How Yahoo has failed.

As many people have already read, Yahoo had a severe data leak in the past which resulted in ALL YAHOO ACCOUNTS being leaked to hackers. The hack includes sensitive personal information and includes an MD5 hash of the password you’ve used with Yahoo. This is a very serious issue as Yahoo has told me today in an email. It says:

Dear Yahoo User,
We are writing to update you about a data security issue Yahoo previously announced in December 2016. Yahoo already took certain actions in 2016, described below, to help secure your account in connection with this issue.
What Happened?On December 14, 2016, Yahoo announced that, based on its analysis of data files provided by law enforcement, the company believed that an unauthorized party stole data associated with certain user accounts in August 2013. Yahoo notified the users it had identified at that time as potentially affected. We recently obtained additional information and, after analyzing it with the assistance of outside forensic experts, we have determined that your user account information also was likely affected.
What Information Was Involved?

The stolen user account information may have included names, email addresses, telephone numbers, dates of birth, hashed passwords (using MD5) and, in some cases, encrypted or unencrypted security questions and answers. Not all of these data elements may have been present for your account. The investigation indicates that the information that was stolen did not include passwords in clear text, payment card data, or bank account information. Payment card data and bank account information are not stored in the system we believe was affected.
What We Are Doing

In connection with the December 2016 announcement, Yahoo took action to protect users (including you) beyond those identified at that time as potentially affected. Specifically:

  • Yahoo required potentially affected users to change their passwords.

  • Yahoo also required all other users who had not changed their passwords since the time of the theft to do so.

  • Yahoo invalidated unencrypted security questions and answers so they cannot be used to access an account.

We are closely coordinating with law enforcement on this matter, and continue to enhance our systems that detect and prevent unauthorized access to user accounts.

What You Can Do

While Yahoo already has taken action to help secure your account, we encourage you to consider the following account security recommendations:

  • Change your passwords and security questions and answers for any other accounts on which you used the same or similar information used for your Yahoo account.

  • Review your accounts for suspicious activity.

  • Be cautious of any unsolicited communications that ask for your personal information or refer you to a web page asking for personal information.

  • Avoid clicking on links or downloading attachments from suspicious emails.

Additionally, please consider using Yahoo Account Key, a simple authentication tool that eliminates the need to use a password on Yahoo altogether.
For More Information

For more information about this issue and our security resources, please visit the Yahoo 2013 Account Security Update FAQs page available at

We value the trust our users place in us, and the security of our users remains a top priority.

Chris Nims
Chief Information Security Officer

And yes, that’s bad… it’s even worse as the hack occurred in 2013 and it has taken Yahoo 4 years to confess everything about the hack. Well, everything? I’m still not sure if we’ve heard everything about this case. Worse, as Verizon recently took over Yahoo for a large sum of money, it could even have an impact for anyone using the Verizon services.

But there is more as people might not realise that the sites Tumblr and Flickr are also part of the Yahoo sites. We know that Yahoo is hacked but how about those other two sites? As I said, we might still not know everything…


About to drown by failing security.

Well, assume the worst. While we might be arming ourselves properly against any of these kinds of hacks, we also chain ourselves to the security provided by companies like Yahoo. And those security measures might not protect us against everything.

Fact is that Yahoo has become great and is becoming even bigger now they’re part of Verizon. As a result, all those 3 billion accounts are now owned by Verizon and we better hope that Verizon will use better security than Yahoo ever did. If not, anyone who ever used Yahoo, Tumblr, Flickr or Verizon might soon drown in security problems as their accounts have been hacked and they will continue to hack those.

Is there a solution to this problem? That’s a good question as there are many other companies that we rely upon for our security. Twitter, Google and Facebook are a few popular sites that are also popular targets for hackers. However, as long as these large corporations immediately notify all users if there’s a serious data breach and immediately respond by increasing security, the risks should be acceptable. What Yahoo did was wrong as it took 4 years before they finally admitted the truth!

So in my opinion, Yahoo has to disappear. It is unacceptable that any company with such a major role on the Internet regarding security is trying to hide the truth and keep people vulnerable instead of responding immediately. So instead of following Yahoo’s advise and change your password, I suggest everyone just close their Yahoo account. Permanently! You might still keep your Flickr and Tumblr account as those might not be involved in this hack but Yahoo should go.

And let’s hope that someone will improve the security on both Tumblr and Flickr as these services are highly popular all over the World.

The riddle of the Holy Men…

I generally stay far away from religion but I do like discussions about religion. And recently, I got involved in a discussion with some fanatic who “knew” he was right and I was wrong, as his Religious counselors have told him so. So I came up with a simple riddle which he could not answer.

It starts with three Holy Men and a large chest. And as I’m talking about religion in general, I make them of three different religions so we have a rabbi, a priest and an imam. But if you talking to a fanatic, make them all Holy Men for his specific religion.

Azra Yilmaz with Chest.png

The rabbi starts and opens the chest to look inside. Once he has seen what is inside, he closes the chest and tells you there’s a statue of a golden calf inside, with precious jewels for his eyes. He describes it in details and he sounds very convincing.

Next, the priest opens the chest and looks inside. After he has seen the content he closes it and tells you what is inside. It is a wooden cross with long, silver nails and a golden hammer. And he too describes it in a lot of details and sounds very convincing.

Last, the imam opens the chest and looks inside. He has seen the content and closes the chest and tells you what is inside. It is a marble statue of a horse with a crescent moon next to it made from pure silver. And it is described in details and also sounds very convincing.

Now, who do you believe? How do you know who is telling the truth?

It’s actually a simple riddle. But for some people, it is still too complex. When they’re from a christian background they are more likely to believe the priest. Jewish people would favor the rabbi. And muslims will believe the imam. But all we know is that at least two of these Holy Men are lying. And maybe all three of them are lying.

When you’re not biased by any religion, it becomes more challenging and you would try to find out how reliable these Holy Men are. You talk with them and look at their actions. Have they committed crimes in the past? Have they been caught lying in the past? And what are they describing exactly? And how about their family? Are they from families that have used lies and crimes in the past?

It takes some time to evaluate who is speaking the truth and as all three of them are very convincing you could just decide to believe all three. However, you know that two of them must have been lying, as not all three objects could have been in the chest.

Or could it? Could it be a magical chest which shows the content that the viewer wants to see? If so, all three of them would have spoken the truth but it requires the chest to be very special. And it makes the content of the chest questionable in value, as what worth does an illusion have?

Or you just don’t care about what’s in the chest. That’s actually the easiest solution. However, all three holy Men tell you that you have to believe one of them as your eternal soul would be in danger if you don’t. All three threaten you that you will go to Hell if you don’t believe in him or believe any of the other two. And that makes it even more challenging as you don’t want to spend your eternal life in Hell.

But if you don’t believe in a soul and eternal life then not even that matters. So the holy Men are telling you to believe them or else they will end your life. You have to believe one or choose death. And if you pick one, the other two will want to kill you, but the Holy Man whom you believe will try to protect you. With the threat of violence and danger for your eternal choice, you will be in big problems and will be forced to make a decision.

So, you wouldn’t make a choice on whom you believe, but you choose the one who is most beneficial for you and your family. You have no choice as you need protection and each Holy Man can provide protection. But when you chose one, the other two will become your enemies.

So you have a big dilemma. You are forced to choose one and will have to believe what he said about what’s in the chest. And this is the same problem as you see with religion. You have basically thousands of “holy men” claiming they, and only they, know the Truth and that you have to believe them, or else. And instead of having just two enemies you would end up with potentially thousands of enemies if you chose to believe one of them. They they will also be enemies if you don’t believe any of them. However, when you follow just one then he will likely protect you against the others.

Or not, as many holy men will actually use those who believe in him to convince them that the others are lying and thus deserve to die. They need to die because they don’t believe in what he is claiming. He knows the truth as he has looked into the chest. And you believe him because you think he’s trustworthy. Right?

Generations later, your children will continue to follow the children of this holy Man, as you’ve educated them to believe in what he told so they believe in what you told them. However, the Holy Man now has three children. And each child tells the story about the content of the chest differently again. One repeats what his grandfather has told. The second one adds a collection of gems and golden coins to the content. The third mentions flasks of wine as part of the content in the chest. And your children will have to make the same choice again as what you had to do. They have to solve the Riddle of the Holy Men.

And this explains why we now have so many different forms of religions. Why we have so many different opinions and don’t know what’s in the chest, as we don’t know whom we really can trust. This is a riddle that will repeat itself every generation, as new Holy Men will be born and each of them claim something different in the content of the chest. All these problems simply because we have to chose whom to believe.

Or do we? The solution of the riddle is actually quite simple. You yourself go to the chest and you yourself will open the chest and look inside. Then you will see what is inside. And when you want others to know what is inside, you will invite them to also take a look inside and keep the chest open. That way, every person can learn what is inside the chest without relying on what others claim they saw.

And that’s what’s science is! In science, you don’t present any beliefs but you show everyone the clear facts and allow them to evaluate the reality themselves by telling them what to do to see those facts. And you allow people to think for themselves and determine for themselves what they are seeing. You suggest theories and others might believe those theories or not. If they want, they can make up their own theories and that’s just fine. Everyone can see inside the chest and see the content.

So the answer of finding the truth is simple. You just have to look for yourself!

Nieuwe ABN-AMRO phishing email!

(Dutch warning about a phishing email targeting ABN-AMRO customers. As it targets Dutch people, I write it in Dutch. Sorry…)

Vandaag weer een spam-bericht in mijn spambox ontvangen waarin men weer probeert om mensen op een link te laten klikken. Ik heb het maar meteen als “Phishing” aangemerkt maar het is een beetje onbegrijpelijk dat mensen hier soms toch intrappen want als je goed oplet zie je dat er niets van klopt!2017-06-16.png

Eerst en vooral komt de email binnen op een account die ik niet gebruik voor deze bank, hoewel ik er wel een account heb. Dit toont maar weer eens aan hoe praktisch het is om je eigen domeinnaam te hebben met een catch-all mailbox zodat je een oneindig aantal email adressen kunt aanmaken.

Andere waarschuwingen zijn de spaties in de datum, de titel “Trouwe Cliënt” en enkele andere taal- en stijlfouten in de tekst. Zo klinkt “betaal kaart” best raar als het om een betaalpas gaat. Duidelijk een gevalletje Google Translate.

Ook het verhaal erachter is vreemd want de bank heeft problemen in hun IT systemen en daardoor moet de klant opeens actie ondernemen? En zolang dat niet gebeurt is de account geblokkeerd?

Interessanter wordt het als je de bron van de email beter gaat controleren. De afzender maakt gebruik van een sub-domein van en mogelijk is dit gehele domein een phishing-site. In ieder geval heeft het sub-domein een phishing pagina waarin het PayPal nabootst. Sowieso zou je PayPal als afzender verwachten, maar goed. Sommige mensen zijn idioten…

De email bevat ook een URL die verwijst naar een Russische website en dat verbaast mij niets. Russische domeinnamen worden vaak door hackers misbruikt omdat deze vaak eenvoudig te hacken zijn.

Als je verder de bron nakijkt zie je dat deze via de Duitse worden verstuurd. Dit domein is ondertussen al op diverse blacklists geplaatst wegens de grote hoeveelheid spam die ermee wordt verzonden.

Maar goed, de meest duidelijke detectie dat dit spam is, is omdat het in mijn spam-folder zit.

Delicious spam!

Once more, a post about spam. Why? Because I have one more interesting email in my spam-box, sent by someone who clearly is confused by the whole topic. So, here’s the email, with some annotations:


Why is it spam? Because Google Apps/GMail says it is. And google is often right in these things. And as I don’t know Adam Collier, nor see any name of his company, it clearly seems like spam to me too, from some wannabe web developer in India looking for customers without understanding the rules.

Why  from India? Well, the English writing is more British than American. The writing style is similar to how Indian spam is generally written, with only single-line paragraphs. The skill set used is also very common among Indian developers. The extreme politeness in the writing also is similar to what you see in mostly Asian countries, as people there are generally more polite. Then of course, it mentions India in the email too so that wasn’t difficult.

First of all, this email was sent from a genuine, free email address like those offered by Outlook, Gmail and Yahoo. I’m not going to say if it’s Outlook or not as I allow this guy some anonymity, even though his name is probably fake and the address already closed for sending spam. But for me that’s the first sign of spam. If it is sent from a free mail provider then you should make sure you know the sender before continuing! As usual, check the sender first for every email you receive!

Next is the address to where it was sent. While it seems to be my “info” account, it just isn’t! It was received by the account I used for my registrar and used in my domain registration where it is visible in the WhoIs information, including my name and some other details. The “info” address happens to be the address of some other website, who has also received this email. My address was actually part of the BCC header so other recipients would not see that I had received it. Smart, but it is to be expected from mass mailers as they would really piss off a lot of people if they only use the TO or CC fields, as many people tend to ‘Reply to all’ on spam messages, making even more spam.

So they got my address from the WhoIs database. So they should have known my name too! They just can’t use it as this is a mass email that’s probably sent to hundreds or even more people.As this spammer doesn’t seem to use any mass mailer application, I suspect that he just collected a lot of email addresses from interesting-looking domains and just mailed to them all from Outlook so the amount of recipients is likely to be hundreds, maybe thousands. Not the millions that more experienced spammers will use.

Interesting is how he’s called a webmanager in his email address while calling himself an online marketing manager in the email. No name for his business so maybe he doesn’t even have a real business. This could be a simple PHP developer who is trying to make a freelance web development business and is hoping to get some customers so he can expand his business. He might have a few friends who are also doing development and likely is a student at Computer Science classes in India who wants to put his lessons to the Test. This doesn’t look like a hardcore spammer, even though he is spamming. He’s more a lightweight spammer.

The prices he mentions are very reasonable. Then again, he basically uses standard frameworks like WordPress, Joomla, Magento and Drupal to build those sites which is generally not too much work. I call these “Do not expect too much from us” prices.

There is one major alert in all this, though. The grey line mentions a “Payment Gateway” which you should immediately distrust! Why? Because this developer is probably setting up this payment gateway and might have control over it later on. He could be siphoning off some of the payments made through it or even at one point empty all the money collected and put it in his own bank account! Good luck getting your money back!

Well, he could be honest but you should not take that risk to begin with…

It is interesting to see that he also provides Android and IOS applications. He seems to be specialized in PHP so he would need to know Swift or Objective-C to do the IOS development and Java for the Android development. Or have some other programming environment that allows him to develop for both platforms. He might be using Visual Studio with Xamarin which would allow him to focus on different platforms. Or he has friends who specialized in app development.

At the bottom of his email he tells you that this isn’t spam and that he actually hates spam. So if you aren’t interested you should just reply to him so he can confirm that your email address exists and is in use so he won’t be sending emails to it. Wait… Why does he need that? People who aren’t interested generally won’t respond! So he might actually be collecting confirmations for other purposes…

Anyways, it shows that many spammers are generally amateurs, not knowing what they’re doing. Some might work for some business and think they can promote it this way while others are just freelance developers trying to find a work in the current market. Both will generally learn that these kinds of emails are spam and generally end up being blacklisted or loose their free email account. The problem is not that they really want to spam people, but they are misguided in thinking that you can just send emails to everyone as part of their marketing strategy!

Unfortunately, it doesn’t work that way! If you send these kinds of messages unsolicited then you are spamming. If you seek new customers then you should start by registering your own domain name and provide proper information about yourself. Use your own domain name for sending emails and not some free provider and more important: use mailer software where people can subscribe and unsubscribe and only mail people who have subscribed! Also provide a simple web-based solution to unsubscribe as a link in your email. People might still consider it spam but at least the risks of being blacklisted becomes less as you’re conforming to the anti-spamming rules.

If you want to do proper business online then you need to be familiar with the rules. You should know about spam and how to avoid to becoming a spammer. You should have a clear profile of your business online, preferably under your own domain name. And you need to know about the legislations of the countries that you’re targeting like the cookie-laws and privacy laws in Europe. Thing is, if your site and services are targeting foreign nations then you are operating under their laws also! Never forget that!

And with that, this lesson ends…Marianne In Office.png

Donald Trump is NOT my President!

Bianca Delmonde for Shapeways_0001.pngThat’s because I’m Dutch and still rolling on the floor over this past election result from the USA, showing the utter madness that a Democracy can be, sometimes. Then again, the people in the USA didn’t have much to choose from, did they?

Many people were actually surprised that Trump got elected, which is strange as both the Democratic Party and the Republican Party are both about equally popular. The USA is basically a binary system, as there aren’t many alternative choices. Well, not voting is a choice, albeit a very bad one as you won’t get anything to say afterwards. But judging by the huge amounts of protests from the US population and all the bad things being said about Trump, it still is a bit of a surprise.

But again, binary system! The population of the USA is roughly divided into just two groups and many of these voters are unlikely to switch sides. There are, of course, many swing voters who can go either way but in general, both parties have their own loyal supporters. With no alternative choice than basically two bad candidates, many voters didn’t have any reason to switch sides, although Hillary Clinton did have a past history as First Lady and some Democrats might have wanted to keep her husband out of the White House.

So, today, Donald Trump will be crowned as the New President of the USA. So, utter chaos next?

No, I don’t think so. The Republican Party has been in power many times before and even had some very good Presidents in the past. Lincoln was a Republican. So was Eisenhower and Reagan. Reagan was an important factor in the end of the Cold War, even! Sure, he used to be an actor but in the 1984 elections, he pulverized his Democratic opponent Walter Mondale.

But this election was very close again. Clinton won the Popular Vote but in the USA that isn’t important. Trump just won the most electoral votes.

Then again, many people are also ignoring the fact that Faith Spotted Eagle also won one electoral vote during this election, thus becoming the first Native American to receive one such vote. Well, thanks to a faithless elector in Washington who was supposed to vote for Clinton…

Several other faithless electors decided not to vote for Clinton, which clearly tells me that she wasn’t a favorite among her own party. And that also explains why Trump got elected. Hillary Clinton just wasn’t the best candidate to pick for the Democrats.

First of all, Hillary Clinton would have been the first female POTUS if she was elected. But as the USA business world is still strongly male-oriented, I think her gender was already costing her some votes. She is also known as a former FLOTUS while her husband Bill was in office. And Bill Clinton had smoked a bad cigar while in office so it is understandable that some people would not like to see him return to the White House. Then there were some scandals about emails and an embassy in Libya and something involving the sexual abuse of minors and more fake news that put her in a bad spotlight, but that also happened to Donald Trump. Fact is, this election saw so much fake news that most people stopped believing all of it. They just relied on things they knew from the past.

I think Bernie Sanders would have been a much better choice anyway. Still, the Democrats choose Clinton and they’re allowed to make such mistakes. Considering that Hillary won the Popular Vote, it still wasn’t that bad.

So, what will happen next? Trump is a businessman and as such, he’s known to try and make companies more profitable. Sure, some of his companies went broke but overall, he has been reasonably successful with his businesses. Maybe with the bit of fraudulent support but still, he has collected quite a bit of wealth in his lifetime. Lost a lot too, though.

First of all, his tax plans don’t seem to be that bad. It seems that low-income Americans won’t even have to pay any taxes. And as he wants to reduce the number of brackets from 7 to 3, income tax should become a bit simpler for everyone.

He does want to repeal the Obamacare tax, though. Also called the Affordable Care Act, the Obamacare is considered extremely valuable for many Americans as it means that each and every one of them will at least have some minimum health care so people can get sick without going broke. But repealing the tax doesn’t repeal the act itself. In fact, Trump might find some other solution to fund this care, maybe change a thing or two, have it renamed to Trumpcare and POOF! Obamacare is gone! Yet the system would have barely changed and all Americans would still have basic health care.

Immigration is also a hot topic and Trump wants to build a wall to keep Mexicans out of the USA. And probably have Mexican companies doing most of the building of this wall as the Mexican government might want to subsidize the extra employment for their own population. A more strict policy on illegal immigrants might be useful as it could actually increase the wages of the legal immigrants! So, we’ll just have to wait and see what will happen…

Of course, Donald Trump has his site full with interesting plans that all sound quite nice. He’s a Master Merchant at this, knowing how to sell his ideas to the public, as he has done all his life with all his businesses. Trump is a Master at Selling and we can only hope that he will keep to his promises. But in the end, it isn’t Trump who is in Power. It is the Republican Party that is in Power and Trump is just their main spokesperson. He can’t do much that his party won’t approve, as they would just vote against him and probably even force him to step down, if need be. Barack Obama had similar problems as he had Great Plans, but could not get all of them executed as his own party and the Republican Party shot most plans down again. Donald Trump will have the same problem as the Democratic Party will try to resist any of his plans. So he needs the support of all the Republicans, else they just tip the balance against him.

The USA is just a binary system which makes it difficult to rule and have a lot of changes. Not many Presidents have managed to make a lot of changes to the whole system. Trump does have the advantage that the Senate is mostly Republican also so for a while, he will be able to execute some of his better plans. But in 2018 we will see the next Senate Election and as the Democrats won 3 seats in the past election, chances are that the Democrats will soon be in control over the Senate and thus stop whatever Trump has planned.

So Trump will have less than 2 years to prove his success as the next POTUS. And while many people hope he will fail, I realise that Trump failing as President will just bring more Chaos in the USA. So I’m expecting a few errors from Trump and a few successes and in 4 years, there will be new elections and by then, the Democrats will likely pick a better candidate.

Would be nice if Faith Spotted Eagle became the next POTUS, though. A Native American Female President! How cool would that be?

The Binary Search problem

Many developers will have to learn all kinds of algorithms in their lives so they can write highly optimized code. Many of these algorithms have long histories and are well-tested. And one of them is the binary search method.

The binary search is a fast algorithm to find a record in a sorted list of records. For most people, this is a very familiar algorithm if you had to ever guess a value between 1 and 10, or 1 and 100. The principle is quite simple. You have an x amount of records and you pick the record in the middle of the list. For guessing between 1 and 100, you would pick 50. (100/2) If it is the correct value, you’ve won. If it is too high, you now know the value must be between 1 and 50 so you guess again with value 25. Too low and you pick the value between 50 and 100, which would be 75. You should be able to guess the value in up to 8 tries for values between 1 and 100.

Actually, the binary search is actually the easiest explained as bit-wise checking of values. A single byte will go from 00000000 to 11111111 so basically all you do is a bitwise compare from the highest bit to the lowest. You start with value 10000000 (128) and if the value you search for is higher, you know that first bit is 1, else it needs to be 0.

Your second guess would either be 11000000 (192) or 01000000 (64) and you would continue testing bits until you’ve had all bits tested. However, your last test could also indicate that you guessed wrong so the maximum number of guesses would be equal to the number of bits plus one.

And that’s basically what a binary search is. But it tends to be slightly more complicated. You’re not comparing numbers from 0 to some maximum value but those numbers are generally a kind of index for an array, and you compare the value at the position in the array. You basically have a value X which could basically be any data type and even be a multi-field record and you have an array of records which has all data sorted for some specific index. And these arrays can be reasonably large. Still, the binary search will allow you some very quick search.

Now, the biggest problem with the binary search is how people will calculate the index value for the comparison. I already said that you could basically check the bits from high to low but most developers will use a formula like (floor+ceiling)/2 where floor would be the lowest index value and ceiling the highest index value. This can cause an interesting problem with several programming languages because there’s a risk of overflows when you do it like this!

So, overflow? Yes! If the index is an unsigned byte then it can only hold a value of 11111111 (255) as a maximum value. So as soon when you have a floor value of 10000000 (128) and a ceiling of at least (10000001) then the sum would require 9 bits. But bytes can’t contain 9 bits so an overflow occurs. And what happens next is difficult to predict.

For a signed byte it would be worse, since value 1000000 would be -128 so you would effectively have 7 bits to use. If the 8th bit is set, your index value becomes negative! This means that with a signed byte, your array could never be longer than 64 records, else this math will generate an overflow. (64+65 would be 129, which translates to -127 for signed bytes.)

Fortunately, most developers use integers as index, not bytes. They generally have arrays larger than 256 records anyways. So that reduces the risk of overflows. Still, integers use one bit for the sign and the other bits for the number. A 16-bit integer thus has 15 bits for the value. So an overflow can happen if the number of records has the highest bit value set, meaning any value of 16384 and over. If your array has more than 16384 records then the calculation (floor+ceiling)/2 will sometimes generate an overflow.

So, people solved this by changing the formula to floor+((ceiling-floor)/2) because ceiling-floor cannot cause an overflow. It does make the math slightly more complex but this is the formula that most people are mostly familiar with when doing a binary search!

Yet this formula makes no sense if you want a high performance! If you want a binary search, you should actually just toggle each bit for the index until you found the value. To do so, you need to know how many bits you need for the highest value. And that will also tell you how many guesses you will need, at most, to find the value. But this kind of bitwise math tends to be too complex for most people.

So, there is another solution. You can promote the index value to a bigger one. You could use a 32-bit value if the index is a 16-bit value. Thus, you could use (int16(((int32)floor+(int32)ceiling)/2) and the overflow is gone again. And for a 32-bit index you could promote the math to a 64-bit integer type and again avoid any overflows.

It is still less optimal than just toggling bits but the math still looks easy and you can explain why you’re promoting the values.

But what if the index is a 64-bit value? There are almost no 128-bit values in most programming languages. So how to avoid overflows in those languages?

Well, here’s another thing. As I said, the index value is part of an array. And this array is sorted and should not have any duplicate values. So if you have 200 records, you would also need 200 unique values, with each value being at least 1 byte in size. If the index is a 15-bit signed integer then the values in the array must also be at least 15-bits and would generally be longer. Most likely, it would contain pointers to records elsewhere in memory and pointers are generally 32-bits. (In the old MS-DOS era, pointers were 20 bits, so these systems could manage up to 1.048.576 bytes or 1 megabyte of memory.)

So, let’s do math! For an overflow to occur with an index as a signed 16-bit integer you would need to have at least 16384 records. Each record would then be at least 2 bytes in size, thus you would have at least 32 kilobytes of data to search through. Most likely even more, since the array is probably made up by pointers pointing to string values or whatever. But 21 KB would be the minimum to occur when using a 16-bit signed index.

So, a signed 32-bit index would at least have bit 30 set to 1 before an overflow can occur. It would also need to contain 32-bit values to make sure every value is unique so you would have 4 GB of data to search through. And yes, that is the minimum amount of data required before an overflow would occur. You would also need up to 31 comparisons to find the value you’re searching for, which is becoming a bit high already.

So, a signed 64-bit index would have records of at least 8 bytes in size! This requires 36.893.488.147.419.103.232 bytes of data! That’s 33.554.432 terabytes! 32.768 petabytes! 32 exabytes! That’s a huge number of data, twice the amount of data stored by Google! And you need more data than this to get an overflow. And basically, this is assuming that you’re just storing 64-bit integer values in the array but in general, the data stored will be more complex.

So, chances of overflows with a 32-bit index are rare and on 64-bit indices it would be very unlikely. The amount of data required would be huge. And once you’re dealing with this much data, you will have to consider alternate solutions instead.

The alternate solution would be hash tables. By using a hash function you could reduce any value to e.g. a 16-bit value. This would be the index of an array of pointers with a 16-bit index so it would be 256 KB for the whole array. And each record in this array could be pointing to a second, sorted array of records so you would have 65536 different sorted arrays and in each of them you could use a binary search for data. This would be ideal for huge amounts of data, although things can be optimized better to calculate to an even bigger hash-value. (E.g. 20 bits.)

The use of a hash table is quite easy. You calculate the hash over the value you’re searching for and then check the list at that specific address in your hash table. If it is empty then your value isn’t in the system. Otherwise, you have to search the list at that specific location. Especially if the hash formula is evenly distributing all possible values then a hash table will be extremely effective.

Which brings me to a clear point: the binary search isn’t really suitable for large amounts of data! First of all, your data needs to be sorted! And you need to maintain this sort order every time when you add or delete items to this record, or when you change the key value of a record! Hash tables are generally unsorted and have a better performance, especially with large amounts of data.

So, people who use a 32-bit index for a binary search are just bringing themselves in trouble if they fear any overflows. When they start using floor+((ceiling-floor)/2) for their math, they’re clearly showing that they just don’t understand the algorithm that well. The extra math will slow down the algorithm slightly while the risk of overflows should not exist. If it does exist with a 32-bit index then you’re already using the wrong algorithm to search for data. You’re at least maintaining an index of 4 GB in size, making it really difficult to insert new records. That is, if overflows can occur. The time needed to sort that much data is also quite a lot and again, far from optimal.

Thing is, developers often tend to use the wrong algorithms and often have the wrong fears. Whenever you use a specific algorithm you will have to consider all options. Are you using the right algorithm for the problem? Are you at risk of having overflows and underflows? How much data do you expect to handle? And what are the alternative options.

Finally, as I said, doing a binary search basically means toggling bits for the index. Instead of doing math to calculate the half value, you could instead just toggle bits from high to low. That way, you never even have a chance of overflows.

So, you want to be a software developer? Part 5.

In the first part I talked about resources. In the second post, I mentioned the need of logic and visualization. In the third post I talked about various platforms and the need to pick one to start with. In the fourth post I talked about modeling techniques, the development process and the need for documentation. And now I want to start talking about the first programming language that you should learn, plus the book that will teach you the basics.

This first language should be the Standard C language. Also known as ANSI C or ISO C, or just C. Developed by Dennis Ritchie, who died in 2011 but who also pioneered at developing a programming language meant to create operating systems. Or actually, just UNIX. And the reasoning behind this programming language was that this single language should be able to compile application for all operating systems and computer platforms and a piece of code should do exactly the same on all those platforms. And C supports so many processors and operating systems, making it one of the most important programming languages ever.

The book you will need is “The C Programming Language” by Brian Kernighan and Dennis Ritchie and is less than 300 pages with only 8 chapters and two appendices. And that’s another reason why you should start with C. This language is just plain and simple, yet contains the most important things you will need to learn about programming.

And remember that I have said that programming languages themselves are not important. Using the right technique is. You use languages like tools to solve a problem by making a product. This is also true for C. You should learn it but chances are that you won’t use this language that often. However, many principles in C are also common in other languages. And the C syntax has been borrowed by various other languages too so if you’re familiar with C, you will be able to handle quite a few other programming languages.

If you spend a day on each chapter and take two extra days for the appendices then you’d need 10 days to go through the whole book! In a normal work week, that would be just two weeks to learn a new programming language. The most complex part will actually be working with pointers and memory, which is just something you should know about before moving to other languages. You should understand the principles behind it.

Programming isn’t complex anyways. You’re generally just dealing with three things. You have basic statements, which e.g. assign a value to a variable or display a text on the screen. You have conditions where you will decide which step you will take next based on some value. And you have loops, which allows you to repeat a group of statements.

And there’s something that you can call a compound statement, which is basically a combination of statements, conditions and loops grouped together to create a “new” statement. In C, those are called functions but in other languages they’re also called procedures or methods. And you use these to add structure to your code.

And understanding structure is important in programming. Any data that your code will process will be in a specific data structure. And the code you write will also be in some structure. And even your computer in connection with other hardware will have a specific structure. And as a programmer you will have to use a lot of structures.

So, the C language is generally quite simple. But it is made more complex because the language allows programmers to create very badly structured code and with a lack of documentation, such code becomes extremely difficult to read. Still, C is extremely popular and it is likely that you will have to deal with projects that were developed in C.

For example, most operating systems. Linux, BSD, UNIX, OS X, IOS, Android and Microsoft Windows are all operating systems where the developers used C to write these. And a graphical library like OpenGL is also based on the C language. And these are all extremely complex projects but they have all histories that go back several decades. Even the old MS-DOS was a mixture of both C code and Assembly.

A game like NetHack is also written in C because it has a high performance and because it allows the game to run on basically any platform.

But I’m not telling you that you should learn C to use it, but to better focus on the basics of programming itself. Learn it, then focus om other programming languages, including the various Object Oriented programming languages.

After learning C you could consider C++, Java, C# or even languages like FreePascal, PHP, Python, Visual Basic and many others. But those languages all are way more complex than plain old Standard C. Especially the addition of OO in languages like C++ and Java will add quite a bit of extra complexity.

But C tends to scare off some people just because such complex projects have been created with it. And because some programmers have actually written cryptic C code to confuse others who try to read it. You can actually obfuscate your C code by removing spaces and line breaks and by using various shorthand notations and little tricks. There’s actually a competition to create obfuscated C code, held yearly since 1984!

Don’t be scared to learn C! Once you learn it you will realise that it’s actually quite simple. Don’t try to immediately write complex applications and especially don’t try to make complex GUI applications or 3D render engines with OpenGL because that is way too complex to start with. Start simple by creating console applications like Hangman, where you type letters to guess a word. Use a plain text as user interface since you will learn to make complex GUI applications in the future, once you’ve improved your programming skills! Focus on the C language first.