing attention and don’t want to add my blog to the list. If I have other things to work on for a few days I want to just not bother with my blog. This means that my blog needs to be able to run on autopilot for days at a time – however I do monitor my blog closely after publishing a post that is likely to attract nasty comments. One extra problem that I have is that the Android client for WordPress has problems in synchronising comments.

Using a Forum for Comments

Popular Planet installations such as Planet Debian and Planet Linux Australia syndicate more than a few blogs that have comments disabled. A forum installation for such a Planet would be useful to allow people to comment on all posts and also support bloggers who are thinking of disabling comments. While the use of a forum for blog comments has been proven to work well for Boing Boing forums have their own issues of spam and anti-social behavior.

Debian already has a forum [5], if a section of that was devoted to discussing blog posts from Planet Debian then it shouldn’t make much of an increase to the work of the forum administrators while providing a benefit to the community. Also if the Debian forum had such a section it would probably attract use from more Debian Developers, I would use that forum if it was a place to comment on blogs that don’t have a comment section and I might also comment on other forum discussions.

It would be good if there was a forum for discussing Linux in Australia. I’m not volunteering to run it but I would help out if someone else wants to be the main sysadmin and I can offer free hosting.

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Syndicated 2014-07-01 03:34:36 from etbe - Russell Coker

Links June 2014

Russ Albery wrote an insightful blog post about trust, computer security, and training programmers [1]. He makes a good case that social problems in our community decrease the availability of skilled people to write and audit security code.

The Lawfare blog has an insightful article by Dan Geer about “Heartbleed as a Metaphor [2]. He makes some good points about security and design, ways of potentially solving some flaws and problems with the various solutions.

Eben Moglen wrote an insightful article for The Guardian about the way that the NSA spying is a direct threat to democracy [3]

The TED blog has an interesting interview with Kitra Cahana about her work living with and photographing nomads in the US [4]. I was surprised to learn that there’s an active nomad community in the US based on the culture that started in the Great Depression. Apparently people are using Youtube to learn about nomad culture before joining.

Dave Johnson wrote an interesting Salon article about why CEOs make 300* as much money as workers [5]. Note that actually contributing to the financial success of the company is not one of the reasons.

Maia Szalavitz wrote an interesting Slate article about Autism and Anorexia [6]. Apparently some people on the Autism Spectrum are mis-diagnosed with Anorexia due to food intolerance.

Groups of four professors have applied for the job of president and vice-chancellor of the University of Alberta [7]. While it was a joke to apply in that way, 1/4 of the university president’s salary is greater than the salary of a professor and the university would get a team of 4 people to do the job – so it would really make sense to hire them. Of course the university could just pay a more reasonable salary for the president and hire an extra 3 professors. But the same argument applies for lots of highly paid jobs. Is a CEO who gets paid $10M per annim really going to do a better job than a team of 100 people who are paid $100K?

Joel on Software wrote an insightful article explaining why hiring 1/200 applicants doesn’t mean you hire the top 0.5% of workers [8]. He suggests that the best employees almost never apply through regular channels so an intern program is the only way to get a chance of hiring the best people.

Chaotic Idealism has an interesting article on some of the bogus claims about autism and violence [9].

Salon has an interesting articleby Lindsay Abrams about the way the food industry in the US lobbies for laws to prevent employees from reporting animal cruelty or contamination of the food supply and how drones will now be used for investigative journalism [10].

Jacobin Mag has an interesting article by Geoff Shullenberger about the “Voluntariat”, the people who volunteer their time to help commercial organisations [11]. I don’t object to people voluntarily helping companies, but when they are exploited or when the company also requires voluntary help from the government it becomes a problem. We need some legislation about this.

Laura Hudson wrote an insightful article about how Riot Games solved their online abuse problem [12]. There are ideas in this that can apply to all online communities.

Matt LeMay wrote an interesting article for Medium titled “What (Else) Can Men Do? Grow The Fuck Up” [13]. It’s a general commentary on the treatment of women in geek communities (and most other places).

Foz Meadows wrote an insightful analysis of the attempts of bigots to influence science-fiction [14]. If I had more spare time I’d read some of the books by bigoted authors on the “Sad Puppy Slate” (from a library of course) and see if they lack talent in the same way that Orson Scott Card does.

Racialicious has an interesting article by Phenderson Djeli Clark about the horrible racism and bigotry of H.P. Lovecraft [15]. I have only read two HP Lovecraft stories, one was mediocre and the other (The Horroe at Red Hook) was quite poor – largely due to his inability to write about non-white people.

Grace Wyler wrote an insightful article for Vice magazine about the right-wing terrorists in the US killing cops [16].

Paul Rosenberg wrote an interesting and amusing (for people outside the US) article about the gun crazies in the US [17]. Maybe the gun crazies should have a “loaded assault rifles and tequila” party to follow up on their “gun appreciation day”.

A US TV show made a 4 minute clip of some of the stupid things that Tony Abbott has done [18]. Tony is almost as stupid as Dubya.

Related posts:

  1. Links February 2014 The Economist has an interesting and informative article about the...
  2. Links May 2014 Charmian Gooch gave an interesting TED talk about her efforts...
  3. Links June 2013 Cory Doctorow published a letter from a 14yo who had...

Syndicated 2014-06-30 09:08:57 from etbe - Russell Coker

Fixing Strange Directory Write Access

type=AVC msg=audit(1403622580.061:96): avc:  denied  { write } for  pid=1331 comm="mysqld_safe" name="/" dev="dm-0" ino=256 scontext=system_u:system_r:mysqld_safe_t:s0 tcontext=system_u:object_r:root_t:s0 tclass=dir
type=SYSCALL msg=audit(1403622580.061:96): arch=c000003e syscall=269 success=yes exit=0 a0=ffffffffffffff9c a1=7f5e09bfe798 a2=2 a3=2 items=0 ppid=1109 pid=1331 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="mysqld_safe" exe="/bin/dash" subj=system_u:system_r:mysqld_safe_t:s0 key=(null)

For a long time (probably years) I’ve been seeing messages like the above in the log from auditd (/var/log/audit/audit.log) when starting mysqld. I haven’t fixed it because the amount of work exceeded the benefit, it’s just a couple of lines logged at every system boot. But today I decided to fix it.

The first step was to find out what was going on, I ran a test system in permissive mode and noticed that there were no attempts to create a file (that would have been easy to fix). Then I needed to discover which system call was triggering this. The syscall number is 269, the file linux/x86_64/syscallent.h in the strace source shows that 269 is the system call faccessat. faccessat(2) and access(2) are annoying cases, they do all the permission checks for access but don’t involve doing the operation so when a program uses those system calls but for some reason doesn’t perform the operation in question (in this case writing to the root directory) then we just get a log entry but nothing happening to examine.

A quick look at the shell script didn’t make the problem obvious, note that this is probably obvious to people who are more skilled at shell scripting than me – but it’s probably good for me to describe how to solve these problems every step of the way. So the next step was to use gdb. Here is the start of my gdb session:

# gdb /bin/sh
[skipped]
Reading symbols from /bin/dash…(no debugging symbols found)…done.
(gdb) b faccessat
Breakpoint 1 at 0×3960
(gdb) r -x /usr/bin/mysqld_safe
[lots skipped]
+ test -r /usr/my.cnf
Breakpoint 1, 0x00007ffff7b0c7e0 in faccessat ()
from /lib/x86_64-linux-gnu/libc.so.6

After running gdb on /bin/sh (which is a symlink to /bin/dash) I used the “b” command to set a breakpoint on the function faccessat (which is a library call from glibc that calls the system call sys_faccessat()). A breakpoint means that program execution will stop when the function is called. I run the shell script with “-x” as the first parameter to instruct the shell to show me the shell commands that are run so I can match shell commands to system calls. The above output shows the first call to faccessat() which isn’t interesting (it’s testing for read access).

I then ran the “c” command in gdb to continue execution and did so a few times until I found something interesting.

+ test -w / -o root = root
Breakpoint 1, 0x00007ffff7b0c7e0 in faccessat ()
from /lib/x86_64-linux-gnu/libc.so.6

Above is the interesting part of the gdb output. It shows that the offending shell command is “test -w /“.

I filed Debian bug #752593 [1] with a patch to fix this problem.

I also filed a wishlist bug against strace asking for an easier way to discover the name of a syscall [2].

Related posts:

  1. Tracking down Write/Execute mmap() calls with LD_PRELOAD One of the access controls in SE Linux is for...
  2. How not to write the way dumb people think smart people write Don Marti has written an amusing and informative little post...
  3. Fixing execmod (textrel) Problems in Lenny I’ve just updated my repository of SE Linux related packages...

Syndicated 2014-06-25 02:40:42 from etbe - Russell Coker

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