Stefano Rivera (Posts about me)

Ravioli and More Electrical Disasters

Stefano Rivera — Tue, 23 Dec 2008 20:12:32 GMT

This afternoon, I went to my parents' house to make Pasta for the Christmas Eve dinner. It's one of the few family traditions we have; almost every year we dust the dining room table down with flour, get out the pasta rolling machines, and make a few hundred ravioli. It takes the best part of an afternoon, you have to work quite fast, and the final product doesn't keep very well. They need to be stored separated on floured trays, and turned twice every day to avoid sticking to each other or the trays. However, they should taste delicious tomorrow night. Some past photos.

In-between making ravioli (and fixing computers), I was dispatched to fix the broken light above our work table. As suspected, it was the dimmer fuse that had blown (in fact, decimated). So, in with a new one, and I had to re-mount the dimmer. I could see that the dimmer was terribly designed — the top mounting screw comes really close to the circuit board, and right at the edge of the board is the un-insulated fuse holder. This got me mumbling something about bad design, and very gingerly using insulated tools on the screw. Here's a diagram:

Obviously, during the mounting, the mounting tab will come really close to the board and fuse holder. Naturally, that happened, and there was a very loud bang. The circuit board trace next to the holder had burned through. Hmph. How one earth did they get this certified as safe for home use?

I suppose it's also another reminder not to work on live circuits. I've had enough of those reminders in my life...

Graduation isn't straightforward

Stefano Rivera — Mon, 03 Dec 2007 16:14:25 GMT

I haven't blogged in a while, since exams are now over, and I have less urgent procrastination needs. I maintained an average of more than 1 post / day at the hight of my studying :-(. In fact, I've been recovering from exams, and trying to catch up with the rest of life that I had to put on hold all year. And more recently, an insane RSS feed and e-mail build-up from a week of ignoring them while I was catching up with my life.

So, no posts doesn't mean life has been uneventful. I've been:

out almost every night last week
picked up wall climbing again (thanks Ken) and through it found some people I haven't seen in ages (Hi Chris)
elected the Chairman of CLUG
involved in a spat with ICTS (the topic of a future post)
spending at least a day encoding GeekDinner videos (using Makefiles to allow encode video in parallel on dual core machines, and using a handful of machines to do the work saves a lot of time), and finally
almost not graduating. (the rather ranty point of this post)

This was my third your of an Information Technology BSc (specifically Computer Science and Electrical Engineering). I've had good results most of the time, but I'm not class medal material.

In first year, I slept through almost all of my Statistics lectures (3rd lecture in day, after an insanely early start - I was usually exhausted, and well primed for sleeping). Come the end of the year, somehow, I didn't realise how meagre the exam's formula sheet was going to be, and failed the course horribly. I swore I'd never do Stats again, making up the points with another, more interesting course. I didn't get a chance to do this in 2nd year because I failed and had to repeat another course due to bad timing between deadlines and my best friend's tragic death in a hiking accident.

This year, I had a reasonably heavy course load, with the 3rd year CS courses, and a composite EE course made up of two 3rd year, and a 4th year course. On top of this, I had to fit in something extra to make up Stats. The only extra course I could schedule was... Stats. I spent an afternoon running around, and computing schedules, but there was no alternative.

This time around, I actually enjoyed the Stats - it was (partly) very well lectured, and I already knew the basics of the course-work. I read the textbook, crammed the necessary formulae for the exam, and wrote it, all a monstrous 6-hrs-of-exams day. And that, I thought, was that.

I kept myself busy for the next couple of weeks, and then wondered to UCT on results-day, to see what I'd got. I was top of the (admittedly small) class for my EE, and scraped a 1st in CS, great! Next I head to stats, and I see "DPR" next to my name instead of a mark.

DPR means that I didn't complete the require coursework. The list of who got DP (Duly Performed), and who didn't (DPR) goes up a week or so before exams begin. Somehow I hadn't noticed that I hadn't got DP (I'm pretty damn sure that I checked the relevant noticeboard, I'm good like that). DPR means don't write the exam, it won't get marked, you've already failed. But somehow it'd escaped me, and I'd written it, and now I was not going to graduate. I couldn't believe that I was DPRed, but it was possible - I'd screwed it up before, and could have failed all the tests (I'd hadn't seen all the test results yet).

So, the next morning, I raced off to see the Stats course convenor. We sifted through paperwork, and found the problem - I didn't have a mark for one of the tests, and for DP you need to write all the tests. Eventually we found the attendance slip that proved I had written it, which meant either I'd escaped the test venue with my test-paper, or the department had lost it before it was marked. Fortunately, my exam had been marked, I'd passed, and they believed that I'd written the test. So after an agonising day's wait, I heard that the Head of Department had approved passing me, as if I'd missed that test on medical grounds. I've since heard that University policy dictates that the department must take the blame unless they can prove it was me (it wasn't).

Phew.

That doesn't mean everything is solved yet, I was recommended to do an elective in 1st year, that is now no longer sanctioned for my course. It usually causes me hassles during registration, and might come up again now, but I think I can safely assume I'm graduating...

Planet Geekdinner for *camp

Stefano Rivera — Fri, 09 Nov 2007 21:54:59 GMT

I've updated planet geekdinner to pick up *camp posts.

As usual, as long as your post mentions the words *camp or geek-dinner, it should make the planet. We can no longer use tag feeds, as "geekdinner" and "*camp" are generally separate tags.

For regex geeks, the regex is ([gG]eek[ -]?[dD]inner|([sS]tar|\*)[ -]?[cC]amp)

On another note, I don't know if I'm going to make star-camp - I might well be away that weekend. But hopefully I'll be there.

CLUG Talk videos

Stefano Rivera — Wed, 10 Oct 2007 11:22:24 GMT

CLUG is one of the more active LUGs around, and has had fortnightly meetings with technical talks consistently since at least 1999 (the extent of our records, and my involvement).

While this heritage is a testament to a strong LUG, there are only about 20 people who regularly attend meetings, and thus get the benefit of these talks. With a LUG membership of around 800 (my best estimate from mailing list figures), this is a tiny fraction of our community. People who can't make it have been requesting videos of talks for a while, and recently Jonathan Carter brought his camera, and we started playing with videoing them. He has been stuck in Johannesburg for a few weeks and left me his camera, so I've been playing around with encoding.

So far, the lessens learned:

Video quality: A camera, high up at the back of the room produces reasonable, compressible video without having to have someone pan around following the presenter.
But the built-in microphones on a cheap camera just aren't effective at that range (especially when you've got a quiet speaker).
Audience questions are hard to record.
Audio editing is do-able, and necessary. But so far, we haven't ventured into video editing (on linux, this isn't trivial).
You can't normally read all the slides (or demos) with SD video. At full PAL resolution, most slides are legible. Screen-capture is an option, but most presenters make their slides available, which is far more bandwidth efficient.

Our progress so far is these procedures, and these videos: UK, ZA. We are using Ogg/Vorbis/Theora, and 3 different qualities of video. The three qualities are overkill, but I'm still experimenting with settings. I'd like some feedback - especially from a codec expert :-)

We lost Wikimania 2008

Stefano Rivera — Tue, 09 Oct 2007 18:05:21 GMT

We lost Wikimania 2008, quite badly (by points). I'm obviously sad, because I was hopeful, and had invested the odd weekend into comparative flight pricing, bid editing, and sitting on the phone...

According to the published criteria, we should have done well. Somehow we managed to score lower than Alexandria on "rotation" which is odd because Wikimania has never been held in the Southern Hemisphere.

I'd have liked too see the IRC log from the judges meeting, to see where we lost our points, but of course that isn't going to happen, so we'll have to work it out ourselves, by comparing the bids.

In retrospect, our bid wasn't that great. We were pinning more hopes on our location, and Cape Town's attractions, then on the bid itself. It was expensive, last-minute, and lacking sponsership & good accommodation. By losing, we got our chance to get it right next time.

The good news, is bidding opens for Wikimania 2009 almost immediately. I don't know what the chances are of 2009 being in Africa again, but I'm assuming we are going to bid, if everyone can pick themselves up and get going on it. To do it, w e are going to need firm sponsors. Find any friends you have corporate contacts, and twist their arms.

Petrol Theft?

Stefano Rivera — Sun, 16 Sep 2007 17:59:17 GMT

Yes, petrol is now expensive enough, that it's worth the risk to steal it from someone else.

On friday night, some bastard cut the fuel lines of all 4 cars parked outside our house. We are probably the only people on our street who don't park behind an electric gate, because our driveway only has space for my parents cars on the property. My car lives on the council-owned part of our driveway.

I found out because my sister (who'd been visiting to use our Internet connection) broke down on the way home. With her car, this is perfectly normal, and to be expected. I went out to tow her home (she was only about a 500m away). I couldn't find the tow hook on my car (my Golf has removable tow hooks, and somebody once broke into my car and stole the jack-set containing the removable hook), but I did notice that my car was trailing a line of petrol... odd... I went back to borrow my father's car (with a tow-bar), and towed her home with that.

She was going to borrow my mother's car (she usually does that when my mother is away, and her car breaks down), but noticed that there was a pool of petrol under it, too. Very odd...

At this point, I put 2 and 2 together, and found that all of the cars had cut lines. In the case of my father's car, they hadn't got a fuel line, but had god a brake sensor line instead. (Apparently VWs all have the fuel lines on the outside for safety, so they are the easy targets). On my car, they had only cut the fuel return line, so it could still drive, but would trail petrol.

The police were quick to come, but not very helpful: they said they'd never seen anything like it. They were thinking vandalism or neighbour issues. The questions were "Do you have a dog?" "Do you get on with your neighbours?" etc. You can tell what the normal problems in our area are :-)

The AA refused to come and help or tow the cars to my mechanic, saying the damage was an "insurable risk". I thought most car problems were "insurable risks" and the reason one has AA membership is to sort things out afterwards? This refusal by them is unacceptable, what if it had happened when I was parked somewhere else? Would I have to get my car home by myself?

Fortunately my grandmother's car was in storage in her garage, and I could rescue it. My sister stole her mother's car, too. But I've now got a whole lot of paperwork to sort out, and 4 dead cars to get repaired... As I said, "Bastards!"

Photos here

Update:

None of the cars have empty tanks, so if they were trying to steal petrol, they didn't succeed.
The damage came to R500 for the VWs, which isn't bad at all. (Replacing the lines would be a mission, my mechanic repaired them). Excluding many hours of towing, phone calls, e-mail, and SMSs, though.

LRL2007 Roundup

Stefano Rivera — Tue, 10 Jul 2007 10:16:23 GMT

Lugradio live is now finished and done. It was well worth attending - I really enjoyed it. Wolverhampton is a shit hole of note, but the conference itself was good.

Notable talks I saw were:

Malcolm Yates from Canonical: numerous talk on anything that he considered relevant :-)
Alan Cox on how to help in Open Source, and persuading hardware vendors to part with their documentation.
Matthew Garrett on Power Management
Scott James Remnant on 10 really cool things (quite a few of which didn't work) :-)
Michael Sparks from the BBC on Kamelia - a concurrent programming framework
Becky Hogge from the Open Rights Group
Gervase Markhams brilliant talk - How to Win every argument. He went through various fallacies, and how to use them to your advantage.
Joe Born from Neuros

Talks that I missed, but want to catch up when they post the videos (any guesses why I'm blogging this :-)

Flumotion
IAAL (I am a lawyer)
Telepathy
Gong a Thong
Chris diBona
ELER

I walked off with a free Nokia N800, as I'd come from so far away. A man who flew in from Singapore also won one. I have a suspicion that the Californians should have got it instead of me, but the WiFi was down so nobody could google distances :-)

On that topic, I really think that all geeky events like this should have pervasive WiFi coverage. Some of us are a long way away from home, and would like to be able to read our mail in-between talks. Also, it makes the GPG key signing party easier. I didn't pre-register for the signing, so only a couple of people signed my key, but I did get 2 CAcert assurances. I'll try and get some more points while I'm in a part of the world, where you can actually find assurers.

The N800 is very cool. It's ARM based, runs Linux (Maemo), and has decent WiFi / bluetooth abilities. If you want to quickly check your mail, watch youtube (yes it has flash) or do some basic IRC chatting in free wifi zone (i.e. a hotel reception area), then it rocks. The handwriting recognition isn't great, and it's quite different to what I'm used to on my P910. So I mostly use the on-screen keyboards (there is quite a good thumb-sized-keyboard option).

It uses Telepathy for Jabber IM, and has a few VoIP options: Gizmo, Skype, Google Talk. But the best part is that because it's an open platform, you can run most Linux software on it. I've installed Xchat, Mplayer, and an Xterm, so far... Because my amd64 laptop can't run Skype / flash, this is a really handy device to have around.

My train back was re-routed, and in total, it took 5hrs to get home :-( (fortunately I had a movie to watch on the n800)

LRL 2007

Stefano Rivera — Sat, 07 Jul 2007 08:56:10 GMT

For those who don't know, I'm in the UK, catching up on some sun and geeky events. The sun hasn't got going yet (I still have my South African cold), but I'm in Wolverhampton for LugRadio Live 2007.

Getting to Wolverhampton was a pain in the arse:

My credit card got replaced last week, but the new one has a PIN number that I don't know :-)
I missed my train because of the above, and had to wait until after rush hour.
Then ended up catching a train to Manchester by mistake (I'm a geek, I only read signs once, and expect to be going the right way)
So an extra hour's detour later, I was in Wolverhampton, but my taxi got stoned by teenagers hanging outside the Kebab joint.

Anyway, now I'm sitting outside the cafe at LRL, and occasionally posting photographs

The poor cafe's internet connection is screwed - the DNS totally broken, OpenDNS is the answer: 208.67.222.222 Mr Butler from Ubuntu UK plied me with Biltong and free "Powered By Ubuntu" stickers. Wohoo!

Chip and Pin Woes

Stefano Rivera — Mon, 14 May 2007 18:41:00 GMT

I have the pleasure of having a UK money in a bank account and credit card. This is great, because UK cards are the only ones that don't charge exorbitant currency-conversion charges when you use them overseas. I live in Cape Town, so I'm almost always using it overseas.

Chip and Pin, never used to be supported on South African credit card equipment, but these days, it's mandatory in UK, and supported on almost all credit card machines. Back when it wasn't supported people just used to swipe the card. Now, they actually try and read the chip. The procedure is something like this:

"Ready"
"Insert card"
"Swipe card"
"Insert card"
etc.

At some point, they give up, and ask for another card. The good ones can go between swiping and poking in a fraction of a second, in the belief that the faster they do it, the more likely it is to work. The only real solution seems to be to get the supervisor card out, and override Chip mode....

I thought that was all, until yesterday, when I got an even more interesting error message: "The PAN length does not comply with the min/max length in the BIN file". Does anyone know WTF that means??? :-)

4 days on the Orange River

Stefano Rivera — Mon, 23 Apr 2007 17:32:47 GMT

I've just got back from a week away, rafting down the Orange river. (Yes it was term time at UCT, I bunked classes :-) )

We went with Gravity, on the recommendation of my sister, who is an ex-guide. If you want to not be going with strangers, you need numbers, so we got a group of friends together, and my brother came down from London especially for it.

It isn't the cheapest way to spend a week (1200kms of petrol and ZAR 2k for the trip), but it was well worth it. Gravity specialise in the Orange river Gorge, and don't have a permanent base on the Richtersveld section of the river, which we requested to do. But they hired a local camp site, and brought the equipment down for us. Our guide, Ant, was very experienced, a good river-cook, and generally good fun. He even persuaded a friend of his, who was about to go home on leave, to come down with us, as a hard-working assistant, "on holiday". The food they produced for us was, while made from simple ingredients, phenomenal. There was always too much, and we had a cooler-box per day for us to bring our own cold beer (and other drinks). The ice just lasted to keep everything cold for 4 days.

The scenery in the Richtersveld is spectacular. The river is a strip of incredibly fertile land, down the middle of a barren desert. You are surrounded by a mountain range of loose, rocky mountains, brimming with Quartz seams. While it feels like the middle of nowhere, there are goats, fisherman, and mining activity around, which is a pity -- when I've been there in the past, it was far more barren. Fortunately, there was no (South African) cell phone reception, and my laptop stayed at home. :-)

I took quite a few photographs (in-between rapids, when my camera had to be packed away in a waterproof container). I didn't expect it's battery to last for the whole trip, but it did, which was great as I don't have a spare :-). Taking panoramas seems to be all the rage these days, so I took quite a few, but I haven't managed to stitch them together yet...

The river is of course the border between South Africa and Namibia, so on our way, we had to go through the border, get stamped into Namibia, then come back (without getting stamped), and go to our base camp on the South African side (while officially being in Nambia). Then, at the end of the trip, we got picked up from the Namibian side and driven back through the border (getting stamped this time). Fortunately, once you get away from the border post and onto the river, no one cares about borders any more :-)

The day is phenomenally hot (even in this calm time of the year), and so you constantly jump into the water for a swim. Or find someone who you can splash, so that you can start a water fight, and end up soaked :-)

There was quite a bit of paddling to do every day (as the water was low), but it was quite relaxing, and not very stressful. We even had a tail wind one day, and could put up kekoi sails. All in all, we covered 75km in 4 days.

The nights weren't too cold (thank god, because I forgot my sleeping bag, and had to borrow a rather thin one from the Felix Unite camp), but clear and dew & mosquito-free. It was new moon, and the stars every night were spectacularly bright and plentiful -- I wish I'd taken a star-map with me.

All in all, I highly recommend that everyone do this trip. Gravity are great, and our guide, Ant, is worth requesting :-)