(If I've linked you to this page, it is my feeble attempt to provide a more convincing justification.)

I often receive instant messages or emails requesting help or guidance at work or on one of my various programming projects. When asked why they asked privately, the responses vary; mostly along the lines of it simply being an accident, not knowing where else to ask, as well as not wishing to "disturb" others with their bespoke question. Some will be more candid and simply admit that they were afraid of looking unknowledgable in front of others. It is always tempting to simply reply with the answer, especially as helping another human is inherently rewarding unless one is a psychopath. However, one can actually do more good overall by insisting the the question is re-asked in a more public forum.

---

This is for many reasons. Most obviously, public questions are simply far more efficient as soon as more than one person asks that question the response can be found in a search engine or linked to in the future. These time savings soon add up, meaning that simply more stuff can be done in any given day. After all, most questions are not as unique as people think. Secondly, a private communication cannot be corrected or elaborated on if someone else notices it is incorrect or incomplete. Even this rather banal point is more subtle that it first appears the lack of possible corrections deprives both the person asking and the person responding of the true and correct answer. Lastly, conversations that happen in private are depriving others of the answer as well. Perhaps someone was curious but hadn't got around to asking? Maybe the answer or even the question! contains a clue to solving some other issue. None of this can happen if this is occurs behind closed doors. (There are lots of subtler reasons too in a large organisation or team, simply knowing what other people are curious about can be curiously valuable information.)

---

Note that this is not as you might immediately suspect simply a way of ensuring that one gets the public recognition or "kudos" from being seen helping others. I wouldn't deny that technical communities work on a gift economy basis to some degree, but to attribute all acts of assistance as "selfish" and value-extracting would be to take the argument too far in the other direction. Saying that, the lure and appeal of public recognition should not be understated and can certainly provide an incentive to elaborate and provide a generally superior response. More philosophically, there's also something fundamentally "honest" about airing issues in an appropriately public and transparent manner. I feel it promotes a culture of egoless conversations, of being able to admit one's mistakes and ultimately a healthy personal mindset. So please, take care not only in the way you phrase and frame your question, but also consider wider context in which you are asking it. And don't take it too personally if I ask you to re-ask elsewhere...

Following the lead of my dear friend Daniel and his fantastic and addictive Summing up series, here s a link pack of recent stuff I read around the web. Link pack is definitely a terrible name, but I m working on it.

---

How to Silence Negative Thinking
On how to avoid the pitfall of being a Negatron and not an Optimist Prime. You might be your own worst enemy and you might not even know it:

Psychologists use the term automatic negative thoughts to describe the ideas that pop into our heads uninvited, like burglars, and leave behind a mess of uncomfortable emotions. In the 1960s, one of the founders of cognitive therapy, Aaron Beck, concluded that ANTs sabotage our best self, and lead to a vicious circle of misery: creating a general mindset that is variously unhappy or anxious or angry (take your pick) and which is (therefore) all the more likely to generate new ANTs. We get stuck in the same old neural pathways, having the same negative thoughts again and again.

Meet Harlem s Official Street Photographer
A man goes around Harlem with his camera, looking to give instead of taking. Makes you think about your approach to people and photography, things can be simpler. Kinda like Humans of New York, but in Harlem. And grittier, and on film but as touching, or more:

I tell people that my camera is a healing mechanism, Allah says. Let me photograph it and take it away from you.

What Happens When We Let Industry and Government Collect All the Data They Want
Why having nothing to hide is not about the now, but about the later. It s not that someone is going to judge for pushing every detail of your life to Twitter and Instagram, it s just that something you do might be illegal a few years later:

There was a time when it was essentially illegal to be gay. There was a time when it was legal to own people and illegal for them to run away. Sometimes, society gets it wrong. And it s not just nameless bureaucrats; it s men like Thomas Jefferson. When that happens, strong privacy protections including collection controls that let people pick who gets their data, and when allow the persecuted and unpopular to survive.

The Sex-Abuse Scandal Plaguing USA Swimming
Abusive coaches and a bullying culture in sports training are the perfect storm for damaging children. And it s amazing the extent to which a corporation or institution is willing to look the other way, as long as they save face. Very long piece, but intriguing to read. What Cities Would Look Like if Lit Only by the Stars
Thierry Cohen goes around the world and builds beautiful and realistic composite images of how would big cities look like if lit only by stars. The original page has some more cities: Villes teintes (Darkened Cities). On Muppets & Merchandise: How Jim Henson Turned His Art into a Business
Lessons from how Jim Henson managed to juggle both art and business without selling out for the wrong reasons. Really interesting, and reminds you to put Henson in perspective as a very smart man who managed to convince everyone to give him money for playing with muppets. The linked video on How the Muppet Show is Made is also cool. Made me curious enough to get the book. Barbie, Remixed: I (really!) can be a computer engineer
Mattel launched the most misguided book about empowering Barbie to be anything but a computer engineer in a book about being a computer engineer. The internet did not disappoint and fixed the problem within hours. There s now even an app for that (includes user submitted pages).

Earlier today, Josh send the text below to the R-SIG-Finance list, and I updated the R/Finance website, including its Call for Papers page, accordingly. We are once again very excited about our conference, thrilled about the four confirmed keynotes, and hope that many R / Finance users will not only join us in Chicago in May 2015 -- but also submit an exciting proposal. So read on below, and see you in Chicago in May! Call for Papers: R/Finance 2015: Applied Finance with R
May 29 and 30, 2015
University of Illinois at Chicago, IL, USA
The seventh annual R/Finance conference for applied finance using R will be held on May 29 and 30, 2015 in Chicago, IL, USA at the University of Illinois at Chicago. The conference will cover topics including portfolio management, time series analysis, advanced risk tools, high-performance computing, market microstructure, and econometrics. All will be discussed within the context of using R as a primary tool for financial risk management, portfolio construction, and trading. Over the past six years, R/Finance has included attendees from around the world. It has featured presentations from prominent academics and practitioners, and we anticipate another exciting line-up for 2015. This year will include invited keynote presentations by Emanuel Derman, Louis Marascio, Alexander McNeil, and Rishi Narang. We invite you to submit complete papers in pdf format for consideration. We will also consider one-page abstracts (in txt or pdf format) although more complete papers are preferred. We welcome submissions for both full talks and abbreviated "lightning talks." Both academic and practitioner proposals related to R are encouraged. All slides will be made publicly available at conference time. Presenters are strongly encouraged to provide working R code to accompany the slides. Data sets should also be made public for the purposes of reproducibility (though we realize this may be limited due to contracts with data vendors). Preference may be given to presenters who have released R packages. The conference will award two (or more) $1000 prizes for best papers. A submission must be a full paper to be eligible for a best paper award. Extended abstracts, even if a full paper is provided by conference time, are not eligible for a best paper award. Financial assistance for travel and accommodation may be available to presenters, however requests must be made at the time of submission. Assistance will be granted at the discretion of the conference committee. Please make your submission online at this link. The submission deadline is January 31, 2015. Submitters will be notified via email by February 28, 2015 of acceptance, presentation length, and financial assistance (if requested). Additional details will be announced via the R/Finance conference website as they become available. Information on previous years' presenters and their presentations are also at the conference website. For the program committee:

Gib Bassett, Peter Carl, Dirk Eddelbuettel, Brian Peterson, Dale Rosenthal,
Jeffrey Ryan, Joshua Ulrich

The Ubuntu Code of Conduct says:

Step down considerately: When somebody leaves or disengages from the project, we ask that they do so in a way that minimises disruption to the project. They should tell people they are leaving and take the proper steps to ensure that others can pick up where they left off.

I've been working on Ubuntu for over ten years now, almost right from the very start; I'm Canonical's employee #17 due to working out a notice period in my previous job, but I was one of the founding group of developers. I occasionally tell the story that Mark originally hired me mainly to work on what later became Launchpad Bugs due to my experience maintaining the Debian bug tracking system, but then not long afterwards Jeff Waugh got in touch and said "hey Colin, would you mind just sorting out some installable CD images for us?". This is where you imagine one of those movie time-lapse clocks ... At some point it became fairly clear that I was working on Ubuntu, and the bug system work fell to other people. Then, when Matt Zimmerman could no longer manage the entire Ubuntu team in Canonical by himself, Scott James Remnant and I stepped up to help him out. I did that for a couple of years, starting the Foundations team in the process. As the team grew I found that my interests really lay in hands-on development rather than in management, so I switched over to being the technical lead for Foundations, and have made my home there ever since. Over the years this has given me the opportunity to do all sorts of things, particularly working on our installers and on the GRUB boot loader, leading the development work on many of our archive maintenance tools, instituting the +1 maintenance effort and proposed-migration, and developing the Click package manager, and I've had the great pleasure of working with many exceptionally talented people. However. In recent months I've been feeling a general sense of malaise and what I've come to recognise with hindsight as the symptoms of approaching burnout. I've been working long hours for a long time, and while I can draw on a lot of experience by now, it's been getting harder to summon the enthusiasm and creativity to go with that. I have a wonderful wife, amazing children, and lovely friends, and I want to be able to spend a bit more time with them. After ten years doing the same kinds of things, I've accreted history with and responsibility for a lot of projects. One of the things I always loved about Foundations was that it's a broad church, covering a wide range of software and with a correspondingly wide range of opportunities; but, over time, this has made it difficult for me to focus on things that are important because there are so many areas where I might be called upon to help. I thought about simply stepping down from the technical lead position and remaining in the same team, but I decided that that wouldn't make enough of a difference to what matters to me. I need a clean break and an opportunity to reset my habits before I burn out for real. One of the things that has consistently held my interest through all of this has been making sure that the infrastructure for Ubuntu keeps running reliably and that other developers can work efficiently. As part of this, I've been able to do a lot of work over the years on Launchpad where it was a good fit with my remit: this has included significant performance improvements to archive publishing, moving most archive administration operations from excessively-privileged command-line operations to the webservice, making build cancellation reliable across the board, and moving live filesystem building from an unscalable ad-hoc collection of machines into the Launchpad build farm. The Launchpad development team has generally welcomed help with open arms, and in fact I joined the ~launchpad team last year. So, the logical next step for me is to make this informal involvement permanent. As such, at the end of this year I will be moving from Ubuntu Foundations to the Launchpad engineering team. This doesn't mean me leaving Ubuntu. Within Canonical, Launchpad development is currently organised under the Continuous Integration team, which is part of Ubuntu Engineering. I'll still be around in more or less the usual places and available for people to ask me questions. But I will in general be trying to reduce my involvement in Ubuntu proper to things that are closely related to the operation of Launchpad, and a small number of low-effort things that I'm interested enough in to find free time for them. I still need to sort out a lot of details, but it'll very likely involve me handing over project leadership of Click, drastically reducing my involvement in the installer, and looking for at least some help with boot loader work, among others. I don't expect my Debian involvement to change, and I may well find myself more motivated there now that it won't be so closely linked with my day job, although it's possible that I will pare some things back that I was mostly doing on Ubuntu's behalf. If you ask me for help with something over the next few months, expect me to be more likely to direct you to other people or suggest ways you can help yourself out, so that I can start disentangling myself from my current web of projects. Please contact me sooner or later if you're interested in helping out with any of the things I'm visible in right now, and we can see what makes sense. I'm looking forward to this!

I know I've been very quiet here lately. That's due to a variety of reasons, but mostly because settling in to a new job is taking nearly all of my attention and time. When that's combined with getting obsessed with watching the League of Legends world championships, it means no real time for writing things. I've had lots of time for reading things, though, and have a lot of book reviews that I need to write. So, of course, I felt like buying more books. Elizabeth Bear One-Eyed Jack (sff)
Steven Brust Hawk (sff)
Kenneth T. Jackson Crabgrass Frontier (non-fiction)
Ann Leckie Ancillary Sword (sff)
Scott Lynch Republic of Thieves (sff)
Randall Munroe What If? (non-fiction)
Sarah Tolmie The Stone Boatmen (sff)
Jeffrey Toobin The Oath (non-fiction) I'm pretty excited about everything in this shipment, but particularly the new Vlad Taltos novel from Brust and the sequel to Ancillary Justice (probably the best novel that I've read so far this year). And of course there's What If?.

As preannounced here the GNOME Infrastructure switched to a new Account Management System which is reachable at https://account.gnome.org. All the details will follow. Introduction It s been a while since someone actually touched the underlaying authentication infrastructure that powers the GNOME machines. The very first setup was originally configured by Jonathan Blandford (jrb) who configured an OpenLDAP istance with several customized schemas. (pServer fields in the old CVS days, pubAuthorizedKeys and GNOME modules related fields in recent times) While OpenLDAP-server was living on the GNOME machine called clipboard (aka ldap.gnome.org) the clients were configured to synchronize users, groups, passwords through the nslcd daemon. After several years Jeff Schroeder joined the Sysadmin Team and during one cold evening (date is Tue, February 1st 2011) spent some time configuring SSSD to replace the nslcd daemon which was missing one of the most important SSSD features: caching. What surely convinced Jeff to adopt SSSD (a very new but promising sofware at that time as the first release happened right before 2010 s Christmas) and as the commit log also states ( New sssd module for ldap information caching ) was SSSD s caching feature. It was enough for a certain user to log in once and the /var/lib/sss/db directory was populated with its login information preventing the LDAP daemon in charge of picking up login details (from the LDAP server) to query the LDAP server itself every single time a request was made against it. This feature has definitely helped in many occasions especially when the LDAP server was down for a particular reason and sysadmins needed to access a specific machine or service: without SSSD this wasn t ever going to work and sysadmins were probably going to be locked out from the machines they were used to manage. (except if you still had /etc/passwd , /etc/group and /etc/shadow entries as fallback) Things were working just fine except for a few downsides that appeared later on:

1. the web interface (view) on our LDAP user database was managed by Mango, an outdated tool which many wanted to rewrite in Django that slowly became a huge dinosaur nobody ever wanted to look into again
2. the Foundation membership information were managed through a MySQL database, so two databases, two sets of users unrelated to each other
3. users were not able to modify their own account information on their own but even a single e-mail change required them to mail the GNOME Accounts Team which was then going to authenticate their request and finally update the account.

Today s infrastructure changes are here to finally say the issues outlined at (1, 2, 3) are now fixed. What has changed? The GNOME Infrastructure is now powered by Red Hat s FreeIPA which bundles several FOSS softwares into one big bundle all surrounded by an easy and intuitive web UI that will help users update their account information on their own without the need of the Accounts Team or any other administrative entity. Users will also find two custom fields on their Overview page, these being Foundation Member since and Last Renewed on date . As you may have understood already we finally managed to migrate the Foundation membership database into LDAP itself to store the information we want once and for all. As a side note it might be possible that some users that were Foundation members in the past won t find any detail stored on the Foundation fields outlined above. That is actually expected as we were able to migrate all the current and old Foundation members that had an LDAP account registered at the time of the migration. If that s your case and you still would like the information to be stored on the new setup please get in contact with the Membership Committee at stating so. Where can I get my first login credentials? Let s make a little distinction between users that previously had access to Mango (usually maintainers) and users that didn t. If you were used to access Mango before you should be able to login on the new Account Management System by entering your GNOME username and the password you were used to use for loggin in into Mango. (after loggin in the very first time you will be prompted to update your password, please choose a strong password as this account will be unique across all the GNOME Infrastructure) If you never had access to Mango, you lost your password or the first time you read the word Mango on this post you thought why is he talking about a fruit now? you should be able to reset it by using the following command:

ssh -l yourgnomeuserid account.gnome.org

The command will start an SSH connection between you and account.gnome.org, once authenticated (with the SSH key you previously had registered on our Infrastructure) you will trigger a command that will directly send your brand new password on the e-mail registered for your account. From my tests seems GMail sees the e-mail as a phishing attempt probably because the body contains the word password twice. That said if the e-mail won t appear on your INBOX, please double-check your Spam folder. Now that Mango is gone how can I request a new account? With Mango we used to have a form that automatically e-mailed the maintainer of the selected GNOME module which was then going to approve / reject the request. From there and in the case of a positive vote from the maintainer the Accounts Team was going to create the account itself. With the recent introduction of a commit robot directly on l10n.gnome.org the number of account requests reduced its numbers. In addition to that users will now be able to perform pretty much all the needed maintenance on their accounts themselves. That said and while we will probably work on building a form in the future we feel that requesting accounts can definitely be achieved directly by mailing the Accounts Team itself which will mail the maintainer of the respective module and create the account. As just said the number of account creations has become very low and the queue is currently clear. The documentation has been updated to reflect these changes at: https://wiki.gnome.org/AccountsTeam
https://wiki.gnome.org/AccountsTeam/NewAccounts The migration of all the user data and ACLs has been massive and I ve been spending a lot of time reviewing the existing HBAC rules trying to spot possible errors or misconfigurations. If you happen to not being able to access a certain service as you were used to in the past, please get in contact with the Sysadmin Team. All the possible ways to contact us are available at https://wiki.gnome.org/Sysadmin/Contact. What is missing still? Now that the Foundation membership information has been moved to LDAP I ll be looking at porting some of the existing membership scripts to it. What I managed to port already are welcome e-mails for new or existing members. (renewals) Next step will be generating a membership page from LDAP (to populate http://www.gnome.org/foundation/membership) and all the your-membership-is-going-to-lapse e-mails that were being sent till today. Other news /home/users mount on master.gnome.org You will notice that loggin in into master.gnome.org will result in your home directory being empty, don t worry, you did not lose any of your files but master.gnome.org is now currently hosting your home directories itself. As you may have been aware of adding files to the public_html directory on master resulted in them appearing on your people.gnome.org/~userid space. That was unfortunately expected as both master and webapps2 (the machine serving people.gnome.org s webspaces) were mounting the same GlusterFS share. We wanted to prevent that behaviour to happen as we wanted to know who has access to what resource and where. From today master s home directories will be there just as a temporary spot for your tarballs, just scp and use ftpadmin against them, that should be all you need from master. If you are interested in receiving or keeping using your people.gnome.org s webspace please mail stating so. Other news a shiny and new error 500 page has been deployed Thanks to Magdalen Berns (magpie) a new error 500 web page has been deployed on all the Apache istances we host. The page contains an iframe of status.gnome.org and will appear every single time the web server behind the service you are trying to reach will be unreachable for maintenance or other purposes. While I hope you won t see the page that often you can still enjoy it at https://static.gnome.org/error-500/500.html. Make sure to whitelist status.gnome.org on your browser as it currently loads it without https. (as the service is currently hosted on OpenShift which provides us with a *.rhcloud.com wildcard certificate, which differs from the CN the browser would expect it to be)

As preannounced here the GNOME Infrastructure switched to a new Account Management System which is reachable at https://account.gnome.org. All the details will follow. Introduction It s been a while since someone actually touched the underlying authentication infrastructure that powers the GNOME machines. The very first setup was originally configured by Jonathan Blandford (jrb) who configured an OpenLDAP istance with several customized schemas. (pServer fields in the old CVS days, pubAuthorizedKeys and GNOME modules related fields in recent times) While OpenLDAP-server was living on the GNOME machine called clipboard (aka ldap.gnome.org) the clients were configured to synchronize users, groups, passwords through the nslcd daemon. After several years Jeff Schroeder joined the Sysadmin Team and during one cold evening (date is Tue, February 1st 2011) spent some time configuring SSSD to replace the nslcd daemon which was missing one of the most important SSSD features: caching. What surely convinced Jeff to adopt SSSD (a very new but promising sofware at that time as the first release happened right before 2010 s Christmas) and as the commit log also states ( New sssd module for ldap information caching ) was SSSD s caching feature. It was enough for a certain user to log in once and the /var/lib/sss/db directory was populated with its login information preventing the LDAP daemon in charge of picking up login details (from the LDAP server) to query the LDAP server itself every single time a request was made against it. This feature has definitely helped in many occasions especially when the LDAP server was down for a particular reason and sysadmins needed to access a specific machine or service: without SSSD this wasn t ever going to work and sysadmins were probably going to be locked out from the machines they were used to manage. (except if you still had /etc/passwd , /etc/group and /etc/shadow entries as fallback) Things were working just fine except for a few downsides that appeared later on:

1. the web interface (view) on our LDAP user database was managed by Mango, an outdated tool which many wanted to rewrite in Django that slowly became a huge dinosaur nobody ever wanted to look into again
2. the Foundation membership information were managed through a MySQL database, so two databases, two sets of users unrelated to each other
3. users were not able to modify their own account information on their own but even a single e-mail change required them to mail the GNOME Accounts Team which was then going to authenticate their request and finally update the account.

Today s infrastructure changes are here to finally say the issues outlined at (1, 2, 3) are now fixed. What has changed? The GNOME Infrastructure is now powered by Red Hat s FreeIPA which bundles several FOSS softwares into one big bundle all surrounded by an easy and intuitive web UI that will help users update their account information on their own without the need of the Accounts Team or any other administrative entity. Users will also find two custom fields on their Overview page, these being Foundation Member since and Last Renewed on date . As you may have understood already we finally managed to migrate the Foundation membership database into LDAP itself to store the information we want once and for all. As a side note it might be possible that some users that were Foundation members in the past won t find any detail stored on the Foundation fields outlined above. That is actually expected as we were able to migrate all the current and old Foundation members that had an LDAP account registered at the time of the migration. If that s your case and you still would like the information to be stored on the new setup please get in contact with the Membership Committee at stating so. Where can I get my first login credentials? Let s make a little distinction between users that previously had access to Mango (usually maintainers) and users that didn t. If you were used to access Mango before you should be able to login on the new Account Management System by entering your GNOME username and the password you were used to use for loggin in into Mango. (after loggin in the very first time you will be prompted to update your password, please choose a strong password as this account will be unique across all the GNOME Infrastructure) If you never had access to Mango, you lost your password or the first time you read the word Mango on this post you thought why is he talking about a fruit now? you should be able to reset it by using the following command:

ssh -l yourgnomeuserid account.gnome.org

The command will start an SSH connection between you and account.gnome.org, once authenticated (with the SSH key you previously had registered on our Infrastructure) you will trigger a command that will directly send your brand new password on the e-mail registered for your account. From my tests seems GMail sees the e-mail as a phishing attempt probably because the body contains the word password twice. That said if the e-mail won t appear on your INBOX, please double-check your Spam folder. Now that Mango is gone how can I request a new account? With Mango we used to have a form that automatically e-mailed the maintainer of the selected GNOME module which was then going to approve / reject the request. From there and in the case of a positive vote from the maintainer the Accounts Team was going to create the account itself. With the recent introduction of a commit robot directly on l10n.gnome.org the number of account requests reduced its numbers. In addition to that users will now be able to perform pretty much all the needed maintenance on their accounts themselves. That said and while we will probably work on building a form in the future we feel that requesting accounts can definitely be achieved directly by mailing the Accounts Team itself which will mail the maintainer of the respective module and create the account. As just said the number of account creations has become very low and the queue is currently clear. The documentation has been updated to reflect these changes at: https://wiki.gnome.org/AccountsTeam
https://wiki.gnome.org/AccountsTeam/NewAccounts I was used to have access to a specific service but I don t anymore, what should I do? The migration of all the user data and ACLs has been massive and I ve been spending a lot of time reviewing the existing HBAC rules trying to spot possible errors or misconfigurations. If you happen to not being able to access a certain service as you were used to in the past, please get in contact with the Sysadmin Team. All the possible ways to contact us are available at https://wiki.gnome.org/Sysadmin/Contact. What is missing still? Now that the Foundation membership information has been moved to LDAP I ll be looking at porting some of the existing membership scripts to it. What I managed to port already are welcome e-mails for new or existing members. (renewals) Next step will be generating a membership page from LDAP (to populate http://www.gnome.org/foundation/membership) and all the your-membership-is-going-to-lapse e-mails that were being sent till today. Other news /home/users mount on master.gnome.org You will notice that loggin in into master.gnome.org will result in your home directory being empty, don t worry, you did not lose any of your files but master.gnome.org is now currently hosting your home directories itself. As you may have been aware of adding files to the public_html directory on master resulted in them appearing on your people.gnome.org/~userid space. That was unfortunately expected as both master and webapps2 (the machine serving people.gnome.org s webspaces) were mounting the same GlusterFS share. We wanted to prevent that behaviour to happen as we wanted to know who has access to what resource and where. From today master s home directories will be there just as a temporary spot for your tarballs, just scp and use ftpadmin against them, that should be all you need from master. If you are interested in receiving or keeping using your people.gnome.org s webspace please mail <accounts AT gnome DOT org> stating so. Other news a shiny and new error 500 page has been deployed Thanks to Magdalen Berns (magpie) a new error 500 web page has been deployed on all the Apache istances we host. The page contains an iframe of status.gnome.org and will appear every single time the web server behind the service you are trying to reach will be unreachable for maintenance or other purposes. While I hope you won t see the page that often you can still enjoy it at https://static.gnome.org/error-500/500.html. Make sure to whitelist status.gnome.org on your browser as it currently loads it without https. (as the service is currently hosted on OpenShift which provides us with a *.rhcloud.com wildcard certificate, which differs from the CN the browser would expect it to be) Updates UPDATE on status.gnome.org s SSL certificate: the certificate has been provisioned and it should result in the 500 s page to be displayed correctly with no warnings from your browser. UPDATE from Adam Young on Kerberos ports being closed on many DC s firewalls:

The next version of upstream MIT Kerberos will have support for fetching a ticket via ports 443 and marshalling the request over HTTPS. We ll need to run a proxy on the server side, but we should be able to make it work: Read up here
http://adam.younglogic.com/2014/06/kerberos-firewalls

Another small new release of our BH package providing Boost headers for use by R is now on CRAN. This one brings a one-file change: the file any.hpp comprising the Boost.Any library --- as requested by a fellow package maintainer needing it for a pending upload to CRAN. No other changes were made.

Changes in version 1.54.0-4 (2014-08-29)

• Added Boost Any requested by Greg Jeffries for his nabo package

Courtesy of CRANberries, there is also a diffstat report for the most recent release. Comments and suggestions are welcome via the mailing list or issue tracker at the GitHub repo.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

Review: A People's History of the Supreme Court, by Peter Irons

Publisher:	Penguin
Copyright:	1999, 2006
Printing:	2006
ISBN:	0-14-303738-2
Format:	Trade paperback
Pages:	553

I first encountered Peter Irons via his Teaching Company course, The History of the Supreme Court. I listened to that and enjoyed it, and would recommend it as an excellent overview. When I later ran across this book, I was excited: I usually prefer books to lectures on topics that can benefit from greater depth, and A People's History of the United States is one of my favorite history books. A book that talked about the Supreme Court from a similar bottom-up approach was appealing. Unfortunately, I think the title oversells this book. It is a history of the Supreme Court, and, as with Zinn's book, it carries its bias openly (if not as forcefully or compellingly as Zinn). It is a legal history concerned with individual rights, and Irons openly expresses his opinions of the merits of certain decisions. But it's not the full-throated cry for justice and for the voice of the general population that Zinn's book was, nor did I think it entirely delivered on the introductory promise to look at the people and situations underlying the case. It does provide more background and biographical sketch of the litigants in famous cases than some other histories, but those sketches are generally brief and focused on the background and relevant facts for the case. This is, in short, a history of the Supreme Court, with some attention paid to the people involved and open comfort with an authorial viewpoint, but without the eye-opening and convention-defying freshness of Zinn's refusal to point the camera at the usual suspects. It also largely duplicates Irons's course for the Teaching Company. That's only really a problem for those, like me, who listened to that course already and came to this book looking for additional material. If you haven't listened to the course, this is a reasonable medium in which to provide the same content, although you do miss the audio recordings of actual Supreme Court argument in some of the most famous cases. But after having listened or read both, I think I prefer the course. It felt a bit more focused; the book is not padded, but the additional material is also not horribly memorable. That said, as a history, I found this a solid book. Irons opens with a surprisingly detailed look at the constitutional convention and the debates over the wording of the US Constitution, focusing on those sections that will become the heart of later controversy. Some of them were known to be controversial at the time and were discussed and argued at great length, such as anything related to slavery and the role of a bill of rights. But others, including many sections at the heart of modern controversies, were barely considered. Despite being a bit off-topic for the book, I found this section very interesting and am now wanting to seek out a good, full history of the convention. Irons's history from there is primarily chronological, although he does shift the order slightly to group some major cases into themes. He doesn't quite provide the biographies of each Supreme Court justice that he discussed in the introduction, but he comes close, along with discussion of the surrounding politics of the nomination and the political climate in which they were sitting. There's a bit of an overview of the types of cases each court saw, although not as much as I would have liked. Most of the history is, as one might expect, focused on more detailed histories of the major cases. Here, I was sometimes left satisfied and sometimes left a bit annoyed. The discussion of the Japanese internment cases is excellent, as you might expect given Irons's personal role in getting them overturned. The discussion of the segregation cases is also excellent; in general, I found Section V the strongest part of this book. Irons also does a good job throughout in showing how clearly political the court was and has always been, and the degree to which many major decisions were pre-decided by politics rather than reasoned legal judgment. Where I think he fails, however, is that much of this book has little sense of narrative arc. This is admittedly difficult in a history of a body that takes on widely varying and almost random cases, but there are some clear narratives that run through judicial thinking, and I don't think Irons does a good enough job telling those stories for the readers. For example, I remembered the evolution of interpretation of the 14th Amendment from freedom of contract to the keystone of application of the Bill of Rights to the states as a compelling and coherent story from his course, and here it felt scattered and less clear. In general, I liked the earlier sections of this book better than the later, with Section V on the Warren court as the best and last strong section. Beyond that point in the history, it felt like Irons was running out of steam, and it was harder and harder to see an underlying structure to the book. He would describe a few cases, in a factual but somewhat dry manner, make a few comments on the merits of the decision that felt more superficial than earlier sections of the book, and then move on to another case that might be largely unrelated. Recent judicial history is fascinating, but I don't think this is the book for that. Irons is much stronger in the 19th and first half of the 20th centuries; beyond that, I prefer Jeffrey Toobin's The Nine, which also has far deeper and more interesting biographies of recent justices. This is not a bad history of the Supreme Court. If you're looking for one, I can recommend it. But if you're flexible about format, I recommend Irons's course more. I think it's less dry, better presented, and flows better, and I don't feel like you'll miss much in the transformation of this book into an 18 hour course. It's also remarkable to hear the actual voices of the lawyers and justices in some of the landmark cases of the middle of the 20th century. But if you specifically want a book, this does the job. Do also read The Nine, though. It's a good complement to Irons's straight history, showing much more of the inner workings, political maneuverings, and day-to-day struggles of the justices. Rating: 7 out of 10

Background I ve previously written about the claim that people use Autism as an excuse for bad behavior [1]. In summary it doesn t and such claims instead lead to people not being assessed for Autism. I ve also previously written about empathy and Autism in the context of discussions about conference sexual harassment [2]. The main point is that anyone who s going to blame empathy disorders for the widespread mistreatment of women in society and divert the subject from the actions of average men to men in minority groups isn t demonstrating empathy. Discussions of the actions of average men are so often derailed to cover Autism that the Geek Feminism Wiki has a page about the issue of blaming Autism [3]. The Latest Issue Last year Shanley Kane wrote an informative article for Medium titled What Can Men Do about the treatment of women in the IT industry [4]. It s a good article, I recommend reading it. As an aside @shanley s twitter feed is worth reading [5]. In response to Shanley s article Jeff Atwood wrote an article of the same title this year which covered lots of other things [6]. He writes about Autism but doesn t seem to realise that officially Asperger Syndrome is now Autism according to DSM-V (they decided that separate diagnosis of Autism, Asperger Syndrome, and PDD-NOS were too difficult and merged them). Asperger Syndrome is now a term that refers to historic issues (IE research that was published before DSM-V) and slang use. Gender and the Autism Spectrum Jeff claims that autism skews heavily towards males at a 4:1 ratio and cites the Epidemiology of Autism Wikipedia page as a reference. Firstly that page isn t a great reference, I fixed one major error (which was obviously wrong to anyone who knows anything about Autism and also contradicted the cited reference) in the first section while writing this post. The Wikipedia page cites a PDF about the Epidemiology of Autism that claims the 4.3:1 ratio of boys to girls [7]. However that PDF is a summary of other articles and the one which originated the 4.3:1 claim is behind a paywall. One thing that is worth noting in the PDF is that the section containing the 4.3:1 claim also references claims about correlations between race and Autism and studies contradicting such claims it notes the possibility of ascertainment bias . I think that anyone who reads that section should immediately consider the possibility of ascertainment bias in regard to the gender ratio. Most people who are diagnosed with Autism are diagnosed as children. An Autism diagnosis of a child is quite subjective, an important part is an IQ test (where the psychologist interprets the intent of the child in the many cases where answers aren t clear) to compare social skills with IQ. So whether a child is diagnosed is determined by the psychologist s impression of the child s IQ vs the impression of their social skills. Whether a child is even taken for assessment depends on whether they act in a way that s considered to be obviously different. Any child who is suspected of being on the Autism Spectrum will be compared other children who have been diagnosed (IE mostly boys) and this will probably increase the probability that a boy will be assessed. So an Aspie girl might not be assessed because she acts like other Aspie girls not like the Aspie boys her parents and teachers have seen. The way kids act is not solely determined by neuro-type. Our society expects and encourages boys to be louder than girls and take longer and more frequent turns to speak, this is so widespread that I don t think it s possible for parents to avoid it if their kids are exposed to the outside world. Because of this boys who would be diagnosed with Asperger Syndrome by DSM-IV tend to act in ways that are obviously different from other kids. While the combination of Autism and the the social expectations on girls tends to result in girls who are quiet, shy, and apologetic. The fact that girls are less obviously different and that their differences cause fewer difficulties for parents and teachers makes them less likely to be assessed. Note that the differences in behavior of boys and girls who have been diagnosed is noted by the professionals (and was discussed at a conference on AsperGirls that my wife attended) while the idea that this affects assessment rates is my theory. Jeff also cites the book The Essential Difference: Male And Female Brains And The Truth About Autism by Professor Simon Baron-Cohen (who s (in)famous for his Extreme Male Brain theory). The first thing to note about the Extreme Male Brain theory are that it depends almost entirely on the 4.3:1 ratio of males to females on the Autism Spectrum (which is dubious as I noted above). The only other evidence in support of it is subjective studies of children which suffer from the same cultural issues this is why double blind tests should be used whenever possible. The book Delusions of Gender by Cordelia Fine [8] debunks Simon Baron-Cohen s work among other things. The look inside feature of the Amazon page for Delusions of Gender allows you to read about Simon Baron-Cohen s work [9]. Now even if the Extreme Male Brain theory had any merit it would be a really bad idea to cite it (or a book based on it) if you want to make things better for women in the IT industry. Cordelia s book debunks the science and also shows how such claims about supposed essential difference are taken as exclusionary. The Problem with Jeff Atwood Jeff suggests in his post that men should listen to women. Then he and his followers have a huge flame-war with many women over twitter during which which he tweeted Trying to diversify my follows by following any female voices that engaged me in a civil, constructive way recently . If you only listen to women who agree with you then that doesn t really count as listening to women. When you have a stated policy of only listening to women who agree then it seems to be more about limiting what women may feel free to say around you. The Geek Feminism wiki page about the Tone Argument [10] says the following: One way in which the tone argument frequently manifests itself is as a call for civility. A way to gauge whether a request for civility is sincere or not is to ask whether the person asking for civility has more power along whatever axes are contextually relevant (see Intersectionality) than the person being called incivil , less power, or equal power. Often, people who have the privilege of being listened to and taken seriously level accusations of incivility as a silencing tactic, and label as incivil any speech or behavior that questions their privilege. For example, some men label any feminist thought or speech as hostile or impolite; there is no way for anybody to question male power or privilege without being called rude or aggressive. Likewise, some white people label any critical discussion of race, particularly when initiated by people of color, as incivil. Writing about one topic is also a really good idea. A blog post titled What Can Men Do should be about things that men can do. Not about Autism, speculation about supposed inherent differences between men and women which are based on bad research, gender diversity in various occupations, etc. Following up a post on What Can Men Do with discussion (in blog comments and twitter) about what women should do before they are allowed to join the conversation is ridiculous. Jeff s blog post says that men should listen to women, excluding women based on the tone argument is gross hypocrisy. Swearing Jeff makes a big deal of the fact that Shanley uses some profane language in her tweets. This combines a couple of different ways of silencing women. It s quite common for women to be held to a high standard of ladylike behavior, while men get a free pass on doing the same thing. One example of this is the Geek Feminism article about the results of Sarah Sharp s request for civility in the Linux kernel community [11]. That s not an isolated incident, to the best of my recollection in 20+ years my local Linux Users Group has had only one debate about profanity on mailing lists in that case a woman (who is no longer active in the group) was criticised for using lesser profanity than men used both before and after with no comment (as an experiment I used some gratuitous profanity a couple of weeks later and no-one commented). There is also a common difference in interpretation of expressions of emotion, when a woman seems angry then she invariably has men tell her to change her approach (even when there are obvious reasons for her anger) while when a man is angry the possibility that other people shouldn t make him angry will usually be considered. The issues related to the treatment of women have had a large affect on Shanley s life and her friend s lives. It s quite understandable that she is angry about this. Her use of profanity in tweets seems appropriate to the situation. Other Links Newsweek s Gentlemen in Technology article has a section about Jeff [12], it s interesting to note his history of deleting tweets and editing his post. I presume he will change his post in response to mine and not make any note of the differences. Jacob Kaplan-Moss wrote a good rebuttal to Jeff s post [13]. It s a good article and has some other relevant links that are worth reading.

• [1] http://etbe.coker.com.au/2012/04/23/autism-as-an-excuse/
• [2] http://etbe.coker.com.au/2010/12/08/empathy-autism-and-geeks/
• [3] http://geekfeminism.wikia.com/wiki/Autism_is_to_blame
• [4] https://medium.com/tech-culture-briefs/a1e93d985af0
• [5] https://twitter.com/shanley
• [6] http://blog.codinghorror.com/what-can-men-do/
• [7] http://idea.library.drexel.edu/bitstream/1860/2632/1/2006175339.pdf
• [8] http://en.wikipedia.org/wiki/Delusions_of_Gender
• [9] http://www.amazon.com/Delusions-Gender-Society-Neurosexism-Difference/dp/0393340244
• [10] http://geekfeminism.wikia.com/wiki/Tone_argument
• [11] http://geekfeminism.org/2013/09/05/tone-policing-a-tool-for-protecting-male-power/
• [12] http://www.newsweek.com/today-tabs-meet-gentlemen-technology-248696
• [13] http://jacobian.org/writing/what-can-men-do/

For a while now, I have been looking for a sensible offsite backup solution for use at home. My requirements are simple, it must be cheap and locally encrypted (in other words, I keep the encryption keys, the storage provider do not have access to my private files). One idea me and my friends had many years ago, before the cloud storage providers showed up, was to use Google mail as storage, writing a Linux block device storing blocks as emails in the mail service provided by Google, and thus get heaps of free space. On top of this one can add encryption, RAID and volume management to have lots of (fairly slow, I admit that) cheap and encrypted storage. But I never found time to implement such system. But the last few weeks I have looked at a system called S3QL, a locally mounted network backed file system with the features I need. S3QL is a fuse file system with a local cache and cloud storage, handling several different storage providers, any with Amazon S3, Google Drive or OpenStack API. There are heaps of such storage providers. S3QL can also use a local directory as storage, which combined with sshfs allow for file storage on any ssh server. S3QL include support for encryption, compression, de-duplication, snapshots and immutable file systems, allowing me to mount the remote storage as a local mount point, look at and use the files as if they were local, while the content is stored in the cloud as well. This allow me to have a backup that should survive fire. The file system can not be shared between several machines at the same time, as only one can mount it at the time, but any machine with the encryption key and access to the storage service can mount it if it is unmounted. It is simple to use. I'm using it on Debian Wheezy, where the package is included already. So to get started, run apt-get install s3ql. Next, pick a storage provider. I ended up picking Greenqloud, after reading their nice recipe on how to use S3QL with their Amazon S3 service, because I trust the laws in Iceland more than those in USA when it come to keeping my personal data safe and private, and thus would rather spend money on a company in Iceland. Another nice recipe is available from the article S3QL Filesystem for HPC Storage by Jeff Layton in the HPC section of Admin magazine. When the provider is picked, figure out how to get the API key needed to connect to the storage API. With Greencloud, the key did not show up until I had added payment details to my account. Armed with the API access details, it is time to create the file system. First, create a new bucket in the cloud. This bucket is the file system storage area. I picked a bucket name reflecting the machine that was going to store data there, but any name will do. I'll refer to it as bucket-name below. In addition, one need the API login and password, and a locally created password. Store it all in ~root/.s3ql/authinfo2 like this:

[s3c]
storage-url: s3c://s.greenqloud.com:443/bucket-name
backend-login: API-login
backend-password: API-password
fs-passphrase: local-password

I create my local passphrase using pwget 50 or similar, but any sensible way to create a fairly random password should do it. Armed with these details, it is now time to run mkfs, entering the API details and password to create it:

# mkdir -m 700 /var/lib/s3ql-cache
# mkfs.s3ql --cachedir /var/lib/s3ql-cache --authfile /root/.s3ql/authinfo2 \
  --ssl s3c://s.greenqloud.com:443/bucket-name
Enter backend login: 
Enter backend password: 
Before using S3QL, make sure to read the user's guide, especially
the 'Important Rules to Avoid Loosing Data' section.
Enter encryption password: 
Confirm encryption password: 
Generating random encryption key...
Creating metadata tables...
Dumping metadata...
..objects..
..blocks..
..inodes..
..inode_blocks..
..symlink_targets..
..names..
..contents..
..ext_attributes..
Compressing and uploading metadata...
Wrote 0.00 MB of compressed metadata.
# 

The next step is mounting the file system to make the storage available.

# mount.s3ql --cachedir /var/lib/s3ql-cache --authfile /root/.s3ql/authinfo2 \
  --ssl --allow-root s3c://s.greenqloud.com:443/bucket-name /s3ql
Using 4 upload threads.
Downloading and decompressing metadata...
Reading metadata...
..objects..
..blocks..
..inodes..
..inode_blocks..
..symlink_targets..
..names..
..contents..
..ext_attributes..
Mounting filesystem...
# df -h /s3ql
Filesystem                              Size  Used Avail Use% Mounted on
s3c://s.greenqloud.com:443/bucket-name  1.0T     0  1.0T   0% /s3ql
#

The file system is now ready for use. I use rsync to store my backups in it, and as the metadata used by rsync is downloaded at mount time, no network traffic (and storage cost) is triggered by running rsync. To unmount, one should not use the normal umount command, as this will not flush the cache to the cloud storage, but instead running the umount.s3ql command like this:

# umount.s3ql /s3ql
# 

There is a fsck command available to check the file system and correct any problems detected. This can be used if the local server crashes while the file system is mounted, to reset the "already mounted" flag. This is what it look like when processing a working file system:

# fsck.s3ql --force --ssl s3c://s.greenqloud.com:443/bucket-name
Using cached metadata.
File system seems clean, checking anyway.
Checking DB integrity...
Creating temporary extra indices...
Checking lost+found...
Checking cached objects...
Checking names (refcounts)...
Checking contents (names)...
Checking contents (inodes)...
Checking contents (parent inodes)...
Checking objects (reference counts)...
Checking objects (backend)...
..processed 5000 objects so far..
..processed 10000 objects so far..
..processed 15000 objects so far..
Checking objects (sizes)...
Checking blocks (referenced objects)...
Checking blocks (refcounts)...
Checking inode-block mapping (blocks)...
Checking inode-block mapping (inodes)...
Checking inodes (refcounts)...
Checking inodes (sizes)...
Checking extended attributes (names)...
Checking extended attributes (inodes)...
Checking symlinks (inodes)...
Checking directory reachability...
Checking unix conventions...
Checking referential integrity...
Dropping temporary indices...
Backing up old metadata...
Dumping metadata...
..objects..
..blocks..
..inodes..
..inode_blocks..
..symlink_targets..
..names..
..contents..
..ext_attributes..
Compressing and uploading metadata...
Wrote 0.89 MB of compressed metadata.
# 

Thanks to the cache, working on files that fit in the cache is very quick, about the same speed as local file access. Uploading large amount of data is to me limited by the bandwidth out of and into my house. Uploading 685 MiB with a 100 MiB cache gave me 305 kiB/s, which is very close to my upload speed, and downloading the same Debian installation ISO gave me 610 kiB/s, close to my download speed. Both were measured using dd. So for me, the bottleneck is my network, not the file system code. I do not know what a good cache size would be, but suspect that the cache should e larger than your working set. I mentioned that only one machine can mount the file system at the time. If another machine try, it is told that the file system is busy:

# mount.s3ql --cachedir /var/lib/s3ql-cache --authfile /root/.s3ql/authinfo2 \
  --ssl --allow-root s3c://s.greenqloud.com:443/bucket-name /s3ql
Using 8 upload threads.
Backend reports that fs is still mounted elsewhere, aborting.
#

The file content is uploaded when the cache is full, while the metadata is uploaded once every 24 hour by default. To ensure the file system content is flushed to the cloud, one can either umount the file system, or ask S3QL to flush the cache and metadata using s3qlctrl:

# s3qlctrl upload-meta /s3ql
# s3qlctrl flushcache /s3ql
# 

If you are curious about how much space your data uses in the cloud, and how much compression and deduplication cut down on the storage usage, you can use s3qlstat on the mounted file system to get a report:

# s3qlstat /s3ql
Directory entries:    9141
Inodes:               9143
Data blocks:          8851
Total data size:      22049.38 MB
After de-duplication: 21955.46 MB (99.57% of total)
After compression:    21877.28 MB (99.22% of total, 99.64% of de-duplicated)
Database size:        2.39 MB (uncompressed)
(some values do not take into account not-yet-uploaded dirty blocks in cache)
#

I mentioned earlier that there are several possible suppliers of storage. I did not try to locate them all, but am aware of at least Greenqloud, Google Drive, Amazon S3 web serivces, Rackspace and Crowncloud. The latter even accept payment in Bitcoin. Pick one that suit your need. Some of them provide several GiB of free storage, but the prize models are quite different and you will have to figure out what suits you best. While researching this blog post, I had a look at research papers and posters discussing the S3QL file system. There are several, which told me that the file system is getting a critical check by the science community and increased my confidence in using it. One nice poster is titled "An Innovative Parallel Cloud Storage System using OpenStack s SwiftObject Store and Transformative Parallel I/O Approach" by Hsing-Bung Chen, Benjamin McClelland, David Sherrill, Alfred Torrez, Parks Fields and Pamela Smith. Please have a look. Given my problems with different file systems earlier, I decided to check out the mounted S3QL file system to see if it would be usable as a home directory (in other word, that it provided POSIX semantics when it come to locking and umask handling etc). Running my test code to check file system semantics, I was happy to discover that no error was found. So the file system can be used for home directories, if one chooses to do so. If you do not want a locally file system, and want something that work without the Linux fuse file system, I would like to mention the Tarsnap service, which also provide locally encrypted backup using a command line client. It have a nicer access control system, where one can split out read and write access, allowing some systems to write to the backup and others to only read from it. As usual, if you use Bitcoin and want to show your support of my activities, please send Bitcoin donations to my address 15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

The annoucement below just went to the R-SIG-Finance list. More information is as usual at the R / Finance page: See you in Chicago in May!

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

I love to say that Python is a nice subset of Lisp, and I discover that it's getting even more true as time passes. Recently, I've stumbled upon the PEP 443 that describes a way to dispatch generic functions, in a way that looks like what CLOS, the Common Lisp Object System, provides. What are generic functions If you come from the Lisp world, this won't be something new to you. The Lisp object system provides a really good way to define and handle method dispatching. It's a base of the Common Lisp object system. For my own pleasure to see Lisp code in a Python post, I'll show you how generic methods work in Lisp first. To begin, let's define a few very simple classes.
This defines a few classes: snare-drum, symbal, stick and brushes, without any parent class nor attribute. These classes compose a drum kit, and we can combine them to play sound. So we define a play method that takes two arguments, and returns a sound (as a string).
This only defines a generic method: it has no body, and cannot be called with any instance yet. At this stage, we only inform the object system that the method is generic and can be then implemented with various type of arguments. We'll start by implementing versions of this method that knows how to play with the snare-drum.
Now we just defined concrete methods with code. They also takes two arguments: instrument which is an instance of snare-drum and accessory that is an instance of stick or brushes. At this stage, you should note the first difference with object system as built into language like Python: the method isn't tied to any class in particular. The methods are generic, and any class can implement them, or not. Let's try it.
As you see, the function called depends on the class of the arguments. The object systems dispatch the function calls to the right function for us, depending on the arguments classes. If we call play with instances that are not know to the object system, an error will be thrown. Inheritance is also supported and the equivalent (but more powerful and less error prone) equivalent of Python's super() is available via (call-next-method).
In this example, we define the stick and brushes classes as subclass of the accessory class. The play method defined will return the sound BIIING! regardless of the accessory instance that is used to play the cymbal. Except in the case where it's a brushes instance; only the most precise method is always called. The (call-next-method) function is used to call the closest parent method, in this case that would be the method returning _"BIIING!".
Note that CLOS is also able to dispatch on object instances themself by using the eql specializer. But if you're really curious about all features CLOS provides, I suggest you read the brief guide to CLOS by Jeff Dalton as a starter. Python implementation Python implements a simpler equivalence of this workflow with the singledispatch function. It will be provided with Python 3.4 as part of the functools module. Here's a rough equivalence of the above Lisp program.
We define our four classes, and a base play function that raises NotImplementedError, indicating that by default we don't know what to do. We can then write specialized version of this function with a first instrument, the SnareDrum. We then check for the accessory type that we get, and return the appropriate sound or raise NotImplementedError again if we don't know what to do with it. If we run it, it works as expected:
The singledispatch module looks through the classes of the first argument passed to the play function, and calls the right version of it. The first defined version of the play function is always run for the object class, so if our instrument is a class that we did not register for, this base function will be called. For whose eager to try and use it, the singledispatch function is provided Python 2.6 to 3.3 through the Python Package Index. Limitations First, as you noticed in the Lisp version, CLOS provides a multiple dispatcher that can dispatch on the type of any of the argument defined in the method prototype, not only the first one. Unfortunately, Python dispatcher is named singledispatch for this good reason: it only knows to dispatch on the first argument. Guido van Rossum wrote a short article about the subject that he called multimethod a few years ago. Then, there's no way to call the parent function directly. There's no equivalent of the (call-next-method) from Lisp nor the super() function that allows to do that in Python class system. This means you will have to use various trick to bypass this limitation. So while I am really glad that Python is going toward that direction, as it's a really powerful way to enhance an object system, it really lacks a lot of more advanced features that CLOS provides out of the box. Though, improving this could be an interesting challenge. Especially to bring more CLOS power to Hy. :-)

This morning I made a new release of Lumail, which recently completed the transition from using mimetic to GMime for all its MIME needs. I was happy with mimetic, except it didn't have the facility to decode encoded header-values. I wrote some code, but it was broken, so I made the decision that we should move to something that made this easier, and GMime was chosen. Jeffrey Stedfast was very helpful in answering my questions with near-perfect code samples. Beyond that this release features some more Lua primitives and a couple of bug-fixes. The only annoyance is that the version of GMime I'm using, 2.6.x, isn't available to users of the Squeeze release of Debian GNU/Linux. It is available as a backport, but that means building binaries with sbuild is a pain - due to #700522. So for the moment I've only built binaries for Wheezy users. ObQuote: "You know who I am, I've not been off TV for that long!" - Alan Patridge, Alpha Papa

I have attended the SciPy 2013 conference in Austin, Texas. Here are my impressions.

Number one is the fact that the IPython notebook was used by pretty much everyone. I use it a lot myself, but I didn't realize how ubiquitous it has become. It is quickly becoming the standard now. The IPython notebook is using Markdown and in fact it is better than Rest. The way to remember the "[]()" syntax for links is that in regular text you put links into () parentheses, so you do the same in Markdown, and append [] for the text of the link. The other way to remember is that [] feel more serious and thus are used for the text of the link. I stressed several times to +Fernando Perez and +Brian Granger how awesome it would be to have interactive widgets in the notebook. Fortunately that was pretty much preaching to the choir, as that's one of the first things they plan to implement good foundations for and I just can't wait to use that.

It is now clear, that the IPython notebook is the way to store computations that I want to share with other people, or to use it as a "lab notebook" for myself, so that I can remember what exactly I did to obtain the results (for example how exactly I obtained some figures from raw data). In other words --- instead of having sets of scripts and manual bash commands that have to be executed in particular order to do what I want, just use IPython notebook and put everything in there.
Number two is that how big the conference has become since the last time I attended (couple years ago), yet it still has the friendly feeling. Unfortunately, I had to miss a lot of talks, due to scheduling conflicts (there were three parallel sessions), so I look forward to seeing them on video.

+Aaron Meurer and I have done the SymPy tutorial (see the link for videos and other tutorial materials). It's been nice to finally meet +Matthew Rocklin (very active SymPy contributor) in person. He also had an interesting presentation
about symbolic matrices + Lapack code generation. +Jason Moore presented PyDy.
It's been a great pleasure for us to invite +David Li (still a high school student) to attend the conference and give a presentation about his work on sympygamma.com and live.sympy.org.

It was nice to meet the Julia guys, +Jeff Bezanson and +Stefan Karpinski. I contributed the Fortran benchmarks on the Julia's website some time ago, but I had the feeling that a lot of them are quite artificial and not very meaningful. I think Jeff and Stefan confirmed my feeling. Julia seems to have quite interesting type system and multiple dispatch, that SymPy should learn from.

I met the VTK guys +Matthew McCormick and +Pat Marion. One of the keynotes was given by +Will Schroeder from Kitware about publishing. I remember him stressing to manage dependencies well as well as to use BSD like license (as opposed to viral licenses like GPL or LGPL). That opensource has pretty much won (i.e. it is now clear that that is the way to go).

I had great discussions with +Francesc Alted, +Andy Terrel, +Brett Murphy, +Jonathan Rocher, +Eric Jones, +Travis Oliphant, +Mark Wiebe, +Ilan Schnell, +St fan van der Walt, +David Cournapeau, +Anthony Scopatz, +Paul Ivanov, +Michael Droettboom, +Wes McKinney, +Jake Vanderplas, +Kurt Smith, +Aron Ahmadia, +Kyle Mandli, +Benjamin Root and others.


It's also been nice to have a chat with +Jason Vertrees and other guys from Schr dinger.

One other thing that I realized last week at the conference is that pretty much everyone agreed on the fact that NumPy should act as the default way to represent memory (no matter if the array was created in Fortran or other code) and allow manipulations on it. Faster libraries like Blaze or ODIN should then hook themselves up into NumPy using multiple dispatch. Also SymPy would then hook itself up so that it can be used with array operations natively. Currently SymPy does work with NumPy (see our tests for some examples what works), but the solution is a bit fragile (it is not possible to override NumPy behavior, but because NumPy supports general objects, we simply give it SymPy objects and things mostly work).

Similar to this, I would like to create multiple dispatch in SymPy core itself, so that other (faster) libraries for symbolic manipulation can hook themselves up, so that their own (faster) multiplication, expansion or series expansion would get called instead of the SymPy default one implemented in pure Python.

Other blog posts from the conference:

• Aaron's post
• Fernando's post