The Colin Walls Blog

This blog is a discussion of embedded software matters - news, comment, technical issues and ideas, along with other passing thoughts about anything that happens to be on my mind.

23 February, 2017

There has been much discussion in recent years, in most Western countries at least, about marriage – what it means and how it might be reformed. Gay marriage has been discussed endlessly. Very recently, the topical discussion in the UK has been about whether a heterosexual couple might enter into a civil union; a court concluded that they could not. As I see it, all the discussion has been taking place amid great, heart-felt emotions and has been held back by long-standing traditions. All of this has resulted in the muddled thinking that leads to headlines in the less reputable parts of the media.

IMHO, a simple analysis of what a marriage is all about yields logical answers and the possibility for all parties to be reconciled [though this last bit is a long shot] … Read the rest of this entry »

20 February, 2017

If your embedded application makes use of a real-time operating system [RTOS], like Nucleus, you will need to learn the API – the Application Program Interface. The API is a series of function calls that enable the application code to make use of the facilities provided by the RTOS. These facilities include control of tasks, timing, inter-task communication and synchronization and memory management. The number of available calls may run into hundreds, as a modern RTOS offers a wide range of functionality.

Although C is the most widely used language for programming embedded systems, many developers are keen to use C++. This opens up an alternative way to interface with an RTOS … Read the rest of this entry »

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16 February, 2017

As I get older, I find that I am increasingly susceptible to strong emotions. I think it started 30 years ago, when I first became a parent. Having children stretches your emotions in every direction. I think that emotions are like muscles: the more you exercise them, the more agile they become. I can be moved by so many things – both in real life and movies etc. When we go to a movie, I am often pleased that we watch it in the dark.

An odd thing is that, although sad events can move me, it is seeing acts of kindness that gets to me most of all … Read the rest of this entry »

9 February, 2017

What do you do when you see a rainbow? I will tell you what I do: I just stand and stare. I have no idea how many I have seen in my life – it must be many hundreds – but I still stop. If I am inside the house and observe that it is raining and the sun is shining [and the angle of the sun is low enough], I rush outside to see whether there is a rainbow. Of course, on a good day, I will also see a fainter secondary rainbow. Once or twice, I have seen the faintest hint of a tertiary too. Even though I know that all I am seeing is the physics of light displayed on a grand scale, I still find a rainbow awe inspiring.

Pondering rainbows has got me thinking about colours in general … Read the rest of this entry »

6 February, 2017

Crystal ball gazing is, I feel, commonly a foolhardy activity. So often, I have heard so-called experts making complete idiots of themselves with their perspectives on a future that seemed unlikely at the time and turns out to be completely wrong in every detail. The world of embedded software is no different. Every few years a new fashionable technology is talked about everywhere, with predictions of the world changing completely, but it never quite happens.

I recently listened to an interesting podcast by a couple of well-known names in the business. A wide spread of opinions is part of life, and we should not always expect to agree with each other. I would like to suggest a different view … Read the rest of this entry »

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2 February, 2017

A while ago, I wrote about the benefits of saunas. In summary, it appears that regular use of a sauna can extend ones lifetime. Since I wrote that, further research has been reported that suggests that frequent sauna usage [several times a week] can reduce the risk of dementia by as much as 66%! I found the data to be quite compelling and will not let up on my use of saunas.

This encouragement made me wonder what the mechanism is for the benefits of a sauna and, as a result, I have come up with a whole new spa concept … Read the rest of this entry »

30 January, 2017

Not long ago, I was telling a friend about an iPad app that I had found useful. I commented that it was very reasonably priced at $10. They were very proud to tell me that they never pay for apps on their phone or tablet and only use free ones. I am always suspicious of the word “free”. I am a firm believer in the TANSTAAFL [There Ain’t No Such Things As A Free Lunch] principle – everything has a price, which may be monetary or something else.

I started pondering about how TANSTAAFL applies in the world of embedded software … Read the rest of this entry »

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26 January, 2017

I have some friends, a couple, who are keen tea drinkers – like many English people, of course, including myself. Whilst I am somewhat conventional and like my tea to have some flavor, they are rather odd and seem to want hot water that is barely stained brown. In a café, they will request hot water and a teabag on the side. The teabag is introduced to the water, but not long enough for a strong acquaintanceship to develop – just seconds. They can use a single teabag for 6 or more cups of tea, which is very economic.

I joked recently that what they drink is “homeopathic tea” and this got me thinking about complementary therapies … Read the rest of this entry »

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23 January, 2017

My latest article on has been published. This piece is the fourth installment of the RTOS Revealed series, which will continue to appear through 2017 and beyond. The series will cover every aspect of real time operating systems.

Tasks, the context switch, and interrupts

In this article, I take a further look at tasks and consider how the context switch works and how interrupts may be handled.

I hope that you find the series interesting and look forward to your input by comment or email or via social media.

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19 January, 2017

A while back, I wrote about the Repair Café, which is a monthly event at which a bunch of volunteers endeavor to repair items brought along by members of the public. I have enjoyed being involved with this venture and I am pleased to report on its continued success – we get around 50 “customers” at each session and they report a high level of satisfaction.

However, things have recently taken an interesting turn … Read the rest of this entry »


16 January, 2017

For many years, I would regularly be asked about networking options for embedded systems. Commonly, the query was about real time systems and how they might be connected straightforwardly. Most often, the question was “Can I use Ethernet?” This was an obvious enquiry, as Ethernet is a very well established standard. Also the hardware is widely available and competitively priced and it may be used as a vehicle for TCP/IP etc., which is familiar to many developers. The answer was never totally straightforward … Read the rest of this entry »

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12 January, 2017

I guess that I spend quite a lot of time thinking about Life the Universe and Everything. Starting out on a new year, I always try to be forward looking and positive – even if the state of the world is not so encouraging just now. Overall, I ponder about the fact that we all have a limited time in this world and we should all think about how to use this scarce resource … Read the rest of this entry »

10 January, 2017

Some exciting news today! Every year, publish their Top 10 list of embedded articles. This year I had two entries [#2 and #7], which is a very pleasing start to 2017. It is very interesting that my two articles are both from the RTOS Revealed series, which will be continuing this year, with the next article appearing very soon. It is great to know that they are popular. Perhaps, at the end of this year, I will have the #1 place!

Although I missed #1 this time around, it was great to see that honor going to my colleague at Mentor Graphics, Faizan Khan. Well done Faizan!

9 January, 2017

My latest video blog is now available. I am talking about memory architectures in embedded systems. Not strictly a software issue, but a topic that has a significant impact on embedded software development. You can see the video here or here:

Future video blogs will continue to look at topics of interest to embedded software developers. Suggestions for topics are always welcome via comment, email or social networking.

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5 January, 2017

We decided that we would like to get away for the Christmas and New Year holiday. We had two objectives: find somewhere where Christmas was, if not ignored, a lot lower profile than it is the in UK; get some sunshine. After some deliberation, we chose Sri Lanka [big island, south east of India – formerly called Ceylon]. On vacation, it can be hard to get much impression of the lives of the local people. Tour companies, hotels etc. provide a significant level of insulation, as they endeavor to provide the comforts and mod cons that western visitors expect.

It is always a great opportunity [for me, anyway] to spend time with a “local”, who is happy to tell you something about their way of life. For a few days, we had a driver – I will call him Mr. C. – who, apart from being a good driver on the rather chaotic roads, with an excellent knowledge of his country, liked telling stories. He had many stories and I was taking notes … Read the rest of this entry »

19 December, 2016

As I have been working on the RTOS Revealed series of articles in recent weeks, I have been thinking about the operation and functionality of operating systems. It is a very broad subject – hence the plans for a long series of articles – but I thought that some specific areas might be usefully discussed in this, more compact, context. A topic, that is not often considered, is the question of task identifiers … Read the rest of this entry »

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15 December, 2016

As this is my last “off-topic” posting of 2016 [there will be a techie one next week], I wanted to end the year on a high – of sorts. As I get older, I am increasingly affected – moved, really – by acts of kindness. I am most emotional when the kindness is directed to a stranger and the kind-hearted person has absolutely zero expectation of anything in return. This is a topic that I have discussed before. I am casting my mind back 10 years … Read the rest of this entry »

12 December, 2016

My latest article on has been published. This piece is the third installment of the RTOS Revealed series, which will continue to appear through 2017 and beyond. The series will cover every aspect of real time operating systems.


Tasks and scheduling

In this article, I take a look at tasks, threads and processes and outline their differences. The various types of task scheduling are discussed and some thought is given to the different states that may pertain to a task at a given moment.

You can gain access to the whole series by following this link.

I hope that you find the series interesting and look forward to your input by comment or email or via social media.

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8 December, 2016

I am generally of the opinion that marriage is a Good Thing, as it is a clear step towards the construction of a strong family unit, which is good for society as a whole. My view is shared by most mainline religions and is espoused by most governments, some of which provide fiscal incentives. [In the UK, there is a small benefit for low income couples, but richer people are likely to be fiscally penalized for being married – go figure.] It has been a while since I last considered matters of marriage and weddings for myself – I wrote about it at the time. But I have been contemplating the matter, as some family weddings are scheduled for 2017 … Read the rest of this entry »

1 December, 2016

I have always found the American Thanksgiving holiday rather annoying. I can never remember when it is and nobody gives me any warning. Then, all of a sudden, the world stops for about a week. Having said that, I am totally in favor of having a holiday in the middle of Fall [we have nothing between the end of August and Christmas]. I also admire much of the sentiment around Thanksgiving, as I perceive it. The focus on getting family together and lack of obsession with giving gifts is excellent. Last week, another aspect caught my attention … Read the rest of this entry »

28 November, 2016

ESCNext week, the California ESC event takes place and it is back in San Jose this year. I was planning to be there, as I had a paper accepted. Sadly, I needed to cancel my trip and a colleague will present on my behalf. Here are the details of the paper:

Dynamic Memory Allocation & Fragmentation in C & C++

In C and C++, it can be very convenient to allocate and de-allocate blocks of memory as and when needed. This is certainly standard practice in both languages and almost unavoidable in C++. However, the handling of such dynamic memory can be problematic and inefficient. For desktop applications, where memory is freely available, these difficulties can be ignored. For embedded – generally real time – applications, ignoring the issues is not an option.
Dynamic memory allocation tends to be non-deterministic; the time taken to allocate memory may not be predictable and the memory pool may become fragmented, resulting in unexpected allocation failures. In this session the problems will be outlined in detail and an approach to deterministic dynamic memory allocation detailed.

I am sad to be missing the show, but I hope it goes well. If you would like a copy of my presentation, please contact me via email or social media.

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24 November, 2016

It is my broad philosophy in life to be intolerant of prejudice and bigotry. I endeavor to see everyone as an individual and try not to make any assumptions based on the person’s color, gender, sexual orientation, nationality, religion, social status, body shape, intelligence or financial position. I will not claim to be 100% successful with this goal, but I do try very hard. I am very sympathetic to anyone who experiences abuse as a result of others’ prejudices. However, as I am white, male, heterosexual, British, agnostic, middle class, not fat, fairly smart and solvent, I have almost no experience of being on the receiving end of prejudice. This means that I have difficulty empathizing with a victim of prejudice. But that seems to be changing … Read the rest of this entry »


21 November, 2016

banner_referent_2016The embedded conference season continues and, next week, I will be in Sindelfingen, near Stuttgart in Germany for the ESE Kongress. This is an annual event that I have attended several times over the last few years. There is a small trade show – where some of my colleagues will be manning a stand throughout the week – and multiple streams of presentations … Read the rest of this entry »

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