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Alex's Occasional Journal Below are the 10 most recent journal entries recorded in the "Alexander G. M. Smith" journal:

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February 10th, 2014
05:35 pm

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C++ Template Wrestling

Had programming fun today with C++ template class method specialisation for some audio processing software.

To go from detecting DTMF (Bell's Touch Tone (TM) telephone dialing system) to also detecting low frequency subaudible sound signals, I had to change quite a few things (sampling rates (35hz audio needs to be listened to longer and slower than 1633hz audio when detecting a tone), batch sizes for filling the Goertzel filters, and related parameters), but the overall process was mostly the same. Rather than dynamically allocating buffers and making the filtering calculations take into account the differences at run time, I used templates to generate two versions of the code (templated subclasses of a common base class), handling the differences in buffer sizes, sampling rates and so on at compile time, making runtime faster.Read more...Collapse )

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December 24th, 2012
05:30 pm

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Haiku OS Progress
I've finally had enough time (after an unexpected summer of cottage repairs) to upgrade my newish (3 year old first generation Intel i5 processor) PC hardware to max out the RAM and use an SSD for booting. It's half set up, enough to run Haiku and Windows 7 and sometimes both via VirtualBox. Still waiting for Fedora 18 so I can experiment with Java and Ruby, as part of the learning side of my sabbatical. I'm pleasantly surprised to find that both Windows 7 and Haiku R1A4 can play the .MOV video files from my new camera, which my old PC (built circa 2000) couldn't do in real time, even in resolutions lower than 720p.

Of course, this means I'm stumbling into plenty of Haiku bugs (today's was file system corruption from indexing thousands of old e-mails as I was copying them over). I've reported some. Along the way, while setting Haiku and VirtualBox up, I posted notes and wrote a Haiku blog entry, in hopes that my experiences will help others avoid the tricky problems.

Meanwhile it's Christmas season and there are lots of parties to go to and even some theatre (excellent Miracle on 34th Street at the Gladstone, done as a live radio show). We have snow too, so it will be a white Christmas. All in all, a good year, despite the end of employment when Artech Studios closed its doors (not bankrupt - just hibernating) at the end of March. That kicked off a good summer (even ditch digging was strangely satisfying) at the family cottage.

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July 15th, 2012
03:29 pm

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Fedora 17 and RTL8139 Network Card Problems
Just in case someone else tries to install Fedora 17 Linux on an Intel 440BX based motherboard with dual 550Mhz Pentium III processors and a Realtek RTL8139 ethernet card, here are some tips for getting it to work.

The trouble seems to be with their new network driver system, the old one (Fedora 14) worked perfectly. It's now using the "8139too" driver and I suspect also a slightly different kernel infrastructure. Something's broken there that makes the system hang when too much network activity happens (relative to the speed of the CPU), perhaps a double interrupt or maybe DMA memory corruption. But it does hang dead, with no log or debug entries, even the caps-lock stops working (so it's not just X Windows).

First, install with the network cable unplugged. Otherwise it often crashes during the install.

Then once it is running, set the network speed to 10 megabits/second, rather than the usual 100mb/s. The command to do this is "ethtool --change p3p1 speed 10 duplex full", if the ethernet device is named p3p1 (use "ifconfig -a" to get a list of all network devices).

You can automate this by making an /etc/rc.d/rc.local file containing these two lines:
#!/bin/sh
ethtool --change p3p1 speed 10 duplex full

Though you may still need to unplug the network cable while booting since rc.local commands are run near the end of the bootup. This is particularly true if you have a busy network or the boot takes a long time (such as when doing a fsck to fix corrupted hard drives).

Hope this helps someone out there!

- Alex


Posted via m.livejournal.com.

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July 10th, 2012
06:36 pm

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Home Work
One thing about being on sabbatical is that I have time to catch up on old chores. Things like pruning an ewe bush (tree sized now), which I see from the rings was last done about 20 years ago. Some jobs seem small but get bigger, like adding a mail slot to the door. Easy enough, but then the door needs painting. A few days and several hours of work later...

On the plus side, I had a good Ottawa Fringe Festival (saw 49 plays) and had time to read a few books, though there's still a stack. Of course, having access to an iPad just slows things down, a Victorian murder mystery involving anonymous people over the telegraph lead to wondering about how the telegraph network was organised. Seems to have been hierarchical routing, based on some Russian documents I found (I assume that their network is a time delayed version of the Western ones). Oddly the first telegraph was Russian, predating Morse. Along the way past stock tickers (the earliest line printer) I ran into Western Union's Plan-55 automated switching center. I also found a PDF describing the equipment involved in 1957. Paper tape is used for buffering messages (at least today's electronic RAM is more sustainable!). Error handling involves a yellow light and a two tone attendant chime. There's even a fancy "director" box that used a two character code in the message header to route messages. Interesting stuff.

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May 31st, 2012
11:01 am

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Cloud Ship Traders Finished
We finally finished porting the Artech game engine to the iPad2, my part being the iOS side of things with Dave (our lower level engine guru) taking care of the OpenGL rendering glue. Though of course I end up having to fix things in the OpenGL side when iPad specific problems get revealed (that's how I got a crash course in OpenGL shaders and shader debugging).

Anyway, it all works now and you can see screen shots of the first game using it, Cloud Ship Traders, at http://www.artechstudios.com/cloudship/welcome.html It's a decorate your world and spin the resulting 3D globe with your fingers game. The decorating part includes painting islands with your finger and then placing all sorts of 3D objects (vegetation, buildings, animals to even a UFO) on it, while harvesting clouds for resources. You can download it from The App Store for free - I implemented advertising and in-game purchases for the money making side of things.

I'm taking a couple of years off for a sabbatical. This time I'm moving on to studying Ruby and Java with a plan to make a community theatre support system as an exercise in programming. Plus maybe some Haiku work too.

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October 19th, 2009
07:54 am

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Animation Festival 2009
Well, I'm back from almost a week of watching cartoons at the Ottawa International Animation Festival.

Lots of good stuff this year, my favourite being Consoul by Lasse Gjertsen (http://ottawa.awn.com/index.php?option=com_oiaf&task=showfilm&i=8323), with the music bringing back memories of the Amiga days and the action explicitly videogamey.

The new Wallace and Grommit were as good as ever in Nick Park's Loaf and Death, with a happy ending for a change, wonder if that will stick... Cordell Barker's Runaway was also good, and in the same showing so maybe that split the vote so that Madagascar from the first competition won the public prize.

Ah well, 25 shows in 5 days leaves a large pile of chores to do at home, or I can write a post and delay the work...

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January 30th, 2009
10:39 pm

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Annoyingly Cold?
One of my BeOS acquaintances was complaining about cold 45F temperatures keeping him indoors. Ha!

It's been pretty cold here too for the last three weeks, though at least not super windy. Typical morning weather was below -20C (-4F). So I didn't get all that much exercise, just quickly walked the shortest crunchy path to work. Not much snow to shovel either, just cold and clear. At least it's gotten warmer and it snowed in the last couple of days, and my arms ache now from the shoveling (did the roof too). But it's a good ache.

So, -10C/14F is a nice warm temperature for me - good enough to take the long way home, past various tempting stores. It's cool, but your face isn't frozen off by the wind. Now if it was 45F, I wouldn't have to shovel anything, it would have melted!

Ah yes, weather, the topic of conversation when there isn't much to say. :-)

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November 9th, 2007
10:10 pm

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Still not Much
Too much theatre and other fun activities, not enough time to write here or elsewhere. About one message every 6 months is my speed :-)

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January 2nd, 2007
09:40 pm

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Not Much Time
Not much time to post, what with work and relatives taking up more time than before. Got to get that BitTorrent client for BeOS updated...

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December 5th, 2005
07:16 pm

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Yet More Entertainments
Not too much to report - just too much entertainment in the last week. It started with Stones in his Pockets, a play about an American film company filming in Ireland. Of course, they want the hokey stereotypes, while the locals are a lot more modern. But still ordinary folk down on their luck (one had a video store that went bust, another visited New York and got home sick), happy to be extras on the film, getting 40 pounds a week and lunch, lusting after the female lead. There's a bit of Irish friction when work hours conflict with a funeral for a drug addict kid who loved the movies, was kicked out of the pub after annoying the star, and then walked into water with stones in his pockets. It doesn't end happily, but in a recursive twist the losers decide to write their own movie about the events. Oh, did I mention that this was played by just two actors, sometimes changing voices and posture as rapidly as modern TV commercial cutting does? Pretty amazing stuff. Particularly showing all the different kinds of happy happy joy joy when commanded to cheer when the regional lord was bought out by the good guy. The extras cheered miserably (funeral time) even after being threatened, then the actors turned into the crew manager and her assistant, showing them how to do it, then the directory and his idea of expressing joy. None of them got it right. Good acting!

I also saw the latest Pride and Prejudice. This time around I knew which characters were important and which should be ignored (otherwise it's just too confusing). Nice settings. The big impact for me was the demonstration of the difference between the poor family with lots of daughters and the rich aristocrat. He's got a huge mansion, with rooms dedicated to just a statue collection. Meanwhile the others have a farmyard right behind their decrepit country mansion. Anyway, glad I was able to follow the story and characters easily this time.

Finally, we had our company Christmas party on Friday afternoon and evening. This year we also went out to play curling (throwing rocks on ice) before the dinner. My leg muscles still hurt from running up and down the ice so much. Lots of fun. Plus I got a box of assorted beer, a copy of Friends (did some work on it), and half a gigabyte of photos and videos, which amused my co-workers today.

- Alex

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