Erdogan and his nocturnal ovine pleasuring habits

Like many others who support free speech, I was very disappointed in yesterday's decision by a Hamburg court that it stands by its ban of a satirical poem by German comedian Jan Böhmermann. Herr Böhmermann, not a big fan of the Turkish president Recep Tayyip Erodgan and his oppression of both people and speech, narrated this poem "Schmägedicht" ("Defamation Poem") on his show on 31st March 2016.

Here's the original reading: if you have any German speakers in the room with you then now would be an excellent time to send them out.

Jan Böhmermann - Erdogan Gedicht (Jan Boehmermann Erdogan poem) (English subtitled) from mjchris on Vimeo.

As a public service, here is my transcription of the original text, plus a translation.

Sackdoof, feige und verklemmt Stupid as fuck, cowardly and uptight
Ist Erdogan, der Präsident is Erdogan, the president.
Sein Gelöt stinkt schlimm nach Döner His erection reeks of Doner kebab;
selbst ein Schweinefurz riecht schöner Even a pig fart smells better.
Er ist der Mann, der Mädchen schlägt He's a man who hits girls
und dabei Gummimasken trägt while wearing rubber masks.
Am liebsten mag er Ziegen ficken He loves most to fuck goats
und Minderheiten unterdrücken and repress minorities.
Kurden treten, Christen hauen Kicking Kurds, beating Christians
und dabei Kinderpornos schauen while gazing at kiddie porn.
Und selbst abends heisst’s statt schlafen And at night, instead of sleep,
Fellatio mit hundert Schafen Performs fellatio on a hundred sheep.
Ja, Erdogan ist voll and ganz Yes, Erdogan truly is
ein Präsident mit kleinem Schwanz A president with a small dick.
Jeden Türken hört man flöten Every Turk will tell you
die dumme Sau hat Schrumpelklöten the stupid pig has wrinkled balls.
Von Ankara bis Istanbul From Ankara to Istanbul
weiss jeder, dieser Mann ist schwul everyone knows this man's a poof,
pervers, verlaust und zoophil perverse, lice-ridden, an animal fucker.
Recep “Fritzl Priklopil” Recep (Josef) Fritzl (Wolfgang) Priklopil [the famous perverts]
Sein Kopf so leer wie seine Eier His head as empty as his balls,
der Star auf jeder Gangbang-Feier the star of every gangbang party.
Bis der Schwanz beim Pinkeln brennt Until his cock burns when he pisses
das is Recep Erdogan, der türkische Präsident That’s Recep Erdogan, the Turkish president.

The court assessment was that only 6 of the 24 lines were acceptable: you can view their transcript with "unacceptable" lines marked in red. Interestingly they didn't seem to object to the suggestion that Erdogan likes wearing rubber masks while beating girls.

Germany and Turkey, of course, have the right to make whatever laws they desire about the limits on free speech and criticism of women-beating dictators. We in turn have the right to tell them what we think of their laws, and of Recep Tayyip Erdogan - and in the future, whenever we see President Erdogan on screen, hear in our minds the bleating of a hundred happy sheep.

28 hours of racial lies

One of the latest bits of social justice posturing is the play "Every 28 hours", a project produced by the Oregon Shakespeare Festival:

Every 28 Hours is a national partnership focused on the widely shared and contested statistic that every twenty-eight hours a black person is killed by vigilante, security guard, or the police in the United States.
Regular readers will know that a maths-based arse-kicking is coming. But perhaps, disregarding the numbers, this play is still a compelling work? After all, Harold Pinter was a complete arse, but his plays could still pull in the crowds. Might it be the same here?
The Every 28 Hours Plays consist of 72 one-minute plays inspired by the Black Lives Matter movement, with participation from artists across the nation.
OK, maybe I'll save myself the price of the ticket and just gently gouge out my eyes with a spoon.

One black person killed every 28 hours is 312 black people murdered a year. This is 312 murders too many, no matter who's doing it - and, let's be clear, I'm not quibbling with this . However, let's put this in some numerical context, shall we? I'm assuming that the "Every 28 Hours" authors are mostly liberal arts majors, so I promise to go slow and show my working. (Which, I'd guess, is a sight more than they do.)

The Facts

I'm using the FBI 2015 crime figures, specifically Expanded Homicide Data Table 6 (Race, Ethnicity, and Sex of Victim by Race, Ethnicity, and Sex of Offender, 2015).

Race/Ethnicity of victim Total Race of offender
White Black / African-American Other Unknown
White 3,167 2,574 500 49 44
Black / African-American 2,664 229 2,380 13 42
Other race 222 60 34 126 2
Unknown race 84 34 20 6 24

The other key stat is that, as of 2010, 12.6% of Americans are black or African-American - 1 citizen in 8. I'm making a leap of faith that this fraction has not changed significantly in the past 6 years. Since white people are about 63% of the population, they outnumber black Americans 5 to 1.

The Math(s)

The obvious stat that leaps out - though is hard to state grammatically: white people kill approximately as many white people as black people kill black people. White-on-black and black-on-white killings are actually relatively infrequent. This is also true for the "other" racial category (Asian, mixed-race, Native America etc) which turns out to be a similar fraction of the US population as black / African-American, but only about 7% of the number of racial colleagues killed even if you incorporate the "unknown" category.

So we could produce a companion play "Every 220 Minutes" representing the time interval between one black person killing another black person. We could also write "Every 17 1/2 hours" for a black person killing a white person, and "Every 38 hours" for a white person killing a black person.

But wait! If we have to wait 38 hours for a white person to kill a black person, and a black person is killed by a vigilante / security guard / police officer every 28 hours, doesn't that mean that some of those vigilantes / security guards / police officers must be black (or other ethnic minority)? Why yes, it does. I wonder if "Every 28 Hours" brings out this aspect of the statistics.

The truly terrifying stat is simply that black Americans kill about the same number of people as white Americans despite being outnumbered 5:1. The fear of young black American males held by many white people is visceral rather than statistical - the rate at which black people kill white people is about what you'd expect given the relative proportion of population - but black people in the 20-29 age range should be fucking terrified of black males aged 17 to 24 because they are the ones doing most of the killing of victims in that age range.

Why in the name of all that is holy are the "Every 28 Hours" folks talking about (white) police officers as a deadly influence, when young black men do 10 times more killing?

The Weasels

Let's go back to the Every 28 Hours claim:

...every twenty-eight hours a black person is killed by vigilante, security guard, or the police in the United States [my italics]
Now why, do you think, they added those two extra categories? If they could say:
...every twenty-eight hours a black person is killed by the police in the United States
then wouldn't that be a more powerful message? Perhaps they're not using it because it's not true. The Washington Post reports 258 black people killed by police in 2015. If "Every 28 Hours" used that figure as its basis, it would be called "Every 34 Hours" instead.

The statutory ad hominem

"Every 28 Hours" producer Claudia Alick is big on artistic direction, with a minor in hip-hop coaching, but it seems that her MA from NYU and BA from GWU have not equipped her with the ability to do math. Or perhaps she has the ability, but also gained the power to ignore the figures for the greater good of spreading propaganda. She certainly doesn't seem to be concerned with actually improving the lives of, and reducing the horrific body count in, the black American community in any meaningful way.


The perils of parenting a pseudo-pocket pig

There are times when I wonder why I still bother to read the Guardian, given what it does to my blood pressure; and then there are articles which make it all worth while. This tale of porcine deception is one of the latter.

I can't possibly do Mr. Jenkins' article justice, you should certainly Read The Whole Thing, but a few things stand out. First, Mr. Jenkins plays to any number of stereotypes as a gentleman who likes other gentlemen: pets as substitute for children (check), strong propensity for public exposure(check), leveraging any excuse to promote his domestic arrangements (check). Second, he should have been a little less trusting of an "old school friend" who wanted to get a petite porker off her hands

We trained her like a puppy and took her to the vet after about a month. He took one look at her cropped tail and said, "I think you have a problem on your hands."
It turns out that a small pig is not the same as a miniature pig. A valuable lesson for Mr. Jenkins, and apparently also life-changing:
If you look a pig closely in the eyes, it’s startling; there's something so inexplicably human. When you’re lying next to her and talking, you know she understands. It was emotional realising she was a commercial pig. The more we discovered about what her life could have been, it seemed crazy to us that we ate animals, so we stopped.
Don't be fooled, Steve: if that pig had the chance, she'd eat you and everyone you love. Ask Brick Top Polford:


UC Berkeley is a focus for repression of free speech

Last night, the famed right-wing polemicist Milo Yiannopoulos was intending to speak at the University of California at Berkeley. It turns out that there are some people who would prefer that Milo not speak. Rioting, toppling light poles, beating up and pepper-spraying Milo/Trump supporters

It's a sad statement of today's political environment that I was nearly astounded to see UCB's Chancellor actually defending a decision not to cancel Milo's visit. After a rash of spineless cancellations of speaking invitations for Milo - and also for Ben Shapiro, who is much less provocative than Milo but still apparently prone to trigger mouth-frothing by university faculty - it's nice to see a university chancellor sticking up for the principle of free speech. The "right not to be offended" is a particularly pernicious concept and it was refreshing for it to be given short shrift.

Of course, the "anti-fascist" movement was not keen to let a Milo event pass unremarked, and duly turned up to riot. The violence caused the university to cancel the event, thereby providing a perfect example of the "heckler's veto". If you don't like someone's speech, just protest violently and their event will be cancelled. I can't see any problems arising from the incentives this has provided at all, no...

There was only one arrest as a result of the rioting. This is what worries me the most - that rioters not only get the effect they deserve, but can perpetrate their violence practically free of consequence. There's only one direction for future violence as a result, and it's not "down".



Nice speech, Theresa. A solid kicking of the NATO under-spenders, emphasis of shared ideals and values with the USA, doubling down on Brexit. Careful warnings about excessive isolationism, hinting at reservations with the ideas behind today's Muslim visa ban. Repeated callbacks to Ronnie and Maggie; will Donald and Theresa be the new power couple?

It seemed to go down very well with the Republican audience. I'm guessing that Polly Toynbee will hate it. [I also suspect that Theresa doesn't give a shit what Polly thinks.]


Entrumpment FTW

Your humble correspondent finds it hard to explain the feelings arising from the inauguration of the 45th President of the United States, one Donald J. Trump. This "Entrumpment" has acted like a lens focusing the most demented of opinions and acts, and truly it has been the most wondrous of spectacles. Watching the collective losing of excreta of the liberal media today has been non-stop entertainment.

In the Bay Area, much attention was focused yesterday on a proposed attempt to complete a human chain across the Golden Gate bridge. The target date was today and it didn't work out quite as well as the organisers might have liked:

Even though the actual hand holding only lasted for one minute, folks who took part in the human chain say the memory will last a lifetime. Bridge officials say there were some gaps across the span on the northern side, so couldn't give the group credit for the first successful human chain, but for participants, it didn't matter, history was still made.
So even on the most Democrat-Republican polarising day for many years, and in the most Democrat-friendly city of the most Democrat-friendly state, they couldn't get 3000 people organised to form a human bridge. It's almost as if the Trump opposition doesn't have the practical conviction of their opinions.


Scentrics finds that security is hard

Two years ago I wrote about Scentrics and their "Key Man" security proposal. I wondered idly what had happened there so did some Googling. Turns out that I'm the top two hits for [scentrics key man] which is heart-warming for me but suggests that their world-beating security patent might have sunk like a stone...

I went to their website www.scentrics.com and noted that it didn't redirect to https. I tried https://www.scentrics.com and lo! Chrome's Red "Not secure" Warning of Death appears. Seems that Scentrics can't even secure their website, which is not a little ironic when their home page trumpets "Secure with Scentrics".

All the pages on the site - even "Overview and Vision" and "Careers" - are hidden behind a sign-on box, declaring the website "invitation only" and inviting you to contact "admin@scentrics.com" if you'd like access. You can view headers, but that's about it. You wonder why they would be so sensitive about exposing information like that.

The 2016 news included a nugget from the Daily Telegraph in June:

Scentrics is poised to seek new funding that would value the company at more than $1 billion as it prepares to rollout its infrastructure for the first time.
"Poised", huh? I like that. I read that as "not yet ready". I also like the uncritical write-up of the company's pitch:
Individual messages and documents sent over the internet can be unlocked without compromising the overall security of the network, according to Scentrics's pitch to operators and governments.
Remember that this essentially involved encrypting one copy of a message with the recipient's public key, and another with a government/agency public key, and storing the latter to give the agency access on demand. The government and security agencies involved might not think that this "compromises" the overall security of the network, but as a consumer of the network's function I can assure them that I'd feel very differently. And of course for this to be effective all network users would have to use a very small ecosystem of only approved apps / browsers which implemented this dual encryption, and maintained the central repository of government-friendly encrypted messages. I'm sure there's no risk of systematic system compromise there by insiders at all.

Companies House shows three officers plus a secretarial company including our old friend Guruparan "Paran" Chandrasekaran. Looks like Sir Francis Mackay, David Rapoport and Dr. Thaksin Shinawatra resigned since 2014, which is interesting because the latter gent used to be the Prime Minister of Thailand, and Scentrics trumpted his role in the Telegraph piece, but as of 1 month ago he's out of his company role.

According to their June 2015 accounts they have about GBP4.2M in net assets, looks like they had an infusion of about GBP4.5M during the year. Going from this to a $1bn valuation seems... optimistic.

Update: Looks like Scentrics are diving into Singapore with advertisements for Project Manager and Devops roles there. This seems to be part of the Singapore government's "Smart Nation" project for a unified network in Singapore:

  • A Smart Nation is one where people are empowered by technology to lead meaningful and fulfilled lives.
  • A Smart Nation harnesses the power of networks, data and info-comm technologies to improve living, create economic opportunity and build a closer community.
  • A Smart Nation is built not by Government, but by all of us - citizens, companies, agencies. This website chronicles some of our endeavours and future directions.
Cutting through the marketing speak, Singaporeans will be using a government-provided network for all services including personal and business communication. With Scentrics playing a role, the benevolent semi-dictatorship of Singapore will be able to snoop on all its citizens' internal communications at will.

Scentrics seems to be very comfortable enabling a government's surveillance on its citizens. I wonder how this is going to work out for them long-term given the distinctly libertarian tilt of most software engineers.

[Disclaimer: no share position in Scentrics. Financially I don't care if they live or die. Personally, I'd incline towards the latter.]

Don't blame the tech industry for its "lack of diversity"

Tekla S. Perry, who's experienced enough in the technology world to know better, wrote a provocative piece in IEEE Spectrum this week titled "Why Isn't the Tech Industry Doing Better on Diversity? It's Google's and Facebook's Fault". This sprang from a discussion at "Inclusion In Silicon Valley" where Leslie Miley, Slack's director of engineering, excoriated Bay Area tech companies for their alleged lack of inclusion:

You come to Silicon Valley and you don't see people that look like me in positions of power [Miley is black]. If that's not hostile, what is?
You don't see Chinese Americans or Indian Americans in positions of power in the Federal government, despite 8 years of a black president. If that's not hostile to Chinese and Indian Americans, what is?

Leslie Miley is a mendacious asshole. There are many legitimate points to make about the disproportionately small number of black software engineers, and the horrendous educational and societal failings behind that - and let's be clear, prejudice against academically successful black engineers is a real thing from both the black and white communities - but Leslie's point is not one of those. He is jumping from "X is not happening" (observation) to "X must be being blocked by Y" (assumption). You'd think that a competent engineer would be better acquainted with logical reasoning. But looking at Miley's LinkedIn profile he's only spent a series of 2-3 year stints at a list of major tech companies (Google, Apple, Twitter) in engineering management roles; since you spend 3-6 months coming up to speed with a job like that, and assume you draw down effort in the 3 months looking for a replacement job before you leave, his actual engineering experience doesn't seem that great, and you wonder why he kept leaving each firm before his stock options started to vest in quantity... (This is of course the "play the man, not the ball" approach to argument, which is intellectually facile but no less well founded that Miley's approach to argument.)

I've said this before but let's say it again. The main reason that people of Afro-Caribbean descent are under-represented in the software engineering industry is because the dominant education requirement for that industry is a bachelor's degree in a numerical subject (STEM), and such people are correspondingly under-represented in that qualification bucket. Such under-representation is a major issue that needs fixing, but it's happening way before the Silicon Valley and other engineering companies get involved. There's a secondary issue that engineering companies in general should get better at finding bright numerate non-STEM-degree holders who will do well in software engineering with a small investment of training, but that's another blog post entirely - and in any case, Silicon Valley big firms do spend time and money looking in that general area.

It's not just Miley who's making dumb remarks at this diversity love-fest, of course:

The lack of diversity stems from hidden and systemic bias, believes Monique Woodard, a partner in 500 startups. "If you turned off the imported talent, would you look to Oakland and Atlanta? I'm not sure people would," she said.
This is bollocks on stilts, but not just for the reasons you think. Oakland is stuffed full of Bay Area tech workers, especially junior engineers. They live there because it is relatively cheap compared to San Francisco, Palo Alto, San Jose, Milpitas etc. Tech companies recruit people from Oakland all the gosh-darn time. What Monique Woodard means is that she doesn't believe that tech companies will go looking for the black talent in Oakland and Atlanta. Why isn't she saying this explicitly? You be the judge.

"Changing the practices that perpetuate the overwhelmingly white and male character of the Silicon Valley workforce are not going to be easy"
Male: yep. White: nope. In Silicon Valley, Caucasians are actually under-represented per the general population; Chinese and Indians are significantly overrepresented. In my experience, people who openly identify as gay or transgender are also markedly over-represented. By many reasonable measures, Silicon Valley is one of the most diverse environments there is - there is a huge population of people whose national original is not the USA, and they aren't just Indians and Chinese: there are substantial Russian, Korean, Polish, Filipino, Vietnamese and other nationalities.

What Ms. Woodard is actually saying is: "there aren't enough engineers with dark skin - excluding Indians - in Silicon Valley." Well, Ms. Woodard, why is that? Is there a peculiar conspiracy in hiring where the recruiters and hiring deciders are wide open to all sorts of people except those who are of Afro-Caribbean extraction? Is that what you are saying, or is it such a ridiculous notion that you have to resort to camouflaging it behind the umbrella of "diversity"?

Behind Miley's comments, at least, there's a nugget of good sense. The competition for engineers in Silicon Valley and its environs, and to some extent other places like Seattle (Microsoft/Amazon) and New York (Big Finance) is intense. If big firms want to find a cheaper source of good engineers then they should look at other major cities, such as Atlanta, Dallas, Austin. This is something of a risk though: you need to start a new engineering office, which means recruiting many tens of new engineers in addition to migrating some of your existing senior engineers down there to help build and train the teams, reinforce company culture and keep strong communication with the root offices. Up until now, this has been more of a risk than just upping the game in recruiting from the Bay: I suspect soon the numbers will cross a threshold that makes new engineering offices sufficiently financially attractive to be worth a try.

Bringing in new engineers from Republican states such as Texas and Georgia is also excellent for increasing diversity in the heavily Democratic (and worse, Californian) engineering cohorts of Silicon Valley. Yet, why is it that I suspect that Miley, Woodard et al don't regard that kind of diversity as desirable?


neveragain.tech virtue signalling

In the past couple of days I've seen all manner of prompts to add my name to the petition at neveragain.tech, solemnly swearing to:

  1. refuse to participate in the creation of databases of identifying information for the United States government to target individuals based on race, religion, or national origin.
  2. advocate within our organizations:
    • to minimize the collection and retention of data that would facilitate ethnic or religious targeting.
    • to scale back existing datasets with unnecessary racial, ethnic, and national origin data.
    • to responsibly destroy high-risk datasets and backups.
    • to implement security and privacy best practices, in particular, for end-to-end encryption to be the default wherever possible. to demand appropriate legal process should the government request that we turn over user data collected by our organization, even in small amounts.
  3. if I discover misuse of data that I consider illegal or unethical in my organizations:
    • I will work with our colleagues and leaders to correct it.
    • If we cannot stop these practices, we will exercise our rights and responsibilities to speak out publicly and engage in responsible whistleblowing without endangering users.
    • If we have the authority to do so, we will use all available legal defenses to stop these practices.
    • If we do not have such authority, and our organizations force us to engage in such misuse, we will resign from our positions rather than comply.
  4. raise awareness and ask critical questions about the responsible and fair use of data and algorithms beyond my organization and our industry.

The more perceptive readers will be surprised at how closely this declaration follows the election of Donald Trump as President of the USA, and wonder why - following the past 8 years of progressive weaponization of the Federal government - the tech industry has suddenly decided that unlimited government power is A Bad Thing to be strenuously resisted.

OK, maybe it's not much of a mystery.

Seriously though, one has to wonder why so many tecchies - who are, on average, very intelligent and somewhat resistant to regular bullshit - are signing this petition. The classic excuse comes from the role of IBM's equipment in the Holocaust, used by the Nazis to process the data around selection and slaughter of Jews in Europe. IBM itself acknowledges its role:

It has been known for decades that the Nazis used Hollerith equipment and that IBM's German subsidiary during the 1930s -- Deutsche Hollerith Maschinen GmbH (Dehomag) -- supplied Hollerith equipment. As with hundreds of foreign-owned companies that did business in Germany at that time, Dehomag came under the control of Nazi authorities prior to and during World War II. It is also widely known that Thomas J. Watson, Sr., received and subsequently repudiated and returned a medal presented to him by the German government for his role in global economic relations.
It's a bit unfair to single out IBM here. The premise is that equipment from an IBM-owned subsidiary was instrumental to the Nazis being able to kill Jews more efficiently. Nowadays, how would we feel if Syria's Bashar Assad used an Excel spreadsheet or two to organise slaughter of non-Alawite citizens? I'm fairly sure that Microsoft's Excel developers couldn't realistically be held accountable for this. Even if a Microsoft sales rep sold a 1000-seat Excel license to the Syrian regime, it would be a bit of a stretch to blame them for any resulting massacre. After all, the regime could always use OpenOffice for a free-as-in-beer-and-freedom solution to programmatic pogrom.

As you might expect from a Silicon Valley initiative, this is primarily intended as strenuous virtue-signalling. "Look at me, how right-thinking I am and how willing to prevent persecution of minorities!" Really though, it will have zero effect. The US Government does not contract out to random Silicon Valley firms for immigration and related database work. They have their own information systems for this, developed at horrific expense and timescales by the Beltway Bandit consulting firms and government IT workers. The US Citizenship and Immigration Services department isn't going to ask Twitter or a San Francisco start-up to develop a new immigrant tracking system - even though I suspect they'd get one with 10% of the downtime and 20% of the cost of the one that the Bandits will develop for them.

The most plausible concern of the signatories is the existing social graph and personally identifiable information in systems like Facebook and Twitter. Religion and national origin isn't stored systematically, and visa status isn't stored at all, but from analysis of posts and relationship activities I can imagine that you could fairly reliably infer areas of the relationship graph that are likely to be e.g. Guatemalan in origin and using Latin American Spanish as their primary language, working in low-wage industries, and physically located in Southern California (checking in from IPs known to be in LA and its environment). If you wanted to identify a pool of likely illegal immigrants, that would be a good place to start. Since Facebook already has this data, and sells access to parts of their information to advertisers, I wonder what these signatories are going to do about it?

$20 says "not a damn thing." They like their jobs and status too much. They won't find other companies as accepting of their social activism and public posturing. They won't take on new jobs targeting minorities, but then no-one sane is going to ask them to take on that kind of work because the D.C. consulting firms want the money instead and have lobbyists ensuring that they'll get it.


Expensive integer overflows, part N+1

Now the European Space Agency has published its preliminary report into what happened with the Schiaparelli lander, it confirms what many had suspected:

As Schiaparelli descended under its parachute, its radar Doppler altimeter functioned correctly and the measurements were included in the guidance, navigation and control system. However, saturation – maximum measurement – of the Inertial Measurement Unit (IMU) had occurred shortly after the parachute deployment. The IMU measures the rotation rates of the vehicle. Its output was generally as predicted except for this event, which persisted for about one second – longer than would be expected. [My italics]
This is a classic software mistake - of which more later - where a stored value becomes too large for its storage slot. The lander was spinning faster than its programmers had estimated, and the measured rotation speed exceeded the maximum value which the control software was designed to store and process.
When merged into the navigation system, the erroneous information generated an estimated altitude that was negative – that is, below ground level.
The stream of estimated altitude reading would have looked something like "4.0km... 3.9km... 3.8km... -200km". Since the most recent value was below the "cut off parachute, you're about to land" altitude, the lander obligingly cut off its parachute, gave a brief fire of the braking thrusters, and completed the rest of its descent under Mars' gravitational acceleration of 3.8m/s^2. That's a lot weaker than Earth's, but 3.7km of freefall gave the lander plenty of time to accelerate; a back-of-the-envelope calculation (v^2 = 2as) suggests a terminal velocity of 167 m/s, minus effects of drag.

Well, there goes $250M down the drain. How did the excessive rotation speed cause all this to happen?

When dealing with signed integers, if - for instance - you are using 16 bits to store a value then the classic two's-complement representation can store values between -32768 and +32767 in those bits. If you add 1 to the stored value 32767 then the effect is that the stored value "wraps around" to -32768; sometimes this is what you actually want to happen, but most of the time it isn't. As a result, everyone writing software knows about integer overflow, and is supposed to take account of it while writing code. Some programming languages (e.g. C, Java, Go) require you to manually check that this won't happen; code for this might look like:

/* Will not work if b is negative */
if (INT16_MAX - b >= a) {
   /* a + b will fit */
   result = a + b
} else {
   /* a + b will overflow, return the biggest
    * positive value we can
   result = INT16_MAX
Other languages (e.g. Ada) allow you to trap this in a run-time exception, such as Constraint_Error. When this exception arises, you know you've hit an overflow and can have some additional logic to handle it appropriately. The key point is that you need to consider that this situation may arise, and plan to detect it and handle it appropriately. Simply hoping that the situation won't arise is not enough.

This is why the "longer than would be expected" line in the ESA report particularly annoys me - the software authors shouldn't have been "expecting" anything, they should have had an actual plan to handle out-of-expected-value sensors. They could have capped the value at its expected max, they could have rejected the use of that particular sensor and used a less accurate calculation omitting that sensor's value, they could have bounded the calculation's result based on the last known good altitude and velocity - there are many options. But they should have done something.

Reading the technical specs of the Schiaparelli Mars Lander, the interesting bit is the Guidance, Navigation and Control system (GNC). There are several instruments used to collect navigational data: inertial navigation systems, accelerometers and a radar altimeter. The signals from these instruments are collected, processed through analogue-to-digital conversion and then sent to the spacecraft. The spec proudly announces:

Overall, EDM's GNC system achieves an altitude error of under 0.7 meters
Apparently, the altitude error margin is a teeny bit larger than that if you don't process the data robustly.

What's particularly tragic is that arithmetic overflow has been well established as a failure mode for ESA space flight for more than 20 years. The canonical example is the Ariane 5 failure of 4th June 1996 where ESA's new Ariane 5 rocket went out of control shortly after launch and had to be destroyed, sending $500M of rocket and payload up in smoke. The root cause was an overflow while converting a 64 bit floating point number to a 16 bit integer. In that case, the software authors had actually explicitly identified the risk of overflow in 7 places of the code, but for some reason only added error handling code for 4 of them. One of the remaining cases was triggered, and "foom!"

It's always easy in hindsight to criticise a software design after an accident, but in the case of Schiaparelli it seems reasonable to have expected a certain amount of foresight from the developers.

ESA's David Parker notes "...we will have learned much from Schiaparelli that will directly contribute to the second ExoMars mission being developed with our international partners for launch in 2020." I hope that's true, because they don't seem to have learned very much from Ariane 5.