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.

Apr 28

How to solve Apple’s Pro Video Formats 2.0.1 constant update loop.

A software update which was made available by Apple earlier this month causes some users machines to get stuck in a constant update loop. As soon as you install the update it re-appears as available for update. If this affects you, then there is a simple solution. Continue reading

Apr 24

What makes apple’s new watch tick?

Want to know what makes Apple’s new Watch tick? Then read on to take a look inside.

Continue reading

Feb 04

Apple’s new SpaceShip building takes off. (Video)

Construction work on Apple’s new “SpaceShip” headquarters building has begun, demolition is complete and the new circular campus building is beginning to rise from the ground. This video shows where it’s up to so far, and you can also see the huge car park building. Continue reading to see the video. Continue reading

Sep 11

mDNS / Bonjour tool for OS X Now Available in App Store.

My new mDNS Tool for Mac OS X is now available in the Mac App Store.
View it on the App Store or search the Mac App Store for “mDNS Tool”.

Screen Shot 2014-09-11 at 09.23.57

The tool allows you to browse and find all the mDNS / Bonjour services and devices on your network. Bonjour is Apple’s name for their implementation of mDNS, which is used to advertise and locate devices and services on the network.

  • List all mDNS / Bonjour devices on your network.
  • Find the address of devices and services.
  • See all the device details, not normally shown in network browsers.
  • Find IPv4 and IPv6 Addresses for devices.
  • Copy details to the clipboard.
  • Simple to use.
  • No drivers or libraries required.



Feb 28

Logitech M570 Teardown and Repair

The Logitech M570 is one of very few thumb-operated trackballs on the market. For anyone, like me, who suffers from RSI in the wrist, it is an ideal replacement for a mouse as it removes all the moving back and forth – your wrist stays in one position and does not move when using it.

I have had several of these over the years and they have all suffered from the same problem: after just a few weeks of using them, they start to develop problems like double-clicking and dropping files when you are trying to drag. I posted a blog about this earlier. You can read it here.

In this post we will teardown the M570 and repair the cause of the problem.

Continue reading

Nov 20

Setting up the root user in Mac OS X

For information on how to enable the root user in Mac OS X Mavericks, see this tech note from Apple:


And for doing the same with OS X Mountain Lion, see this tech note:



Nov 20

Backing up my BugZilla database

Now that I have bugzilla set up, my clients are starting to use it. It’s a very useful tool for logging bugs, feature requests and test results. The clients get kept up to date on what I’m doing, and I don’t have to remember every thing as it is all kept in the database.

That means that the database has to be protected from loss or damage by taking regular backups.

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Nov 19

Installing BugZilla on OS X Mavericks – Updated

Finally I have gotten round to finishing the install of BugZilla on OS X Mavericks (OS X 10.9)
and I’m pleased to say it is working well.

There were several hurdles along the way, but the main one which kept bugzilla from running was that the MySql library, required by perl to access MySql was installed in a different place than the _www user group expected to find it.

After installing Perl, MySql and BugZilla the main bugzilla install script kept failing with errors trying to connect to the MySql database.

Continue reading