Direct harassment and overt sexism are certainly a significant part of why the gender ratios in the Linux community[1] are so skewed, but they're not the whole story. Part of feeling comfortable with a community is the knowledge that those in positions of power can be relied upon to engage in appropriate action when undesirable situations arise - no matter how compelling your code of conduct, no matter how detailed your diversity policy, if someone contravenes them and nothing happens, those documents are worthless and your community is unwelcoming. You can't rely on enforcement unless the community can trust its leadership.

Setting a good example in terms of behaviour is obviously vital, but it's not sufficient. Leaders who engage in sexist behaviour or who harass community members are clearly untrustworthy and undermine any attempts the rest of the community may be making. Failing to step in when they see examples of unacceptable behaviour is as bad. But less obvious is that it's possible to destroy that community trust without clearly contravening those community standards.

An example of this is Todd Akin, a candidate for the upcoming US Senate elections. In August he justified his support for making abortion illegal even in cases of rape, on the basis that women can't become pregnant through being victims of "legitimate rape". Of course, this had little to do with his fiscal or wider social policies, positions that are more directly relevant to most of his potential constituents, and in an election year that's primarily about the economy and healthcare it might be expected that a single issue would have little effect on the election standings. Instead, there was a huge uproar and a previously safe victory has now turned into a real chance of a loss.

Why? A significant part of it is because many people now have difficulty believing that they can trust him to represent them. If he understands women so little that he's willing to make entirely spurious justifications for his positions, how could any woman trust him to consider any other problems they may face? If he's willing to use fake science to back himself up, how could anyone trust him to consider any issue involving science? Through a single statement to a journalist he demonstrated to many that he was unsuited to be their representative in government. Many people who would otherwise have voted for him simply don't feel that they can rely on him to be there for them. Whether he wins his election or not, that distrust is going to remain and it's going to compromise his ability to work with his constituents.

It's the same in technical communities. If a member of a project's technical leadership frequently and loudly expresses their disdain for Python coders, anyone advocating for increased use of Python in that project is unlikely to feel that they can get unbiased opinions from that leader. If the project as a whole is uninterested in adopting Python then that's probably for the best, but if the rest of the project is open to using Python then there's a problem. People working with Python are less likely to join the project, and perhaps the project will lose out as a result.

But it's worth remembering that technical communities are still communities. If a member of a project's technical leadership vociferously argues that slavery benefited minority groups in the long run, members of those minority groups are going to feel that they're not going to be well represented by that leader. If they blog about how homosexuality is a lifestyle choice then homosexuals are unlikely to flock to the project. Likewise, if they downplay the prevalence or impact of rape, women are going to feel marginalised and find something better to do with their time.

It's impossible to separate these things. No matter how technically competent a community leader is, no matter how much code review they perform or how much mentorship they provide, if they're expressing unacceptable social opinions then they're diminishing the community. People I know and respect have left technical communities simply because people in positions of responsibility have engaged in this kind of behaviour without it causing them any problems.

We shouldn't be willing to give people a pass simply because they aren't actually groping anyone or because they're not members of the KKK. Those who drive people away from the community on the basis of race, gender or sexual orientation deserve vocal condemnation, and if they're unwilling to change their behaviour then the community should instead act to drive them away.

We're pretty bad at that in the Linux world at the moment. Too many people have behaved in this way and are left with positions of power or responsibility. There's no easy solution to the problem, but the Ada Initiative is continuing to work to improve awareness and work with communities to reduce the alienation that results from this kind of behaviour. If you want this to be anything other than a straight white male dominated community, you should give them money.

[1] (and computing in general, though to a lesser extent)

comments

I believe I'm not the only one who thinks that use case oriented Grub2 documentation is hard to find, and a lot of the documentation is obsolete or wrong. My main cause for writing this blog post is a currently unanswered question regarding 2.00, but meanwhile it seems months have passed and still most 1.99 documentation is wrong as well, which might be interesting to some.

The aim is to prevent grub entries from being edited, while not restricting actual booting. This protection is meant for computers not having any confidential stuff, but just wanting to do some light weight security with the assumption that the computer isn't physically opened.

Common setup

You will obviously want to disable any automatically generated root access giving entries, by for example uncommenting GRUB_DISABLE_RECOVERY="true" in /etc/default/grub on Debian or Ubuntu. Also you would disable allowing any external boot devices to be used in BIOS/EFI/coreboot, which you would also have protected with a password. And that often means you need to also disable USB legacy support, since some BIOSes tend to offer all USB devices as bootable without password otherwise (note that I guess that could also cause problems accessing setup on desktop computers if your only keyboard is USB).

1.99

So to first fix the false instructions in various places - no, setting the superuser in 00_header as instructed is not enough. It might be, but does not apply if eg. old kernels are put into submenu (Ubuntu bug 718670, Fedora bug 836259). The protection from editing does not apply there. And if you remove all but one kernel so that there is no submenu, a submenu will be automatically created when there is a new kernel installed via security updates. I didn't need the submenu feature anyway, so I used to comment out the following lines in /etc/grub.d/10_linux:

#if [ "$list" ] && ! $in_submenu; then
#echo "submenu \"Previous Linux versions\" "
#in_submenu=:
#fi

...

#if $in_submenu; then
# echo " "
#fi

I hope that was useful. I can imagine it causing a couple of family battles if the commonly instructed setup was the only protection used and there's for example a case of two computer savvy siblings that are eager to get to each others' computers...

2.00 & The Question

The problem with 2.00 is that the superusers setup yields a non-bootable system, ie. password is required for booting. But Google wasn't smiling at me today! Terrible. Can you help me (and others) with 2.00? The aim would be to have a 1.99-like setup where superuser password protects all entries from editing, but booting is fine without any passwords.

Update: Thanks, problem solved, see comments! Find the following line in /etc/grub.d/10_linux:

echo "menuentry '$(echo "$os" grub_quote)' $ CLASS \$menuentry_id_option 'gnulinux-simple-$boot_device_id' " sed "s/^/$submenu_indentation/"

And add --unrestricted there. Don't mix the line with the another menuentry line two lines earlier. The submenu problem doesn't exist anymore in 2.00.

FD passing for DRI.Next Using the DMA-BUF interfaces to pass DRI objects between the client and server, as discussed in my previous blog posting on DRI-Next, requires that we successfully pass file descriptors over the X protocol socket. Rumor has it that this has been tried and found to be difficult, and so I decided to do a bit of experimentation to see how this could be made to work within the existing X implementation. (All of the examples shown here are licensed under the GPL, version 2 and are available from git://keithp.com/git/fdpassing) Basics of FD passing The kernel internals that support FD passing are actually quite simple POSIX already require that two processes be able to share the same underlying reference to a file because of the semantics of the fork(2) call. Adding some ability to share arbitrary file descriptors between two processes then is far more about how you ask the kernel than the actual file descriptor sharing operation. In Linux, file descriptors can be passed through local network sockets. The sender constructs a mystic-looking sendmsg(2) call, placing the file descriptor in the control field of that operation. The kernel pulls the file descriptor out of the control field, allocates a file descriptor in the target process which references the same file object and then sticks the file descriptor in a queue for the receiving process to fetch. The receiver then constructs a matching call to recvmsg that provides a place for the kernel to stick the new file descriptor. A helper API for testing I first write a stand-alone program that created a socketpair, forked and then passed an fd from the parent to the child. Once that was working, I decided that some short helper functions would make further testing a whole lot easier. Here s a function that writes some data and an optional file descriptor:

ssize_t
sock_fd_write(int sock, void *buf, ssize_t buflen, int fd)
 
    ssize_t     size;
    struct msghdr   msg;
    struct iovec    iov;
    union  
        struct cmsghdr  cmsghdr;
        char        control[CMSG_SPACE(sizeof (int))];
      cmsgu;
    struct cmsghdr  *cmsg;
    iov.iov_base = buf;
    iov.iov_len = buflen;
    msg.msg_name = NULL;
    msg.msg_namelen = 0;
    msg.msg_iov = &iov;
    msg.msg_iovlen = 1;
    if (fd != -1)  
        msg.msg_control = cmsgu.control;
        msg.msg_controllen = sizeof(cmsgu.control);
        cmsg = CMSG_FIRSTHDR(&msg);
        cmsg->cmsg_len = CMSG_LEN(sizeof (int));
        cmsg->cmsg_level = SOL_SOCKET;
        cmsg->cmsg_type = SCM_RIGHTS;
        printf ("passing fd %d\n", fd);
        *((int *) CMSG_DATA(cmsg)) = fd;
      else  
        msg.msg_control = NULL;
        msg.msg_controllen = 0;
        printf ("not passing fd\n");
     
    size = sendmsg(sock, &msg, 0);
    if (size < 0)
        perror ("sendmsg");
    return size;
 

And here s the matching receiver function:

ssize_t
sock_fd_read(int sock, void *buf, ssize_t bufsize, int *fd)
 
    ssize_t     size;
    if (fd)  
        struct msghdr   msg;
        struct iovec    iov;
        union  
            struct cmsghdr  cmsghdr;
            char        control[CMSG_SPACE(sizeof (int))];
          cmsgu;
        struct cmsghdr  *cmsg;
        iov.iov_base = buf;
        iov.iov_len = bufsize;
        msg.msg_name = NULL;
        msg.msg_namelen = 0;
        msg.msg_iov = &iov;
        msg.msg_iovlen = 1;
        msg.msg_control = cmsgu.control;
        msg.msg_controllen = sizeof(cmsgu.control);
        size = recvmsg (sock, &msg, 0);
        if (size < 0)  
            perror ("recvmsg");
            exit(1);
         
        cmsg = CMSG_FIRSTHDR(&msg);
        if (cmsg && cmsg->cmsg_len == CMSG_LEN(sizeof(int)))  
            if (cmsg->cmsg_level != SOL_SOCKET)  
                fprintf (stderr, "invalid cmsg_level %d\n",
                     cmsg->cmsg_level);
                exit(1);
             
            if (cmsg->cmsg_type != SCM_RIGHTS)  
                fprintf (stderr, "invalid cmsg_type %d\n",
                     cmsg->cmsg_type);
                exit(1);
             
            *fd = *((int *) CMSG_DATA(cmsg));
            printf ("received fd %d\n", *fd);
          else
            *fd = -1;
      else  
        size = read (sock, buf, bufsize);
        if (size < 0)  
            perror("read");
            exit(1);
         
     
    return size;
 

With these two functions, I rewrote the simple example as follows:

void
child(int sock)
 
    int fd;
    char    buf[16];
    ssize_t size;
    sleep(1);
    for (;;)  
        size = sock_fd_read(sock, buf, sizeof(buf), &fd);
        if (size <= 0)
            break;
        printf ("read %d\n", size);
        if (fd != -1)  
            write(fd, "hello, world\n", 13);
            close(fd);
         
     
 
void
parent(int sock)
 
    ssize_t size;
    int i;
    int fd;
    fd = 1;
    size = sock_fd_write(sock, "1", 1, 1);
    printf ("wrote %d\n", size);
 
int
main(int argc, char **argv)
 
    int sv[2];
    int pid;
    if (socketpair(AF_LOCAL, SOCK_STREAM, 0, sv) < 0)  
        perror("socketpair");
        exit(1);
     
    switch ((pid = fork()))  
    case 0:
        close(sv[0]);
        child(sv[1]);
        break;
    case -1:
        perror("fork");
        exit(1);
    default:
        close(sv[1]);
        parent(sv[0]);
        break;
     
    return 0;
 

Experimenting with multiple writes I wanted to know what would happen if multiple writes were made, some with file descriptors and some without. So I changed the simple example parent function to look like:

void
parent(int sock)
 
    ssize_t size;
    int i;
    int fd;
    fd = 1;
    size = sock_fd_write(sock, "1", 1, -1);
    printf ("wrote %d without fd\n", size);
    size = sock_fd_write(sock, "1", 1, 1);
    printf ("wrote %d with fd\n", size);
    size = sock_fd_write(sock, "1", 1, -1);
    printf ("wrote %d without fd\n", size);
 

When run, this demonstrates that the reader gets two bytes in the first read along with a file descriptor followed by one byte in a second read, without a file descriptor. This demonstrates that a file descriptor message forms a barrier within the socket; multiple messages will be merged together, but not past a message containing a file descriptor. Reading without accepting a file descriptor What happens when the reader isn t expecting a file descriptor? Does it just get lost? Does the reader not get the message until it asks for the file descriptor? What about the boundary issue described above? Here s my test case:

void
child(int sock)
 
    int fd;
    char    buf[16];
    ssize_t size;
    sleep(1);
    size = sock_fd_read(sock, buf, sizeof(buf), NULL);
    if (size <= 0)
        return;
    printf ("read %d\n", size);
    size = sock_fd_read(sock, buf, sizeof(buf), &fd);
    if (size <= 0)
        return;
    printf ("read %d\n", size);
    if (fd != -1)  
        write(fd, "hello, world\n", 13);
        close(fd);
     
 
void
parent(int sock)
 
    ssize_t size;
    int i;
    int fd;
    fd = 1;
    size = sock_fd_write(sock, "1", 1, 1);
    printf ("wrote %d without fd\n", size);
    size = sock_fd_write(sock, "1", 1, 2);
    printf ("wrote %d with fd\n", size);
 

This shows that the first passed file descriptor is picked up by the first sockfdread call, but the file descriptor is closed. The second file descriptor passed is picked up by the second sockfdread call. Zero-length writes Can a file descriptor be passed without sending any data?

void
parent(int sock)
 
    ssize_t size;
    int i;
    int fd;
    fd = 1;
    size = sock_fd_write(sock, "1", 1, -1);
    printf ("wrote %d without fd\n", size);
    size = sock_fd_write(sock, NULL, 0, 1);
    printf ("wrote %d with fd\n", size);
    size = sock_fd_write(sock, "1", 1, -1);
    printf ("wrote %d without fd\n", size);
 

And the answer is clearly no the file descriptor is not passed when no data are included in the write. A summary of results

1. read and recvmsg don t merge data across a file descriptor message boundary.
2. failing to accept an fd in the receiver results in the fd being closed by the kernel.
3. a file descriptor must be accompanied by some data.

Make X pass file descriptors I d like to get X to pass a file descriptor without completely rewriting the internals of both the library and the X server. Ideally, without making any changes to the existing code paths for regular request processing at all. On the sending side, this seems pretty straightforward we just need to get the X connection file descriptor and call sendmsg directly, passing the desired file descriptor along. In XCB, this could be done by using the xcbtakesocket interface to temporarily hijack the protocol as Xlib does. It s the receiving side where things are messier. Because a bare read will discard any delivered file descriptor, we must make sure to use recvmsg whenever we want to actually capture the file descriptor. Kludge X server fd receiving Because a passed fd creates a barrier in the bytestream, when the X server reads requests from a client, the read will stop sending data after the message with the file descriptor is consumed. Of course, this process consumes the passed file descriptor, and if that call isn t made with recvmsg set up to receive it, the fd will be lost. As a simple kludge, if we pass a meaningless fd with the X request and then the real fd with a following XNoOperation request, the existing request reading code will get the request, discard the meaningless fd and then stop reading at that point due to the barrier. Once into the request processing code, recvmsg can be called to get the real file descriptor and the associated XNoOperation request. I wrote a test for this that demonstrates how this works:

static void
child(int sock)
 
    uint8_t xreq[1024];
    uint8_t xnop[4];
    uint8_t req;
    int i, reqlen;
    ssize_t size, fdsize;
    int fd = -1, *fdp;
    int j;
    sleep (1);
    for (j = 0;; j++)  
        size = sock_fd_read(sock, xreq, sizeof (xreq), NULL);
        printf ("got %d\n", size);
        if (size == 0)
            break;
        i = 0;
        while (i < size)  
            req = xreq[i];
            reqlen = xreq[i+1];
            i += reqlen;
            switch (req)  
            case 0:
                break;
            case 1:
                if (i != size)  
                    fprintf (stderr, "Got fd req, but not at end of input %d < %d\n",
                         i, size);
                 
                fdsize = sock_fd_read(sock, xnop, sizeof (xnop), &fd);
                if (fd == -1)  
                    fprintf (stderr, "no fd received\n");
                  else  
                    FILE    *f = fdopen (fd, "w");
                    fprintf(f, "hello %d\n", j);
                    fflush(f);
                    fclose(f);
                    close(fd);
                    fd = -1;
                 
                break;
            case 2:
                fprintf (stderr, "Unexpected FD passing req\n");
                break;
             
         
     
 
int
tmp_file(int j)  
    char    name[64];
    sprintf (name, "tmp-file-%d", j);
    return creat(name, 0666);
 
static void
parent(int sock)
 
    uint8_t xreq[32];
    uint8_t xnop[4];
    int i, j;
    int fd;
    for (j = 0; j < 4; j++)  
        /* Write a bunch of regular requests */
        for (i = 0; i < 8; i++)  
            xreq[0] = 0;
            xreq[1] = sizeof (xreq);
            sock_fd_write(sock, xreq, sizeof (xreq), -1);
         
        /* Write our 'pass an fd' request with a 'useless' FD to block the receiver */
        xreq[0] = 1;
        xreq[1] = sizeof(xreq);
        sock_fd_write(sock, xreq, sizeof (xreq), 1);
        /* Pass an fd */
        xnop[0] = 2;
        xnop[1] = sizeof (xnop);
        fd = tmp_file(j);
        sock_fd_write(sock, xnop, sizeof (xnop), fd);
        close(fd);
     
 

Fixing XCB to receive file descriptors Multiple threads may be trying to get replies and events back from the X server at the same time, which means the kludge of having the real fd follow the message will likely lead to the wrong thread getting the file descriptor. Instead, I suspect the best plan will be to fix XCB to internally capture passed file descriptors and save them with the associated reply. Because the file descriptor message will form a barrier in the read stream, xcb can associate any received file descriptor with the last reply in the read data. The X server would then send the reply with an explicit sendmsg call to pass both reply and file descriptor together. Next steps The next thing to do is code up a simple fd passing extension and try to get it working, passing descriptors back and forth to the X server. Once that works, design of the rest of the DRM-Next extension should be pretty straightforward.

It was a surprisingly busy week. The commit notification service CIA was shut down about a week ago, so I spammedsent some messages to announce that KGB could be used as a replacement, and Don Armstrong wrote a great tutorial on how to set it up. As a result, many people came to us to use our bots, or to set-up their own instances. Since then, 14 Debian sub-projects started using our bots, and we know of at least two other bots being run independently. For a small project that was mainly developed and maintained for our own use, this was quite some unexpected popularity! With bug reports and feature requests starting to flow in, Damyan Ivanov (who's basically the one doing most of the work these days) sat down and produced a new release. So, I present you, KGB 1.16! What's new

• Added support for CVS.
• Ability to pass a commit URL along with the commit, to provide a direct link to the change-set. This requires both client and server to be updated.
• Some changes in the colour-scheme.
• A new script, kgb-add-project, eases the addition of new projects to the server configuration.

Bug fixes

• Honour 'repository' setting in client configuration file.
• Make the server not die on reloading.
• Re-open server log properly on reload.
• Fix forced single-line commit mode.
• Documentation fixes, brushed-up packaging.

Coming up soon

• Short URL support!
• Broadcast channels that report commits from all repositories (like CIA did on #commits).
• New --fake option to kgb-client, to test configurations.
• Add --save option to kgb-add-project to save changes to the config file.
• Move URL shortening to bot (configurable).
• Ability to use client-driven color schemes. Can be used to disable all color.

Tags: Planet Debian, KGB

Release 0.2.6 of RProtoBuf arrived on CRAN earlier this morning. RProtoBuf provides GNU R bindings for the Google Protobuf data encoding library used and released by Google. This release was once more driven largely by Murray whom we have now added among the list of authors of the package too. The NEWS file entry follows below:

Changes in version 0.2.6 (2012-10-04)

• Applied several more patches by Murray to
  • correct '_' and '__' mismatches in wrapper calls
  • update a few manual pages for style, and add examples
  • fix a bug where NAs were silently treated as TRUE for logical/bool types
  • fix a bug that caused crashes when adding vectors to optional fields
  • fix bugs in readASCII that returned empty protocol buffers when the file or connection could not be opened
  • distinguish between non-existant and not-set fieldswith has() by returning NULL in the former case.
  • fix a bug that caused non-deterministic behavior when setting a repeated message field in a protobuf to a single Message.
  • add unit tests for all of the above.
• Added Murray to Authors: field in DESCRIPTION
• Removed old and unconvincing example on RProtoBuf for storage and serialization in an imagined HighFrequencyFinance context

CRANberries also provides a diff to the previous release 0.2.5. More information is at the RProtoBuf page which has a draft package vignette, a 'quick' overview vignette and a unit test summary vignette. Questions, comments etc should go to the rprotobuf mailing list off the RProtoBuf page at R-Forge.

I visited my local library at the weekend, on a whim. (The weekend before, I'd been to the British Library for the first time, so I guess this inspired me.) The computing sections at public libraries do not tend to inspire me, on the whole. Southampton's is actually relatively good - there are four tall bookcases assigned to computing, although one is introductory IT (Word and Excel), and another seems to be assigned to graphic design (Photoshop). Still, the two in the middle do have some programming texts - you just have to work around "Red Hat Linux 7 for Dummies" and the like. I think the trouble is, computing books become obsolete so quickly; you don't get point releases of Shakespeare every six months. I also suspect the low demand for serious computing texts creates a vicious circle, where the type of people who might want that sort of thing know better than to look in the library for it. It got me thinking - could this be changed? Could I change it?

Hello Planet Debian. This post serves as a confirmation that my feed/blog setup is working. I am a DD since a few months and will blog occasionally about my Debian activities.

Is Asperger Syndrome a Disability? Some people tell me that I m disabled. Usually it s an unstated implication such as referring to Asperger Syndrome as a disability with the assumption that I ll agree. One time I had someone assume that I had never had a paid job because they knew I m an Aspie, maybe I should boast more about my career successes. One interesting take on this is represented by Maco s bost about Disablism/Ablism where she says Vocab note: A person has an impairment. Society s treatment of that impairment is what disables the person [1]. The same concept is presented by BRAINHE in their Social Model of Disability document [2]. The Wikipedia page on Ableism says The ableist worldview holds that disability is an error, a mistake, or a failing, rather than a simple consequence of human diversity, akin to race, ethnicity, sexual orientation or gender [3]. This is fairly close to the position that Neurodiversity [4] advocates take on Autism. Jaarsma P and Welin S wrote an interesting paper titled Autism as a Natural Human Variation: Reflections on the Claims of the Neurodiversity Movement [5] which considers these issues in depth and comes to the conclusion that High Functioning Autism (for which Asperger Syndrome is generally regarded as a synonym) is a difference while Low Functioning Autism is a disability. I think that generally we should accept the opinion of the person in question. Someone who is unable to communicate or is too young to make an informed decision could have their disability status determined by carers. But anyone who is capable of making an informed decision and communicating it should have their opinion respected. I am not going to argue with any of the people who claim that they are disabled due to an Autism Spectrum Disorder. But I don t think that I am disabled and I think that people shouldn t argue with me about this. Over Pathologising Lynne Soraya wrote an interesting article for Psychology Today about one aspect of the supposed over-diagnosis [6]. She responds to Paul Steinberg, a psychiatrist who made a number of claims about Asperger Syndrome which lack evidence. Paul s main idea seems to be that anyone who has social problems but who seems to be successful regardless shouldn t have an Autism Spectrum diagnosis and he claims that such people should be regarded as having a social disability instead. His main idea seems to be that having a diagnosis is a bad thing, but his idea of having a social disability diagnosis instead doesn t seem so great. In many other discussions I ve seen people claim that a large number of diagnosis of anything is a problem. Their idea seems to be that the vast majority of the population shouldn t have a diagnosis for anything and that whenever a significant number of people are diagnosed with a psychological condition (and 1% of the population seems to be a significant number) then it s a problem. I don t think that having a large portion of the population diagnosed is necessarily a problem, I think that it would be OK if the majority of the population was diagnosed with something. The issue is not whether people are diagnosed but what happens after the diagnosis. When a child is diagnosed their parents can help them deal with whatever the issues are this may or may not require further involvement with psychologists or special schools. For the milder cases (of Autism, ADHD, and other conditions) merely knowing what areas will cause difficulty and teaching kids how to deal with them will be enough to solve many problems. When someone is diagnosed as a child but doesn t have obvious symptoms as an adult that is more likely to be an indication that they were taught good coping mechanisms and protected from bad situations as a child not that the diagnosis was wrong. There are some serious issues with special schools and psychiatric drugs, but diagnosis doesn t necessarily imply mistreatment and avoiding a diagnosis is not the correct way to avoid such mistreatment. When someone is diagnosed as an adult they have to learn to deal with it. The general lack of psychologists (waiting times as long as 6 months are common) and the fact that most psychologists won t do any good for someone on the Autism Spectrum is a real problem. But merely knowing the source of your problems is a major step towards alleviating or solving them. One of the arguments that is commonly used against so-called over-diagnosis is that adults don t show apparent symptoms. The issue here is that with some effort and planning adults on the spectrum can act like NTs. Acting like an NT doesn t imply being an NT, it usually requires a lot of ongoing effort that could be applied to other things if society didn t expect us to act like NTs all the time. Conclusion I wish people would stop telling me that I m either disabled or too high functioning to be on the Autism Spectrum. I will never think like an NT and I don t want to, so I ll always be an Aspie. By most objective measures I m at least as successful as the general population in all things that require social skills, so unless something like always losing at Poker is considered a disability I don t think that it s reasonable to consider me to be disabled. It would be nice if I could lock the people who claim that Autism is always a disability in a room with the people who think it s over-diagnosed and let them debate it, no matter which side lost the debate the result would be good! Update: I removed a broken link to a Youtube video, I published this post from a 3G connection and didn t test that the Youtube link still worked. For some reason the author had marked it private since the last time I visited it.

• [1] http://ubuntulinuxtipstricks.blogspot.com.au/2011/05/blogging-against-disablism-day-asl.html
• [2] http://www.brainhe.com/TheSocialModelofDisabilityText.html
• [3] http://en.wikipedia.org/wiki/Ableism
• [4] http://en.wikipedia.org/wiki/Neurodiversity
• [5] http://www.imh.liu.se/avd_halsa_samhalle/filarkiv1/1.264263/JaarsmaWelin2011Autismasanaturalvariation.pdf
• [6] http://www.psychologytoday.com/blog/aspergers-diary/201202/is-aspergers-overdiagnosed

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It appears that a recent incident at a different campus of the "preschool" (I call it day care) that Zoe goes to has gotten the attention of the Free-Range Kids blog. Firstly, I need to say that on the parenting spectrum, I definitely self-identify closer to the free-range end than the helicopter end. I'm not sure that I'd let an 8 year old ride the New York subway on their own, but Zoe's not 8 yet, so I really can't say. Sarah and I received the same email that is reprinted on the blog, on Friday night, and we were both (very) mildly alarmed at the situation, but not particularly concerned, mostly because it wasn't the facility that Zoe goes to. I'm not sure I'd be that much more concerned if it was, to be honest. I did like the statistics that the parent quoted in response. I thought that that put things into perspective, but didn't really take abductions by estranged parents into consideration. My one reaction to reading the email was, "why did they wait until after the incident to escalate it?" but then, from my own experiences in dropping off or picking up Zoe, I could totally understand not all the staff knowing on sight all the parents or guardians that do pickups and drop offs. This does lead to one asking how they know who to buzz in, but that's another can of worms. Anyway, I read the 50 or so varyingly indignant comments on the Free Range Kids blog, and since they were talking about the company that I give a not inconsequential amount of money to, I feel the need to write a response.

• it's a day care centre "chain". They have kids ranging from infant to pre-K (if I'm getting my grade terminology correct). It's not what I'd call a "school", hence they call themselves a "preschool"
• having actually been to one of the facilities, I can understand the request to not mingle in the lobby. It's tiny, and it blocks the view of the doors from the front office, where an employee is usually buzzing people in from
• I can totally understand the desire by the staff to not hold the door open for other people, even if we "know" them, because of possible changes in family circumstances. I would say that there's a difference between knowing someone by sight, because they're always dropping off or picking up their kid at the same time as you are, and knowing their name, where they live, etc. Having done pickups and drop offs, there are parents in both categories. I'll still hold the door open for a parent that we socialise with outside of "school", but I'll think twice now before doing it for someone who only looks familiar but I don't really know. I don't want to be the one who facilitates a future incident
• I think a lot of the conservative position the day care management has stems from liability. I have no problem with that. If the shoe was on the other foot, and an estranged parent had walked in and taken their child, and the centre had a "locked door" policy, there'd be some uncomfortable questions to answer. I'm paying them a boatload of money, they say they operate under a "locked door" policy, I expect them to keep my kid safe

The whole episode raises the question: who was this person and what were they doing there? Some of the commentators hypothesize that they were casing the joint for a future incident, or just giving themselves an impromptu tour before placing their child there (Zoe and I toured before we signed up, but that was an official, prearranged thing). It really is unfortunate that the staff didn't challenge this person, but as I said, they probably all had to review the video surveillance footage together to ascertain that none of them knew who the person was. I consider this a bit of a deficiency itself, but I don't really expect them to all have photographic memory, especially if one parent mostly does drop off and pick up. The other (expensive) option would be to issue each authorized person with an electronically revocable proximity card, so they can let themselves in, but I feel that that's taking things to the extreme. They staff all carry portable radios. If they don't have a discreet "code" they can call when one of them sees a person they don't know, I'm sure they will have after this incident. I personally found the majority of the comments on the Free Range Kids blog to be on the extreme overreaction side of things. As much as I'm a believer in Free Range parenting, I think the day care provider has mostly reacted appropriately. Do I agree with their "locked facility" policy? It's my first experience with a commercial day care facility, so I don't have anything to compare it with. As I said earlier, I can totally understand where they're coming from in terms of limiting their liability. Previously, Zoe was in a "home day care" facility, without any locks, and I for one wasn't constantly worrying about someone wandering into that provider's home and abducting my daughter, so I guess the whole "locked facility" thing is on the more extreme end of the scale for me in the first place, but like I said, I'm uncalibrated for commercial day care centres. I'd certainly like to see the primary school environment that Zoe goes to not be such a locked down affair.

I was working on writing tests for gnome-settings-daemon a week or so ago, and finally got blocked on being unable to set up upower/ConsoleKit/etc. the way I need them. Also, doing so needs root privileges, I don t want my test suite to actually suspend my machine, and using the real service is generally not suitable for test suites that are supposed to run during make check , in jhbuild, and the like these do not have the polkit privileges to do all that, and may not even have a system D-Bus running in the first place. So I wrote a little test_upower.py helper, then realized that I need another one for systemd/ConsoleKit (for the system idle property), also looked at the mock polkit in udisks and finally sat down for two days to generalize this and do this properly. The result is python-dbusmock, I just released the first tarball. With this you can easily create mock objects on D-Bus from any programming language with a D-Bus binding, or even from the shell. The mock objects look like the real API (or at least the parts that you actually need), but they do not actually do anything (or only some action that you specify yourself). You can configure their state, behaviour and responses as you like in your test, without making any assumptions about the real system status. When using a local system/session bus, you can do unit or integration testing without needing root privileges or disturbing a running system. The Python API offers some convenience functions like start_session_bus() and start_system_bus() for this, in a DBusTestCase class (subclass of the standard unittest.TestCase ). Surprisingly I found very little precedence here. There is a Perl module, but that s not particuarly helpful for test suites in C/Vala/Python. And there is Phil s excellent Bendy Bus, but this has a different goal: If you want to thoroughly test a particular D-BUS service, such as ensuring that it does the right thing, doesn t crash on bad input, etc., then Bendy Bus is for you (and python-dbusmock isn t). However, it is too much overhead and rather inconvenient if you want to test a client-side program and just need a few system services around it which you want to set up in different states for each test. You can use python-dbusmock with any programming language, as you can run the mocker as a normal program. The actual setup of the mock (adding objects, methods, properties, etc.) all happen via D-Bus methods on the org.freedesktop.DBus.Mock interface. You just don t have the convenience D-Bus launch API. The simplest possible example is to create a mock upower with a single Suspend() method, which you can set up like this from Python:

import dbus
import dbusmock
class TestMyProgram(dbusmock.DBusTestCase):
[...]
    def setUp(self):
        self.p_mock = self.spawn_server('org.freedesktop.UPower',
                                        '/org/freedesktop/UPower',
                                        'org.freedesktop.UPower',
                                        system_bus=True,
                                        stdout=subprocess.PIPE)
        # Get a proxy for the UPower object's Mock interface
        self.dbus_upower_mock = dbus.Interface(self.dbus_con.get_object(
            'org.freedesktop.UPower', '/org/freedesktop/UPower'),
            'org.freedesktop.DBus.Mock')
        self.dbus_upower_mock.AddMethod('', 'Suspend', '', '', '')
[...]
    def test_suspend_on_idle(self):
        # run your program in a way that should trigger one suspend call
        # now check the log that we got one Suspend() call
        self.assertRegex(self.p_mock.stdout.readline(), b'^[0-9.]+ Suspend$')

This doesn t depend on Python, you can just as well run the mocker like this:

python3 -m dbusmock org.freedesktop.UPower /org/freedesktop/UPower org.freedesktop.UPower

and then set up the mocks through D-Bus like

gdbus call --system -d org.freedesktop.UPower -o /org/freedesktop/UPower \
      -m org.freedesktop.DBus.Mock.AddMethod '' Suspend '' '' ''

If you use it with Python, you get access to the dbusmock.DBusTestCase class which provides some convenience functions to set up and tear down local private session and system buses. If you use it from another language, you have to call dbus-launch yourself. Please see the README for some more details, pointers to documentation and examples. Update: You can now install this via pip from PyPI or from the daily builds PPA. Update 2: Adjusted blog entry for version 0.0.3 API, to avoid spreading now false information too far.

SMS is used to lock car doors Copenhagen Carpool soon receive a new batch of electric cars. The new cars will contain a cellphone tied to the door locks, to only let into the car the member who booked its current timeslot. I am setting up the system to connect the cars with their booking calendar. The general idea is to

1. Connect a standard cellphone to a computer.
2. Forward sms messages received on the phone to the calendar.
3. Send messages from the calendar through the phone.
4. Leave the system in a corner, turned on 24/7.

Most of my work is in trying to avoid ways things might go wrong which so often happens when computers are involved. What if

• messages are delayed or lost?
• a chain of messages arrive out of order?
• messages are sent faster than they can be delivered?

Reliable conversation Human conversation is most reliable when using plain speak. Slang, sarcasm or jokes raise the risk of misunderstandings. This is quite similar in computer conversation. When surfing the Web, you normally "GET" a web page or "POST" new data like a search query. The words "GET" and "POST" are "plain speak" of the World Wide Web defined as a principle called "REST" or "RESTful design". I use the Kannel tool to talk directly to the phones. When an sms arrives on the phone, Kannel "GET"s it to the calendar. That's weakly expressed better if it had "POST"ed the message instead. Kannel is a quite reliable tool, but not RESTful in conversations. That requires extra attention at other parts of the setup to avoid breakage in special situations. That worries me.

Each car has a blog So I setup a gateway from Kannel to RESTful conversation. And choose classic blogging as style of conversation:

• The carpool fleet is a blogroll
• each car has a blog
• each sms emitted from a car is a blog entry

Blogging comes in two flavors, RSS and Atom. Both cover distribution of messages. I use Atom because it is newest and coolest, and because it also covers creating and editing meesages with the AtomPub extension. AtomPub allows the calendar to create an empty message which then triggers an sms from the car which "fills it in." AtomPub also let the calendar "PUT" tags onto existing messages, to mark them as processed, read etc., and let an admin or a cleanup script "DELETE" outdated entries or blogs. The words "PUT" and "DELETE" are RESTful conversation as well.

The system is dancing! My sms-to-blog gateway is written in Perl, using the Dancer toolkit. Dancer makes it simple to setup a RESTful web conversation, and when I contacted the authors on IRC, they swiftly added support for the non-RESTful quirk that I needed. My sms-to-blog gateway is not yet ready, but basic routines work. The project is public, and code is Free Software.

Scott Adams has an interesting idea for political debates he calls Fact Bubbler [1]. It sounds implausible the first time you read it, but then so did Wikipedia. Arstechnica has an interesting article on software defined radio [2]. This could change many things. The Nieder Family has another update on the way patents threaten their daughter s ability to communicate [3]. Also Apple is making things worse by taking pre-emptive strikes against iPhone apps which are involved in legal disputes never use an iPhone (or other proprietary system) for anything important if you have a choice. In more positive news crowd-funded gene sequencing has found an explanation for Maya Nieder s developmental delays [4]. This will revolutionise medicine! Steven Cherry of IEEE Spectrum has an interesting interview with Peter Cappelli about the difficulties that computer and engineering companies have in hiring talented people [5]. The Guardian has an interesting article about the non-profit investigative reporting organisation ProPublica [6]. See the ProPublica.org site for some quality news reports [7]. Michael O.Church wrote an interesting and insightful article about the fate of a Just a Programmer in a startup funded by Venture Capitalists [8]. It doesn t sound good at all. EyeNetra is developing a smart-phone based system for testing eyes [9]. It s apparently possible to manufacture glasses for $0.75 so the cost and difficulty of performing eye tests is the main factor that prevents poor people in developing countries from getting glasses. So a cheap portable eye testing system is going to help many people get the glasses they need. Bryan Gardiner wrote an interesting article for Wired about the Gorilla glass that is used in most mobile phones and tablets [10]. Maco wrote an interesting article about crochet and reverse-engineering along with a Python program to print a crochet pattern [11]. I wonder whether anyone has tried to make a crochet robot, something like a 3D printer but which crochet s things rather than printing them. Holding the wool would be a real challenge, it s not nearly as easy as printing on something that s stuck down and incapable of movement.

1. [1] http://dilbert.com/blog/entry/fact_bubbler/
2. [2] http://arstechnica.com/tech-policy/2012/07/how-software-defined-radio-could-revolutionize-wireless/
3. [3] http://niederfamily.blogspot.com.au/2012/06/silencing-of-maya.html
4. [4] http://blog.ted.com/2012/07/17/newly-discovered-gene-may-explain-4-year-olds-rare-disease-thanks-to-ted-fellow-jimmy-lin/
5. [5] http://spectrum.ieee.org/podcast/at-work/tech-careers/why-bad-jobsor-no-jobshappen-to-good-workers
6. [6] http://www.guardian.co.uk/technology/2012/jul/02/propublica-investigative-reporting
7. [7] http://www.propublica.org/
8. [8] http://michaelochurch.wordpress.com/2012/07/08/dont-waste-your-time-in-crappy-startup-jobs/
9. [9] http://eyenetra.com/
10. [10] http://www.wired.com/wiredscience/2012/09/ff-corning-gorilla-glass/all/
11. [11] http://ubuntulinuxtipstricks.blogspot.com.au/2010/10/algorithms-reverse-engineering-and.html

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My foray into the world of LXC and RLXC A few months ago, I started trying out LXC (Linux Containers). Before that I used to use OpenVZ, which is an older and more mature contextualization implementation. I was pleased with how well LXC worked and started replacing my personal OpenVZ hosts with LXC. It worked great, but it had a few quirks. While LXC itself works well, the user scripts that ship with it has some space for improvement. The lxc-list command lists anything that s a directory in /var/lib/lxc, so if you have a lost+found directory, it will list it as a container (This has since been fixed upstream). Also, in some cases it would list containers twice or not at all. I was a bit annoyed with that, since OpenVZ s vzlist tool prints out a nice table of your containers along with their IP addresses and other information. Since it s very trivial to implement what I want in a shell script, I went ahead and did just that and called it RLXC. I also missed the vzctl exec <containername> command to execute commands in containers and vzctl enter <containername> to gain a shell inside the container, so I added some more functionality to it so that I could configure ssh keys for these containers and use rlxc enter and rlxc exec like I used to do with the OpenVZ tools, but by using SSH. I also realised that there are others too who wanted similar improvements in the LXC scripts and decided to continue improving RLXC and making it public. Enter LLXC I spoke to St phane about my ideas at the time and he introduced me to python3-lxc that he introduced on his blog yesterday. It provides Python bindings for liblxc, so I took the advantage of that and mostly re-implemented RLXC in Python and called it LLXC. The name doesn t particularly mean anything, I m open to suggestions for what to call it, if anyone cares. Here are some screenshots that explains some of it better than I could do in words: How to get it As St phane mentioned in the python3-lxc blog entry, the API hasn t yet been finalized and llxc itself is in an early state and many changes are planned, so it s definitely not meant for production use yet, but since we believe in release early, release often in the free software community, here goes Currently, llxc.py itself is *very* Ubuntu specific and its only been tested on Ubuntu 12.04, but that will be fixed once more of its kinks have been ironed out. Some people are also working on getting python3-lxc on other distributions, which will help a lot. The llxc.py script itself is hosted on Github: https://github.com/highvoltage/llxc For python3-lxc and friends, you need to enable St phane s experimental PPA: https://launchpad.net/~stgraber/+archive/experimental You will then need to install the following packages: lxc, python3-lxc, python3-crypto, lvm, btrfs-tools To generate the ssh keys used for ssh interaction between the containers, you need to run llxc gensshkeys . The enter and exec commands also rely on your containers being in dns or in your /etc/hosts file, at least for now, which you may have to configure manually. The Future There is a lot that I m planning to add, mostly to scratch my own itches. These include:

• Awareness of other hosts, so that the list command can show you all containers in the awareness . You d also be able to clone, move, etc containers between hosts.
• Easily modify container configuration
• Hooks everywhere, and at least one hook for configuring a configuration management system such as salt, bcfg2, puppet or chef.
• More checks and tips everywhere. Is the host running low on memory? Disk space? Perhaps list available resources on variable hosts and make some suggestions based on that.
• There a not-very-descriptive ROADMAP file in the distribution, check that for more details.

I ll have some packaging for this available soon and work on making more things work right out of the box, updates will follow. Also, feedback and patches are very welcome!

Back at the beginning of September, Jo and I were invited up to Aberdeen for a weekend for a party to celebrate the 50th wedding anniversary of some friends. Then we decided to stay around for a few days - it was our 1st anniversary just two days later. :-) We had a great time at the party, and had some awesome weather for the weekend (especially considering the time of year!). We travelled around a bit for the next few days, visiting Crathes Castle, John O' Groats and Culloden amongst other places. We stayed in a hotel overlooking Loch Ness for the evening of our own anniversary, but no sign of Nessie! We headed back via Gretna Green and visited the famous (if tacky!) Blacksmith's there, then headed home. Having done both Land's End and John O' Groats in one year, we've covered the length of Great Britain. We thoroughly enjoyed ourselves for a few days, especially the lovely roads with very few people on them! Also we got to see some very unusual road signs that made us chuckle...

We'll definitely go back again soon!

A couple days ago, I woke up to this exciting series of text messages from a unfamiliar phone number. Because I've not received a reply in the last couple days, because it was a Seattle phone number but I haven't lived in Seattle for years, and because I don't know of anyone in Seattle who was about to give birth, I'm pretty confident that this was indeed a case of misdirected text messages! But whoever you are: Congratulations! I know it was a mistake, but that really made my day!

The only mail-filing feature that is consistently available across all mail clients (web, mobile, desktop) and most often via a convenient button, keypress or gesture, is Delete. For a long time, I've had an email work-flow that involved archiving most mail: saving both sent and received mails to a series of folders, so I could refer back to them if necessary (and they turned up in search results). Lots of mail clients make this easy: Thunderbird supports defining an Archive folder and pressing 'a' when a mail is highlighted will move it into Archive/YYYY. Mutt, of course, can be configured to do almost anything, and I've had it set up to move mail into =archive when you hit 'a' for a long time. Sadly, other clients are not as friendly. Outlook doesn't support anything quite so convenient. Mobile clients on Android, iPhone etc. don't have easy archiving support. Neither do webmail clients like OWA. Increasingly, I check my work mail on the go: waiting for a lift, on the train to work, in a irrelevant part of a meeting, waiting for a coffee refill, etc. However, I can rarely file mail this way: I learn facts, I can react to things quickly, but I can't keep my inbox under control. For this reason I'm adjusting my workflow around 'Delete'. For work, I've set up an Exchange filter to automatically copy any message that lands in my Inbox into an Archive folder. This was surprisingly difficult to get right, and there are ongoing problems with conversation view and other things. However, once that is in place, I can merrily delete stuff from my Inbox with impunity, safe in the knowledge that I can still get stuff via search if needed. I'll need a separate process to further organise filtered mail, but that's fine. Launching mutt or Thunderbird specifically to shuffle mail into e.g. archive/2012 works for me. I still need to run my mail archiving script to extract attachments on occasion anyway.

I ve just read Diego s response to an ill-informed NYT article about data-center power efficiency [1]. This makes me wonder, how much server use does each person have? Google Almost everyone uses Google, most of us use it a lot. The main Google product is also probably the most demanding, their search engine. In a typical day I probably do about 50 to 100 Google searches, that sounds like a lot, but half of them would probably be for one topic that is difficult to find. I don t think that I do that many Google searches because I generally know what I m doing and when I find what I need I spend a lot of time reading it. I m sure that many people do a lot more. Each Google search takes a few seconds to complete (or maybe more if it s an image search and I m on a slow link), but I think it s safe to assume that more than a few seconds of CPU time are involved. How much work would each Google search take if performed on a single system? Presumably Google uses the RAM of many systems as cache which gives a result more similar to a NUMA system than one regular server working for a longer time so there is no way of asking how long it would take to do a Google search with a single server. But I m sure that Google has some ratio of servers to the rate of requests coming in, it s almost certainly a great secret, but we can make some guesses. If the main Google user base comprises people who collectively do an average of 100 searches per day then we can probably guess at the amount of server use required for each search based on the number of servers Google would run. I think it s safe to assume that Google doesn t plan to buy one server for every person on the planet and that they want to have users significantly outnumbering servers. So even for core users they should be aiming to have each user only take a fraction of the resources that one server adds to the pool. So 100 searches probably each take more than 1 second of server use. But they almost certainly take a lot less than 864 seconds (the server use if Google had one server for every 100 daily requests which would imply one server for each of the heavier users). Maybe it takes 10 seconds of server use (CPU, disk, or network whichever is the bottleneck) to complete one search request. That would mean that if the Google network was at 50% utilisation on average then they would have 86400*.5/10/100 == 43 users per server for the core user base who average 100 daily requests. If there are 80M core users that would be about 2M servers, and then maybe something like another 4M servers for the rest of the world. So I could be using 1000 seconds of server time per day on Google searches. I also have a Gmail account which probably uses a few seconds for storing email and giving it to Fetchmail, and I have a bunch of Android devices which use Google calendars, play store, etc. The total Google server use on my behalf for everything other than search is probably a rounding error. But I could be out by an order of magnitude, if it only took 1 second of server use for a Google search then I would be at 100 server seconds per day and Google would only need one server for every 430 users like me. Google also serves lots of adverts on web sites that I visit, I presume that serving the adverts doesn t take much resources by Google standards. But accounting for it, paying the people who host content, and detecting fraud probably takes some significant resources. Other Big Services There are many people who spend hours per day using services such as Facebook. No matter how I try to estimate the server requirements it s probably going to be fairly wrong. But I ll make a guess at a minute of server time per hour. So someone who averages 3 hours of social networking per day (which probably isn t that uncommon) would be using 180 seconds of server time. Personal Servers The server that hosts my blog is reasonably powerful and has two other people as core users. So that could count as 33% of a fairly powerful server in my name. But if we are counting server use per USER then most of the resources of my blog server would be divided among the readers. My blog has about 10,000 people casually reading it through Planet syndication, that could mean that each person who casually reads my blog has 1/30,000 of a server allocated to them for that. Another way of considering it is that 10% of a server (8640 seconds) is covered by me maintaining my blog and writing posts, 20% is for users who visit my blog directly, and 3% is for the users who just see a Planet feed. That would mean that a Planet reader gets 1/330,000 of a server (250ms per day) and someone who reads directly gets 1/50,000 of a server (1.72s per day) as I have about 10,000 people visiting my blog directly in a month. My mail server which is also shared by a dozen or so people (maybe that counts as 5% of a server for me or 4320 seconds per day). Then there s the server I use for SE Linux development (including my Play Machine) and a server I use as a DNS secondary and a shell server for various testing and proxying. Other People s Servers If every reader of a Planet instance like Planet Debian and Planet Linux Australia counts as 1/330,000 of a server for their usage of my blog, then how would that count for my own use of blogs? I tend to read blogs written by the type of people who like to run things themselves, so there would be a lot of fairly under-utilised servers that run blogs. Through Planet Debian and Planet Linux Australia I could be reading 100 or more blogs which are run in the same manner as mine, and in a typical day I probably directly visit a dozen blogs that are run in such a manner. This could give me 50 seconds of server time for blog reading. Home Servers I have a file server at home which is also a desktop system for my wife. In terms of buying and running systems that doesn t count as an extra server as she needs to have a desktop system anyway and using bigger disks doesn t make much difference to the power use (7W is the difference between a RAID-1 server and a single disk desktop system). I also have a PC running as an Internet gateway and firewall. Running servers at home isn t making that much of an impact on my computer power use as there is only one dedicated 24*7 server and that is reasonably low power. But having two desktop systems on 24*7 is a significant factor. Where Power is Used/Wasted No matter how things are counted or what numbers we make up it seems clear that having a desktop system running 24*7 is the biggest use of power that will be assigned to one person. Making PCs more energy efficient through better hardware design and better OS support for suspending would be the best way of saving energy. Nothing that can be done at the server side can compare. Running a server that is only really used by three people is a significant waste by the standards of the NYT article. Of course the thing is that Hetzner is really cheap (and I m not contributing any money) so there isn t a great incentive to be more efficient in this regard. Even if I allocate some portion of the server use to blog readers then there s still a significant portion that has to be assigned to me for my choice to not use a managed service. Running a mail server for a small number of users and running a DNS server and a SE Linux development server are all ways of wasting more power. But the vast majority of the population don t have the skills to run their own server directly, so this sort of use doesn t affect the average power use for the population. Nothing else really matters. No matter what Google does in terms of power use it just doesn t matter when compared to all the desktop systems running 24*7. Small companies may be less efficient, but that will be due to issues of how to share servers among more people and the fact that below a certain limit you can t save money by using less resources particularly if you pay people to develop software. Conclusion I blame Intel for most of the power waste. Android phones and tablets can do some amazing things, which is hardly surprising as by almost every measure they are more powerful than the desktop systems we were all using 10 years ago and by many measures they beat desktop systems from 5 years ago. The same technology should be available in affordable desktop systems. I d like to have a desktop system running Debian based on a multi-core ARM CPU that can drive a monitor at better than FullHD resolution and which uses so little power that it is passively cooled almost all the time. A 64bit ARM system with 8G of RAM a GPU that can decode video (with full Linux driver support) and a fast SSD should compete well enough with typical desktop systems on performance while being quiet, reliable, and energy efficient. Finally please note that most of this post relies on just making stuff up. I don t think that this is wrong given the NYT article that started this. I also think that my estimates are good enough to draw some sensible conclusions.

• [1] http://blog.diegodoval.com/2012/09/23/a-lot-of-lead-bullets-a-response-to-the-new-york-times-article-on-data-center-efficiency/

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in this series of articles, I will be talking in depth about power management through the NUT project, its packaging on Debian, how to use it in general and how I see it being part of the GreenIT thing. So, let's start with an introduction: NUT is a Free Software (GPL v2+ and 3 to be precise), originally created for power protection using UPS, from home to data-centers:
To shortly describe the main features, I would say that NUT:

• has the most comprehensive list of supported devices: 127 manufacturers and thousands of devices,
• is modular and flexible, to address all possible use cases,
• weight a few hundreds Kb,
• runs on any system, is packaged for the major ones, and is bundled with most (if not all) Linux,
• provides tons of features,
• is network oriented: you can access uniquely devices all around the world, in a secured way,
• is optimized for integration and interfacing,
• is supported by many 3rd party software,
• is already embedded in several devices, found in home, enterprises and datacenters.

NUT used to stand for Network UPS Tools. That is, a software for talking to your UPS and shutting down your systems when needed. This definition is a bit limited nowadays, since NUT supports 4 types of power device:

• UPS, obviously, since the origin.
• PDU (power distribution units), for 4 years. These are somehow big intelligent power switches, that you find in datacenters. These allow to switch on and off specific outlets and / or to measure power consumptions. The latter is more interesting for Green IT and PUE calculation. But this is the topic of another article
• SCD (solar controller device), for more than 2 years. NUT only supports 1 SCD (IVT SCD series), but support for another can be very easily added.
• PSU (power supply unit), for more than a year. This support is limited to server PSU, that are IPMI compatible.
• meters and gensets are also new device types that are considered. Meters would provide more measurement capabilities, still mainly for PUE calculation, while gensets.

Considering this, is the name Network UPS Tools still suitable? Not really! But the acronym NUT is well known! So, for the time being, I just stick using it, and focus on other more important things, until a better opportunity (ideas and comments are welcome!). That said, what can you do exactly with NUT? Currently, you can:

• monitor and manage UPS(s) that protect(s) your system(s), with no redundancy limitation,
• manage your PDU, to power on / off your systems (not servers directly!), and measure power consumptions,
• monitor and manage your servers power supplies, power these on / off, and measure power consumption.
• monitor all these links of the powerchain, that feed your servers.
• discover all USB, SNMP and IPMI supported devices, locally or on the network.

All the above is available in a standardized way:

• the manufacturer name will always be in the variable called device.mfr. The first outlet will always be outlet.1, whatever the device is (UPS or PDU here),
• Tons of command line tools, libraries / language bindings and software are available to help in NUT integration! You can even make your own NUT client implementation very easily and quickly (experiences reports are ~ 2 hours).

Well, this is already a long and dense post, so I will stop there for today. In the next post, we will have a deeper dive into using NUT, for various use cases: submit yours if you can cheers,
-- Arno

Hello Planet Debian. This post serves as a confirmation that my feed/blog setup is working. I am a DD since a few months and will blog occasionally about my Debian activities.

An interesting question popped up in my Twitter stream today is there an Android alternative to Apple configurator (for iPhone, iPad and iPod Touch) that allows to create a bunch of identical Apple devices with some added configurations and applications. The best I could come up with is not as polished, but on the other hand much more powerful option Nandroid backup and restore (also known as ClockworkMod Recovery backup). To do this, you need a source phone and a bunch of destination phones. On the source phone a ClockworkMod Recovery (CWR) must be installed (either via a root or via a bootloader unlock). On the destination phones you will either need to also install ClockworkMod Recovery or unlock the bootloader to allow the Fastboot tool to work. So the procedure then goes as follows:
1. Unlock the bootloader on the source phone (search for device specific info on how to do that)
2. Use fastboot flash recovery filename.img to write a device-specific version of CWR to the recovery partition of the device (the phone must be in fastboot mode at that point)
3. Do whatever customisations you want to the source phone at this point. You can use custorm ROMs, install whatever applications, do whatever configuration, but I would suggest keeping everything in phone memory so you don t have to flash the SD card as well.
4. Reboot the source phone into CWR mode, use the backup option to create a full backup.
5. The backup will now be in the SD card of the source device. Copy that to the computer that you will use for creating copies. For each destination phone:
6. Unlock the bootloader of the destination phone
7. Reboot the phone in the fastboot mode, connect it via USB to the copying computer
8. Flash all partitions from the backup using fastboot flash ... commands, skip flashing the recovery partition if you don t want CMR on the destination device
9. Re-lock the bootloader (with fastboot oem lock) And you are done! All the phones must be of the same model. And that model must support unlocking bootloader for this to work. I prefer this method, because this way it is possible to create an end device without root, with a locked bootloader and without CWR thus providing some security as unlocking the bootloader wipes the device, so without specific hacking an attacker can not easily get access to system data on such device. It is also possible to do this with devices that do not have an boot unlock if there is a way to root the original firmware which allows to install CWR and go on from there, but that is significantly more complicated and time-consuming, so using devices with an ability to unlock the bootloader is much preferable. However, before you go to all that trouble, it might be worth to consider if maybe for your particular use case it would be enough with the two commands from Android SDK adb install ... and adb push ... to install applications or individual files on devices or adb backup AppName and adb restore ... to backup and restore one or more individual applications with all their settings. These options have the benefit of that they will work across different device models and that they do not wipe other data or applications from the devices. As I could not immediately find a better way or even a detailed guide how to do this, I decided to write this post, so it would be easier for other people to find this information. If you know a better way, please do mention it in the comments section!