I should subtitle this post as “That’s not a pointer… This is a Pointer!” . In the previous two posts I showed how to import and export functions between Wasm and the host environment. This seems pretty safe, but can open up an attack vector which extern_ref shuts down. Let’s check that out…
In the last post I explained how compiled WebAssembly code could export functions which can then be invoked from the host, essentially using WebAssembly as a safe version of a shared object. But that’s only part of the story, at some point our WebAssembly code is going to want to call the host. Either to obtain a resource like a fopen function call, or as some sort of notification.
In most of the WebAssembly examples I’ve posted so far I’ve written simple, but complete applications, complete with a main function. But WebAssembly really comes into its own when you use it to embed third party code inside your application.
Ok folks. It’s late in the evening and I set myself the challenge of getting WAMR working on a Raspberry PI1. Rather than just share the tips and tricks, I thought I’d share a bit of my log book, and late night random thoughts as I get things going. Maybe this will be amusing to read? Anyway, it might help me remember in the morning.
You can think of signal’s like user space interrupts. Essentially the running application is interrupted, and a signal handler function is invoked. This function is passed some data to describe why it is being interrupted. Once the function is invoked it can process a response to this “signal”. You’ve probably seen this on Linux. Geeks for Geeks has a great description of Signals. They are effectively used to communicate some information to the running process, a common use case is sending a signal to notify a process that is about to be terminated, thus allowing it to clean up resources, closing file handles, etc.
It’s not unusual for your printer, or your fridge to have a small web server running. The embedded web server provides important control interfaces of these devices. It’s not just the fridge and the printer, but increasingly a large number of additional devices too, from milling machines on a shop floor, to smart pumps and electrical meters.
We all know that WebAssembly is great for the Web, but it’s also incredibly powerful in the embedded space too. You can compile Go, Rust, C++ and other languages for device families that don’t have compiler of build tools which support these languages. That’s in addition to the sandboxed and portable nature of WebAssembly of course.
There is a lot of nostalgia associated with retro computing, getting the chance to relive the halcyon day’s of our youth when we first got the chance to play with a computer can be a real buzz. But nostalgia is rose-tinted. The user experience of an Amiga or RISC OS, some of the first graphical user interfaces is arcane by today’s standards.
It isn’t often we get the chance to sit and think about the type of person we want to be, not about what is going on every day, but about how we would like to approach it.
My first PC was an Amstrad 5086, I had so much fun on that machine. Even without a computer game to play I used to spend hours configuring and customising it using a bit of software call Counterpoint.
Funny isn’t it how things seem to overlap. My previous musing was on Monkey Island a 16 bit MS-DOS game. It was just after writing that that I was flicking through Reddit when I came across a rather interesting post.
Although a huge long term fan of Monkey Island, it's taken me nearly 3 decades to complete Monkey Island 2. It was an amazing trip down memory lane. The game has such an amazing twist at the end, one I didn't know about for so long.
I think it is possible to save money on MQTT based IoT by employing a trick we used to use on Symbian mobile phones. It could save up to $30 per device per year, depending on your IoT plan.
Whoops, I didn’t hit post yesterday. Sorry.. I was busy selecting a Podcast hosting service. This morning I’ve got some time while my recording studio (the basement) is busy - the washing machine is on!
It was an idea that Dad and I had kicked about as a bit of thought experiment when I was in my late teens / early twenties. But there it was in real life. All set out in the shopping mall and implemented by a large clothing chain 20 years after we’d kicked the idea about. Funny. I had the sudden urge to tell him.
<figcaption class="wp-caption-text" id="caption-attachment-502">Dublin Airport before the sun rises</figcaption>
I’m typing this on a London bound flight. I’ve taken countless flights, but I’ve never done this before. I’m a little nervous, and a bit excited.
This has been a really busy week. Last week I was on holiday, as you can tell
from my previous blog posts, I’m a Brit, who firmly believes in the EU, and so
was pretty distraught at the results of the referendum. During the vacation I
got involved in a number of Facebook groups who are attempting to help ensure
that the UK reconsiders leaving the EU. Its a long hard struggle, but I think,
if we can pull it off it will be the national good.
The EU does a lot of work to help drive Science, technology and innovation across Europe, and I think in the mist of the Brexit debate this can get over looked. My day job involves working with these EU programmes, so I thought I’d share what I’ve been involved in, and have worked on.
11 years ago today, I woke with a hangover. As the room came into focus I looked about. Flash backs from the day before came before my mind, and the largest, biggest smile spread across my face. The booming headache was replaced with a serenity and happiness for which I felt immensely blessed.
From the initial diagnosis of Matthew’s infantile spasms right through to providing support for his eye rolls post discharge the guys at Temple Street Children’s Hospital have been amazing. The time has come were we can now give a little something back, and perhaps help other children and their families that are suffering from neurological conditions.
At first I wasn’t too sure what to make of it. An email explaining that a mobile application I’d written had changed someone’s life. But it turned out to be the single best piece of user feedback I’ve ever had and probably the best email I’ve ever received. It all started with an ultimatum from my wife, and a desire to create an app which would “scratch my own itch”….
I should have updated this blog sooner. It’s been over a month since Mattie was back at Hospital. In late April he returned for what was his final check-up with the Neurology team at Temple Street Hospital.
12 months ago the whole family enjoyed a Christmas steam train journey. It’s a fantastic trip organised by the Irish Train Preservation Society. Importantly at the end of the trip everyone gets to meet Santa. Last year Ben, our eldest son, had an absolute blast but in the middle of all of the excitement myself and Emma took turns holding Mattie as he shook with spasms. At the time he’d only just started his Sabril, was still bloated from the steroids he’d taken and suffering from conjunctivitis. The future felt very worrying. However, this year’s trip was very different!
Our last post closed with the wish that Mattie would walk into his next physio appointment under his own steam – well guess what? Our rock star baby did just that!
Myself and Emma have seen a number of people mention that their children are rejecting Sabril when it is mixed with water; they’ve ask about mixing Sabril with other drinks, and if this is possible. We thought we would share our experiences and the top 3 tips we learnt.
Ok. So if you follow me on Twitter, or we are friends on Facebook, your probably wondering what all my posts about email etiquette are all about. - Well let me explain.. it all started with an idea, which popped into existence, as all good ideas do, while suffering from a hangover.
It’s been a long time since we wrote about how Mattie has been getting on. A couple of weeks ago Mattie had Physio, and Occupational Therapy check-ups. Both went really well.
It’s Friday! - And for me, that’s the last day of the working week, the weather is great (for Ireland) and we’ve got a fantastic two day weekend ahead of us. To help celebrate I’ve been playing the Friday Movie Conundrum with some friends. The game is simple. One of us starts with a movie quote, and the other’s have to guess. Clues can only be given out if there is a lack of response. So folks, today’s quote is :
We had a brilliant time over the Christmas break, with two trips back to England one for new year, and another to catch up with friends in early Jan. Watching Matthew as he observed other babies, toddlers and assorted infants of all ages was fun. His excitement at wanting to get involved was really reassuring. Since my last post about Matthew we feel he really has made huge progress. However not all has been smooth sailing. During one of our recent ferry crossings I saw Mattie have a spasm, and in total we’ve seen about 10 individual spasms over the Christmas and New Year period. In fairness Mattie had also picked up some sort of virus over the Christmas period, which I’m sure didn’t help. Seeing the spasms made both Emma and I more keen than ever to hear what the doctors have to say about his progress, in particular if anything in his last EEG was concerning or worrying.
The problem with Hypsarrhythmia, the tell tale electrical activity present in an EEG which signifies Infantile Spasms, and can cause brain damage is that it’s transient; it comes and goes. It’s most frequent during tired periods before or after sleep, but it could happen at any time. The spasms we associate with the condition are just the physical side effect of what is going on in Mattie’s brain, they can be subtle and hard to detect. For months now we had been treating Mattie’s condition with the only indication of success being the lack of a spasm. Getting some hard data - a physical measurement via the EEG that the drugs are working is what both Emma and I were waiting for. If clear it would give us confidence that the electrical activity had returned to normal, and we’d not just missed another spasm.
It was about a week after Mattie’s last check-up. I was back home, my travelling temporarily suspended. We were in the middle of bath time, and Ben was still splashing about in the water. Mattie had already been been picked up and dried off. I was sheltering from a storm of splashing about when Emma poked her head into the bathroom, she had Mattie in her arms. “I just saw another one” she said. That is when we knew that the spasms had returned.
Halloween Top 10 It’s that time of year; October is here and in a few weeks we’ll be celebrating all things ghoulish with Halloween. But what would be the ultimate sound track for this month? - Is it possible to create a Halloween top 10?
I recently got some advice on how to research medical conditions from a parent who has a wealth of experience in health care systems and researching illnesses.
All the doctors we’ve spoken to about Mattie and his condition have commented on how little information is available. When we ask about treatments we get the same response - “we just don’t know”.
Emma (@emmawoods) and I (@mcwoods) have learnt a lot about Infantile Spasms over the last week. We are by no means experts - this is just something we’re working through at the moment. What we did learn is that the prognosis for children with Infantile Spasms increases dramatically with early treatment and hence early diagnosis. Unfortunately diagnosing Infantile Spasms can be very hard. To us parents it can look like something innocuous; “he’s sleepy, his head is too heavy” to “it’s colic”. Then even once the diagnosis has been made we had a steep learning curve – what is it? What are its impacts? It was, and still is confusing. About half way through last week Emma and I both realised that if we were struggling with this, then other parents probably will do to.
This time last week our little boy, Matthew who is not yet six months old was admitted to hospital and Emma (my wife) and I were trying to come to terms with what had happened.
I wrote this a while ago, while clearing out the study… while the study is now empty, there is now another room in the house currently stuff full of enough digital artefacts to make a silicone Tutankhamen envious.
It’s been nearly two weeks and I’m glad things feel like they are starting to get back to normal. Things have been a little nuts since we were burgled. There is more I’ve written, but don’t want to share yet. There are still many things being finalised with insurance companies and a court case pending and I don’t want to adversely impact them in anyway. But what I can tell you is that the last two weeks have been very unpleasant.
Driving down the street passing by offices for most of the major players in my industry as just surreal: eBay, Intel, NVidia, BroadCom.. even some new comers, Evernote.
[](/wp-content/uploads/2013/06/IMAG0144.jpg)A set up for travelling ergonomics
Ergonomics needn’t be expensive. I’m on an extended trip, where I’ll be travelling out of the office for about 3 weeks. During this time I’ve got a lot of work to do and will be spending a long time working on my laptop in Hotel rooms. I knew this was coming. So I packed a spare full sized keyboard in my check-in luggage - safely trucked between my jeans and t-shirts.
It’s ironic really. I’m in what could be considered one of the birth places of the modern Internet and yet I can’t get Internet access. As soon as I stepped off the plane, the data on my phone stopped working and it effectively became a dead weight in my pocket.
The rules are simple. The stakes high, and the competition tough. Prove your street cred with your friends and family - will your chosen tune out last the dreaded ‘bump’ ?!
They say that hindsight is always 20:20. It’s true. I’d been given 5 minutes in front of some of the most influential people and Europe to make my case, and 30 minutes after my nerve wrecking speech, I sat down and thought about everything I couldn’t cram into the 5 minutes I had been given.
The real beauty of Twitter is the ability to discover cool people, with shared interests and likes. It’s like finding that cool group of people in a crowded party. Meeting someone new and really getting to know an area they are interested in and sharing their passion.
Just before Christmas I listened to a fantastic post from @documentally about his trip to Sweeden, where upon a cold winters night he did a good deed for a local beggar and was rewarded with gratitude. I tried the same tonight on a cold trip home in London but was met with a remarkably different response.
“So what happened to Doggie?” - it was one of Mum’s first questions during our phone call. I had been recalling how my one year old son had just managed to walk across our bed and pull down all of the cuddly toys myself and my wife keep on our headboard. Doggie had been sitting on the headboard when he was attacked.
I’ve got my son, Ben in my arms while in trying and failing to run a bath for him. Ben has other ideas and he’s trying to break into my aftershave bottle. The door bell rings and brings someone unexpected, who through a random act of kindness will help us have a good Christmas.
[See the full gallery on Posterous](http://mcwoods.posterous.com/mince-pie-month-begins)
I love mince pies. So much so that I limit myself to only eating them in December. Today is December 1st so it was with great excitement that I broke my mince pie fast and opened a packed of Mr Kipling’s best and was instantly disappointed.
It all started during the Basketball final during London 2012. Now @emmawoods is pretty good at basketball, she even got the the trails to play for the Ireland under 19 team, and it runs in her family, an elder sister of hers played for Ireland’s full team, and even got to scholarship to the USA based on her fantastic basketball ability. I on the other hand played Rugby at school, and not brilliantly. I did once or twice try my hand at basketball….
Suddenly it went quiet… I tried to sleep, but memories of dental pain ran through my mind and I tried my best to loose myself in the in the slowly rocking blanket of calmness I’d found on the ferry, but it didn’t work… that is when I discovered some new music.
I’m all for efficiency and reuse and recycling, but seriously some of this is just plain daft, the rewiring of the gates at Dublin Airport and the dodgy looking stuff here in the hotel in Madrid are nuts.
**p39.mov**
[Watch on Posterous](http://mcwoods.posterous.com/feel-this-barcelona-mwc)
After the flight from Dublin my dash to the local bathroom in Barcelona resulted in a few chuckles at what I thought was Spanglish. The handle on the inside of the door was adorned with the words ‘feel this’ yes I must admit I did giggle and I even shared an image on twitter. By the end of my two days at Mobile World Congress, ‘feel this’ may have been one of the most poignant messages I took away.
Airport information told me the old available WiFi in Madrid airport was only available as a poor signal from the far end if the terminal. Complete with no seats.
[See the full gallery on Posterous](http://mcwoods.posterous.com/in-madrid-at-last)
Some pretty rough turbulence on the way over - even the pilot seemed surprised by it. But I’ve arrived, bed beckons and the hard work kicks off tomorrow !
Up for the red eye flight to london a full day of meetings and then flight out to Madrid this evening. I’ve a feeling it’s going to be a long day today.
I got the chance to take a walk through the grounds at carton house while Emma has her spa treatment. Managed to grab some nice smartphone snaps of sunset - all we need now is a bit of snow and it’ll be very festive !
I’ve recently finished Uncharted 3, man I loved it. I got hooked on the story, the interplay between Drake and Sully was great. I even enjoyed the back story on how the two met and the lightly touched on, but skillfully told love story.
[See the full gallery on Posterous](http://mcwoods.posterous.com/tough-job-being-a-mini-scientist-judge-irelan)
Today I got the chance to judge at the Grand Final of Intel’s mini scientist competition. It’s a national competition run by Intel to encourage primary school children to get involved with maths and science. It’s open to schools across the country.
[See the full gallery on Posterous](http://mcwoods.posterous.com/aerlingus-extra-leg-room)
Thank goodness this is only a short flight!
Just to give you all some perspective, I have short legs (28”) and yet me knees are touching the seat back in front of me. Can this be safe? Let alone healthy on longer flights?
Ran out of time, but really enjoyed painting it. My first time painting with acrylic paint too! Unfortunately I have set a high bar for the house back home!
I sketched the bottom giraffe first and my sister in law asked for something more cartoon, so I did the top one. We asked my niece which one she liked…. The bottom one, except it has to be pink. Awesome.
US Airways changed the plane we were due to fly on. As a result the seat plan changed and the ‘computer’ automatically picked myself and my pregnant wife seats 15 rows apart. This all happened last night and we didn’t have the chance to fix it before arriving at the airport. Bummer.
<figcaption class="wp-caption-text" id="caption-attachment-502">Dublin Airport before the sun rises</figcaption>