Feb 03

Calculator in Apple’s OS X El Capitan cannot perform basic maths!

I have discovered that the Calculator app that ships with OS X El Capitan cannot do some pretty basic programmer’s maths. Being able to add and subtract in Base 10 (decimal) and Base 16 (Hexadecimal) is a pretty basic requirement of any programmer’s calculator. Developers use these number systems all day long, and the Calculator App in Mavericks does claim to be able to. Except it can’t do the most basic subtraction.

Lets start with a pretty basic example in decimal. Open the calculator app and make sure it’s in “basic” mode. (CMD+1). The try this sum:
0 – 5 = ? the answer is -5, and the calculator gets this one right!

Screen Shot 2016-02-03 at 10.29.36

Now, with the answer still showing press CMD+3 to take it to programmer’s mode. You should see the display change to 0xFFFFFFFFFFFB – which is correct – that’s how you show -5 in 64-Bit Hexadecimal. Good so far! (click any image for a full view)

Screen Shot 2016-02-03 at 10.32.49

OK, so now hit the AC button to clear everything and we’ll try again, this time starting in Programmer’s mode.

Enter the same sum again 0 – 5 = and what answer do you get? You will get 0x7FFFFFFFFFFF – which is totally wrong. It’s not even one of those “oh I see what it did” type of wrongs, it’s just plain old wrong.

Screen Shot 2016-02-03 at 10.36.02

And just for fun, the same thing in Windows 10’s new calculator app..
Oh look, it gets it right!

Screenshot 2016-02-03 10.38.59

For the above tests, the most recent publicly available released version of OS X El Capitan 10.11.3 was used.

Hong Kong trip postponed.


I was supposed to travel to Hong Kong on Saturday 11th October to attend HKTDC, but I had to pull out due to a foot injury. Now it looks as though that might have been a provident decision, given the current unrest in the area.  Continue reading

Sep 22

Stay safe from high quality phishing email scams.

Today I received an email on my BT Internet email account which looked bona fide, but it was a phishing scam. Here I describe how to spot the few clues, to make sure you don’t get caught out. Continue reading

The difference between the UK, England and Great Britain explained.


Ever wondered what is the difference between the terms “Great Britain”, “the United Kingdom” and even “England”? Well here’s the answer…


Aug 27

How To spot a fake or phishing email.

Here is our cut-out-and-keep guide on how to spot a fake or “phising” email.

A ‘phishing’ email is one that purports to be from someone you do business with, like your bank, Apple, a high-street store or online store, but is in fact a fake email trying to get you to hand over your identity, passwords and/or debit & credit card details.

As an example, take a look at this email which is doing the rounds at the moment: (this is a picture of the email, not the email itself, so it’s safe!).

Screen Shot 2014-08-27 at 16.02.36If you had received this email, would you have clicked on the “Update Now” link?

It looks genuine enough, and if you click on the “Update Now” link in the email it would have taken you to this website: (again, this is a picture of the web site, not the site itself).

Screen Shot 2014-08-27 at 16.16.52

It all looks genuine enough, but if you were to fill in this form, your Apple ID would be taken over, and you bank account cleaned out within minutes. I won’t publish the link that was embedded in that email, that would just be silly, but it took you to an address very similar to this “www.udumy.ru/themes/Similitude07_div/forum/appel/” – which should raise alarm bells, because it looks nothing like the usual web addresses for Apple – and they even spell ‘Apple’ wrong in the link.

So how can you tell if an email is genuine? Well, lets take a look at the clues in the original email.

Here is our cut-out-and-keep guide to spotting the fakes:


The simple rule is this:
Never trust any email that asks you to verify your identity or payment details. If you think it might actually be genuine, because you are (for example) expecting an account to expire, then instead of following the links in the email, use your normal routes for contacting the company. Don’t use any email addresses or phone numbers on the email, they might be fake too!

Aug 15

Galileo GPIO Timing & why it doesn’t work for some.

The Intel Galileo is has Arduino UNO compatibility, yet often I see queries from someone asking why their favourite Arduino Shield won’t work, or why an interface they have made which works on other Arduino boards, doesn’t work with Galileo. Often they say Galileo is no use, or Galileo doesn’t do what it claims, or Galileo is slow. So why do some Sketches and Shields not work as expected, when using GPIO on Galileo? Read on for the answers…

Continue reading

Jun 03

Time travel will happen – and I can prove it.

About 14 years ago, around about the year 2000, I wrote an article for a magazine called ‘Develop‘ – it was a magazine for developers in the console game industry. The magazine printed it, but they called it the ‘the Oddview’ and the editor (Owain Bennallock) followed it with a sly comment that said something along the lines of “if anyone else has an odd view of the future, write in and let us know”. The thing is, my vision of the future came true. I have another vision of the future to share with you, I think you’ll find it interesting and maybe a little scary at the same time. It will come true and you will remember where you heard about it first.

Continue reading