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Power delivery

2010-08-04T16:20:00.001+01:00

Power delivery, originally uploaded by pjvenda.

The final link between drive train and rear wheel.

St Michael's mount

2010-07-20T19:20:00.001+01:00

St Michael's mount, originally uploaded by pjvenda.

The narrow twisty footpath into the castle.

Spotify maturing as a business?

2010-07-15T23:12:00.002+01:00

Spotify is a great product, I use it every day. It's an online music streaming service available for a number of countries in Europe (sorry, Portugal is not in the list yet... shame on you Spotify).

Warning: This is my own opinion... a long one.

I have been using it since its early days, when signing up was open and free and their ads seemed "amateur" at most. They even had a "Spotify voice mail" into which users left their messages of spotify-glory eventually ending up in self-advertising ads.

Discussions with business aware people led me to believe that there is something not quite right with their business model. To users it was music on tap for free, high quality, high availability, nagging ads but nothing we couldn't live with. I know that the key of success in online services is the ability to create a critical mass of users. Hence it made sense to give away music on tap for free.

Starting a business is difficult and incurs a lot of risk. Most technology companies have significant losses during the first years of operation, but often after braking even, the gains far outweigh the losses. In other words, losses in this case == investment.

But this is not sustainable forever and something was bound to happen. They would have to change the revenue model or increase the density of ads (a lot!) in the free accounts to make people switch to the paid version or go bust or be backed up by a company that made money some other way...

Adding to this, they implemented some serious anti-tampering stuff into their windows client since the very initial versions, including fancy anti-debugging and obfuscation code. Clearly they either over-engineered it or just prepared for a longer-term reality... Not that it is a bad thing, implementing decent security measures since day one, but it was also a visible sign that they did not want people cracking it.

The way I see it, there's a thin line between giving away enough to attract interest and new users and charging enough (from whatever multiple sources) to keep the business afloat, or at least following to the almighty business plan. Giving away stuff keeps people happy and attracts new users, etc, but does not pay the bills. Shutting the service to paid customers would kill the expansion of their user base. I think they never got this balance exactly right (assuming of course it was possible in the first place).

Over the past year or so they introduced various changes that affect the afore-mentioned balance. Their initial model was something like:

Paid ads;
Free accounts to everyone: Lots of music available, ads that could not be skipped;
Premium accounts for £9.99 per month: No ads, higher quality streaming;

Shortly after the following features also appeared:

Paid ads: Arbitrary companies were able to advertise in Spotify, spamming free accounts forever. Artists were also advertising their work via Spotify ads;
Premium accounts: Offline mode, mobile access for some smartphone platforms and unrestricted international access, even higher quality streaming, invites were provided;
Free accounts I: access out of allowed countries was limited to 14 days, [the mac client paused ads if sound was muted - sneaky, eh?];
Mobile access: Various applications were created and deployed for the most widely used smartphone platforms (iPhone, android, any other?). This is, of course, restricted to premium accounts;
Free accounts II: All existing free accounts kept working normally. However, free accounts could no longer be created without an invite. Invites were being handed to paying users and could be used as tokens to create new free accounts. So free accounts stopped being free, essentially;

Now the free user base could only expand with the help of the paying user base. Clever! The number of invites given to premium account holders was now controlling expansion of the free user base. So if you didn't have an account, you'd be left with 2 choices: either find someone with a premium account and get an invite from them or buy a premium account yourself.

Also there was little choice to the user base. Either you have a free account with nagging ads or you pay £9.99 per month... or the ridiculous £9.99 for one day. There weren't too many commercial ads, most were artists promoting their music/albums/singles/whatever and the rest were self-advertising. Targeted ads seem to work so-so. Some ads my wife gets I never heard and vice-versa. However, I still get spammed by Rhianna's promotions... something's very wrong there... My playlists are little more than Iron Maiden, Bruce Dickinson, Megadeth, Manowar... you get the picture...

Fast forward to 2010 Q1/Q2 (IIRC) and here's some more changes. I think these prove what I described above. Spotify decided to press on and attempt to expand its paying user base now. This was expected, and as far as I'm concerned, overdue by now. What we have now is:

Paid ads: Arbitrary companies were able to advertise in Spotify, spamming free accounts forever. Artists were also advertising their work via Spotify ads;
Free accounts: Left untouched. All free accounts are kept working, but can only be created with an invite coming from a premium account;
Premium accounts: Mobile access for some smartphone platforms and unrestricted international access, even higher quality streaming;
Integration with locally stored music files: The Spotify player can now play locally stored files and even share them with mobile clients. I don't know exactly how and when this works, but it sounds 'local'. Nonetheless, it makes sense to me;
Open accounts: Free version of Spotify, no invite necessary, but limited to 20h per month. Like a demo, really;
Unlimited accounts: Poor man's premium account. Half the price of a premium account but no mobile access, no offline mode and no streaming abroad. Pretty much all the good features gone except for the music, of course, and with no ads;

There it is, another shift towards expanding their paying user base. This starts to open up the choice range of non-paying customers and the game just might start changing. I'm not yet willing to invest £60 per year on a Spotify Unlimited account (the premium is still too much), particularly because most a lot of the music I enjoy is not there (which I reckon is mostly my own problem). However, it begins to become more and more reasonable to a wider and wider range of users and potential users.

I must also say that my ramblings about expensive and cheap are, of course, relative. What's expensive for me may be very cheap for you and vice-versa.

Good stuff, Spotify! Now get those label contracts going (get Rammstein back on the lists please, btw), as well as Metallica, AC/DC and every other song in the world :] A bit like Google! Hmm.....

Capelinhos

2010-07-14T12:12:00.001+01:00

Capelinhos, originally uploaded by pjvenda.

A massive eruption took place in the sea just meters in front of this lighthouse in 1957 (over 13 months). What was before the tip of the island is no more. This is now a magical place of inevitable history and volcanic science.

Once liquid I

2010-06-24T19:16:00.001+01:00

Once liquid I, originally uploaded by pjvenda.

The more I look at this picture the more I like it.

And it's not one of those I thought: "this will make a fantastic shot" when I took it.

Fly Azores

2010-06-15T11:53:00.001+01:00

Fly Azores, originally uploaded by pjvenda.

Shot minutes before boarding.

Twisty

2010-05-13T13:47:00.001+01:00

Twisty, originally uploaded by pjvenda.

Hydraulic vs bucket+shim valve adjusters

2010-05-08T00:28:00.004+01:00

Been researching the various valvetrain designs out of a philosophical discussion on hydraulic adjusters not commonly employed in motorcycles (H-D engines are the notable exception). Fascinating!

I found out how hydraulic adjusters are currently used in various car engines and how elegantly they solve the problem of keeping valve clearances. I also read a bit about pneumatic actuated valves with cams/followers or with electro-hydraulic actuators and no cams. Clever!

Being uninformed about hydraulic valve adjusters, I did the right thing and researched a bit. I'll share a summary for those that, like me, would like to know.

Hydraulic valve adjusters are a clever solution meant to solve the problem of keeping correct valve tolerances at any engine/oil temperature. Incidentally the design led to having permanent contact between cam, lifter, pushrod, rocker arm and valve stem, making it quieter.

[I now realise that the more common cam followers+shims+buckets should equally have (more or less) permanent contact between all the parts. This happens because followers to shim clearances are filled by oil pressure that builds up underneath the buckets as the engine runs: makes sense and came from a very reliable source.]

This is an open loop feedback system in which pushrod operating travel changes by action of hydraulic lifters which, in turn, are influenced by engine pressure and/or temperature. Ingenious!

"Our" design is more on the style of "getting it right for the typical range of engine temperatures".

Two typical engineering approaches to the problem, both with their pros and cons. While it's easier to see the cons in the non-hydraulic shim+bucket style system, the hydraulic type is not without them:

Being an open loop system, it relies on correct information coming in from oil (density+type+dirt+volume=different pressure vs temperature curves) as well as integrity of the lifter itself (spring load). But even if everything else is kept, oil changes with wear and that affects operation of the lifters. Self adjusting valves gradually come out of adjustment at all engine temperatures. Then of course this is a more complex system and probably more expensive to manufacture. Hydraulic lifters are precision parts with very tight tolerances. It is hard to tell if the time it takes to get a valve significantly out of tolerance is so long that it becomes non-serviceable... I really don't know. Some people say yay other say nay.

Me, I would go for the hydraulic type, but I'm an engineer, not a business man. On that note, how about the desmodronic valve actuator system currently used in Ducati engines? Funky, eh?

Thanks for reading. Feel free to poke holes at it.

References were:

http://dansmc.com/valveclearence.htm
http://www.samarins.com/glossary/dohc.html
http://scarbsf1.com/valves.html (nice other resources on this site)
http://en.wikipedia.org/wiki/Overhead_camshaft (nice cutoff pic of bucket+shim valve arrangement)
http://en.wikipedia.org/wiki/Hydraulic_tappet
http://www.ratwell.com/technical/HydraulicLifters.html#operation
http://www.animatedpiston.com/BMW.htm
http://www.seastarsuperbikes.co.uk/ducatiengines.html

The long way home

2010-05-03T00:43:00.008+01:00

One wonderful thing about bikes is that much more often than in a car, you go out for a ride with no purpose, sometimes with no defined direction or destination.

I work in an office in Thame, roughly 15 miles away from home. Commuting by motorcycle is good and fun: not too long, very little traffic, twisty but safe (good visibility throughout, no sudden tight bends, etc). It's a good mix of city, dual carriageway (A40) and A-road (A418).

View Larger Map

As the weather improves, the sun now shines past 7.30pm (sunrise, sunset, dawn and dusk times), it's time for some road exploration / wandering on my Triumph (I really should have blogged about my new speedmaster by now...)!

I prepared a route based on something I tried before and set off from the office after work with a memorised list of road names and a few visual cues taken from google street view. Although I didn't follow the plan entirely, the result was the route below:

View Larger Map

"The long way home" is the name I gave to the 50 mile route (above) out of Thame around the south of Oxfordshire and back into Oxford via the Donnigton bridge / Iffley road.

Highlights:

B4009 from the A4074 turnoff to Goring-on-Thames: Superb scenic twisty road with a few villages here and there but without breaking the rhythm too much;
A417 from Goring-on-Thames to Blewbury: Another very scenic twisty road with a number of hills and less villages than the B4009 (IIRC);

Great bits of road, but not quite highlights:

B4009 from Thame to Benson;
B4016 from Blewbury to Didcot: very twisty, most bends are blind. not too many chances to overtake;

Ideas, alternatives, improvements:

Avoid Didcot ring road by following the A417 a bit further and then turning off to the A4130 at Rowstock;
Try the B4009 further than Goring-on-Thames, perhaps even all the way to Newbury;
Keep on the A417 until Wantage, then A338 up to Wootton or join the A420 and back to Oxford;

I managed to discover/execute this alternative route home which included some of the best bits of road I've ridden so far (mind you my experience is limited). This was a fantastic ride that I look forward to do again soon.

(feel free to share if you know any great roads around Oxfordshire)

Until next time,
Pedro.

lame sysadmin

2010-01-10T17:03:00.013Z

Weird stuff went on recently on my network;

It started last night while I was fiddling with my lab network - dark witchcraft including ospf, eigrp, nat, acls, ppp/chap, etc. I discarded it as being my laptop still fussing with its gateways and default routes... I was tired and didn't care. So I just turned things off, went to bed and forgot about it.

[side note: I should post my network diagram someday, so everyone can appreciate a true overkill geek home network...]

Cisco home and lab networks, originally uploaded by pjvenda.

This morning, though, my wife couldn't reach facebook from her laptop. Whoops, I must have done *something*...

Symptoms were:

able to ping external hosts;
unable to access websites;

First things first: Check the squid proxy - seemed ok;

Lazy as I am, I decided to just reboot the routers because I might have left some not-very-well-though-configs there. The routers came back up and the situation got worse! Now I had no comms between the core and uplink routers. WTF?

Moral of the story #1: Having bpduguard on switch ports that link to routers is not necessarily safe.

The router was broadcasting BPDUs out its ports triggering bpduguard on the switch which, in turn, disabled all the ports that connect to the router (the ones from which BPDUs were received). This effectively shut the router off the switch.

As a quick & dirty solution, I enabled bpdufilter on those switch ports. Just ignore those BPDUs instead of disabling the ports if one is received (bpduguard is setup globally on the switch, rather than port by port); The proper solution involves shutting down STP on the router instead with no spanning-tree vlan X commands.

Layer 2 issues sorted, I was back to last night's situation. Being a little more pragmatic this time, I disabled wccp redirects from the core router. Sure enough, everything was back to normal. The proxy was good but the connection between the core router and the proxy service/host was not (this connection being a GRE tunnel - did I mention how nice WCCP is??).

Moral of the story #2: Be pragmatic, not lazy.

I had a massive update pending on the server including a kernel upgrade. I had to reboot now. Naturally the server did not come back up as expected because the updated version of udev required a kernel >=2.6.27. The latest accessible kernel was 2.6.26 - d'ough!!

So there I was manually creating md nodes on /dev via a serial console to mount and copy the newest available kernel, modify grub's configuration and try again with a new kernel. It worked! Everything came back to normal, the GRE tunnel came back up, as all other services on the server.

Moral of the story #3: Don't slack on your sysadmin duties, update often and check that things are still working after updating. Make sure you reboot from time to time to verify that everything is starting up nicely.

Along with all this, I forgot about the new terms of service of editdns.net (my DNS provider) and they cancelled my account. My domain pjvenda.net has been unavailable since 3rd January 2010 and should only be restored after tonight (10th January 2010).

Moral of the story #4: Make sure you have a working DNS service for your domains. Otherwise they don't work.

I'm lame sometimes. Must be the cold.

Cheers, PJ

Photographic record of the last ride of 2009

2009-12-13T20:45:00.000Z

I know there is still time, but I don't expect many more convenient breaks in this British weather.

I took this picture after coming back from a short ride earlier this month - an English December, mind you. It was a good ride through Oxford city streets. The weather was dry and not too cold (for my kit). If everything seems grey and dull, it's because it was.

I doubt I'll be able to go out again this year and if so, here it is: the record of the last ride of 2009.

Cheers, PJ.

Night lights at the Colosseum

2009-11-09T14:29:00.001Z

Night lights at the Colosseum, originally uploaded by pjvenda.

Taken from the hotel's balcony, while having dinner, during my honeymoon.

The balcony shook as every tram or bus passed by, but the result was not bad. 30sec exposure done with an EOS 350D + Sigma 18-125mm.

Posted one day after I signed up for a flickr Pro account.

Back to base

2009-10-13T11:31:00.003+01:00

Back to base, originally uploaded by pjvenda.

At Farnborough 2008.

Elevator shaft

2009-09-10T20:52:00.002+01:00

Elevator shaft, originally uploaded by pjvenda.

Going up?

CSS is magic

2009-09-06T14:11:00.001+01:00

90% of the effort required to change this:

into this:

(which is awfully similar to this:)

was invested on a Cascade Style Sheet.
HTML+CSS can be about as good as LaTeX.

Hi-Tech

2009-09-05T17:43:00.003+01:00

Hi-Tech, originally uploaded by pjvenda.

Moto Guzzi Griso 8V. A clever looking pure italian bike.

This is the first post in a "photo blog" style that I may start to introduce on this blog as well.

Cheers, PJ.

Lead-acid battery maintenance and diagnostics: What I have been doing

2009-09-04T08:47:00.002+01:00

The stuff you learn as you go along ...
... needs to be shared with those that might not know yet.

When my Virago would not start two weekends ago, I and my friend jump-started it off his own bike. Once warm it would start again normally, so we set off for a 120 mile ride and I attributed the problem to myself: "I just flooded it when I first pushed "start" but now the alternator should get things in place again..." But that did not happen. Since then the bike did not start again without help, that is. It only fired up again with the help of the car's battery. I could jump-start it from the car, go for my ride and hope that it would start again (while warm).

Troubleshooting begins:

Starter cranks the engine a bit (half-turns), neutral light fades while it happens
The headlamp still works with the bike off

Seems obvious - it's a weak or half-dead battery.

Immediately I ordered a fancy charger (yes, it's blue! but in my defense, it was not my choice) to check and charge the battery, which failed miserably because it has not been delivered yet... Seems to be out of stock everywhere, I should have known better... Well, before the charger comes in, I figured I would do what I could to get more information out of the situation.

The exact model of the battery is Yuasa Yumicron YB12AL-A2. It's a lead-antimony type 12V 12Ah motorcycle battery. Yuasa kindly provide this very insightful document in their website summarising the technologies behind their ranges of batteries and how they fit into different types of requirements.

Before even taking it out, I noticed that no fluid could be seen around the MAX or MIN levels. Either because the plastic was too opaque or because the level was not even close to those levels. Next thing was measuring voltage levels in different situations: no load, loaded but engine not running, engine running. Results were approximately:

Unloaded: ~13V
Loaded: N/A (didn't measure)
Running at idle: ~18V
Running over idle, unloaded: ~17V

Aside from potential regulator/rectifier issues, I saw nothing particularly alarming here. So I took the battery out to have a good look at it. This visual inspection revealed the following:

All connectors and metallic contacts were in very good condition - no corrosion or grime even
The battery itself was clean and looks recent
There was no fluid whatsoever inside it. It was completely dry

All sorts of trouble may arise from semi-dry batteries, including quicker corrosion of internal and external materials due to increased acid concentration and electrical properties must change as well - from internal resistance, maximum current output, voltages, etc - nothing tolerable in the medium/long term.

What I cannot understand is how a completely dry battery could conduct *any* current, as it did. I would expect a battery to fail gradually before being completely dry which was not the case. A bit of misleading research led me to believe that this particular model of battery soaked the fluid (into some material) which would explain why it would not drip... True or false I don't know yet, as I could not find that information again. Oh, and there is also the little detail about: "Is the dry battery a cause or a symptom?" - I do not know yet.

If the battery was dead I would need to replace it. But it could also be brought back to life by filling it with de-ionised water and recharging. Having nothing to loose, I bought one liter of de-ionised water and (carefully) poured it in. [bloody filling holes must be made to be filled with seringes!!]

Immediately I measured a drop in voltage of about 1V. Back on the bike, I re-measured its voltage just to double-check that things were OK. Turned it on, re-checked things quickly, hit START and it fired-up promptly! Once more I measured voltages with the engine off and on, empty and loaded (lights on).

Unloaded: ~12.1V
Loaded: ~11.75V
Running at idle, unloaded: ~17V
Running at idle, loaded: ~13.5V (~15.5V when a little warmer, may go up a bit more)
Running over idle, loaded or unloaded: ~16.5V

With the engine running, the electrical system should be mostly (or totally) powered by the alternator (stator/generator) through the regulator/rectifier, while at the same time recharging the battery for the next start-up (voltage at battery terminals should be >12V). This makes sense and my measurements are consistent. However, three things are still concerning me:

Loaded voltage is slightly below 12V and seems to drop quickly
Power coming from the charging system may have a higher than normal voltage (~17V)
According to manufacturer specs, 12.1V of unloaded voltage is equivalent to about 50% of charge

Best case scenario:

Battery is still good just needs maintenance. The least of my worries is buying a new battery.

Worst case scenario

Either the stator/generator or the regulator/rectifier (or both) systems are frying the battery. Not nice as the following might have to be replaced:

While at it, why not read a bit more about the whole charging system. Knowledge is power.

Bye for now.

Home network / Cisco testing lab

2009-08-24T13:21:00.005+01:00

[1]: "Dog's bollox' syndrome", autistic geekiness, paranoid overkill network admin, will to learn. Call it what you like, I don't care.

This is about my home network. I've been getting my hands on some Cisco kit because it has always been a technology I wanted to learn about. After gathering a few newer or older devices, I was able to re-do my home network, with separated user, management, service and DMZ networks - done with the good help of ACLs, NATting and inter-VLAN routing. Internal services are explicitly accessible or transparently proxied, external service are NATted into the DMZ network. I am even setting up a direct Internet access network as fall back. Most of this stuff is provided over Wired Ethernet and 802.11g Wireless. Why? See [1] (top of post).

It all looks like this at the moment:

Cisco home network

At the moment, the following devices compose and actively participate in this horrible wire mesh that I call "home network":

Cisco Catalyst 3548XL: 48 10/100Mbps Ethernet port core switch;
Cisco 2621XM: Core/Internal router and firewall;
Cisco Aironet 1231G: Wireless access point;
Cisco 877W: External router and firewall with DSL modem and wireless interface;
Linux server: (not seen in the picture) Provides storage and other network services such as SMB, authoritative and cache DNS, HTTP proxy, etc; There is a web page about this box on my website: Home server;

Because I am still a Cisco "newb", I needed to learn about the features that I needed as I went along. Stuff like configuring native and tagged VLANs with trunks on the switch, multiple networks on the access points (each going to a different LAN segment), setting up static routing, ACLs and NATting, enabling and using an ADSL cisco interface, managing Cisco IOS images and configurations, etc. It starts making a lot of sense as all the pieces of the jigsaw find their place in my mind, but it seemed a bit strange when I started.

I know for a fact (because I have seen them) that certain company setups are light-years away of mine both in size and in complexity. What is funny is that certain cases are light-years more complex but others are light-years simpler (d'ough!).

I quickly learnt that a network like this requires absolutely the permanent presence of an up-to-date network diagram and detailed notes with IP addresses and ranges, interface names, VLAN to IP mappings on the various devices, VLAN and trunk mappings on the switch.

[A random network diagram I ripped off the Internet for illustration purposes only. Mine is hand-written.]

I also learnt that Cisco is a huge corporation in such a good market position that allows charging of hefty sums for hardware and licensing together with software limitations on their devices (dependent on licensing levels). This is not easy for me to swallow. But I must say that their documentation is terrific in every aspect! In particular the following guides are absolutely top-notch in content and references:

There are many more great Cisco guides that should be on the list above, but it would just group exponentially. And I am not even thinking about Cisco Press paper books.

Apart from being an over-zealous sysadmin, I am also a bit paranoid with security. So I will not be giving away details about configurations :]. At least not at the moment.

Following the logical steps, I should be taking a CCNA exam in the near future...

Cheers, PJ.

Website is back with a few changes

2009-07-21T10:08:00.013+01:00

After about a month offline, I managed to bring my website back. It's now hosted in Canada attached to a nice big 100Mbit/s network pipe.

It's also been slightly updated with a nice little flickr photo of my collection shown in every page.

Other changes include a new domain registrar, DNS system and domain name to which my stuff will slowly be ported to. I will maintain the old domain indefinitely but things should redirect to the new one. So have a look:

`http://www.pjvenda.net`

This blog is now accessed at http://blog.pjvenda.net. The old address transparently redirects here, so no worries. I plan on integrating it with the website but that may take a while.

See you later!
Cheers, PJ.

Website is down

2009-06-30T11:31:00.002+01:00

My website is down. Sorry for that. I'm moving and at the moment about everything that I own is packed in a non-useable dining room. Including the server with my website.

I need to sort out some DSL service, pull a phone extension and plug things back to get the website back up. Should take a few days, though...

So bear with me, I'll be back.

Cheers, PJ.

Test ride of a Sportster 883R

2009-05-18T11:53:00.001+01:00

Funny how I think of starting every post with an "I'm not dead" (like the old lady in the Quest for the Holy Grail...). But it's true, I'm not dead - I'm just not a good blogger, that's all.

Sure there are other news about me but the recent and cool one was that I test rode a Harley-Davidson Sportster 883R.

I took the oportunity of HD's marketing campaign "Judgement days" and signed up for a test ride of a Sportster 883 Iron. What I really wanted was to see how well I could handle its weight (the XL883 weights 251Kg whereas my XV535 weights 182Kg), how good was the riding position (me being 1.6m tall or 5"3'), and how strong was the Evolution 883cc engine.

So I got there, the guy literally asked: "so, which one do you want to try?" (which, I think, is something you don't get asked often...) and I signed the form that essentially said: "if you screw up, you're on your own. if you die, it's not our fault".

Then I was given the quick walkthrough over the controls etc and finally I was given the key: "get back within 45min. good luck and enjoy!". What a mixed feeling of "Ohhh boy!!" with "God, what am I doing?". I geared up, whilst mentally planning my route and pushed the starter. That was loud!

2008 Harley-Davidson Sportster 883R, originally uploaded by pjvenda.

The throttle was soft and smooth and very progressive, but with a much greater gap than mine, so it felt a tiny bit strange. The handlebars were WIDE and my standing position wasn't as good as on the XV535. Clutch and front brake levers are small but very smooth, so good stuff. The gear lever is well placed and very precise.

I set off and did two laps of the route below, which accounts for about 14 miles (~23Km) total. The route starts at the HD dealer from which I headed SE towards Abingdon, then left through Abingdon's "ring road", left again towards Oxford and left once more towards Wootton / Boars Hill through Fox lane and back to the HD dealer.

View Larger Map

Main impressions were:

My 535 engine must be incredibly ashmatic, bearing in mind the sportster's 883cc engine is notorious for its lack of power. What?? It felt like a brute!
The brakes were really nice and returned a good progressive feeling of stopping power;
The suspension is hard. There is no way around it. And that seat it must be great for vintage stuff, but not for me;
I couldn't flat-foot as I do so easily on my 535. The 883R is notably taller. On the other hand, while riding, I felt my knees even more bent than on mine, so the seat is higher, but the pegs are even higher;
The handle bars were WIIIDE, which felt good - mine are too bent inwards. But they I had to bend a little to be confortable with them, so I reckon they should be pulled back a bit for a guy of my height;

After the test ride, I was a bit deaf but very happy with the bike and the ride itself. It had been very good fun and I am enjoying the Sportster even more. I would gladly ride it for a whole day or weekend (which I eventually will). Now the real question is:

\begin{Jeremy Clarkson impersonation}

- Would I buy it?
...
- Nnno.

It is too loud, the handlebars are too far, the tank is too small and that seat is rubbish.

\end{Jeremy Clarkson impersonation}

I would happily buy a Sportster, though. And if the 883R was the only model, then yea, I would buy it. But it's not. First there's the Evolution 1200cc engine which is better at everything with the same weight (for some extra petrol, of course).

Harley-Davidson Sportster 1200 Low, originally uploaded by pjvenda.

This 1200 Low, I reckon, would solve my problems with ride height and handle bar location. Also, it has the bigger tank (four thumbs up!). On the low side, I'm not such a fan of all that chrome... I would very much prefer the look of the Nightster. I guess I'll have to settle for the cheaper then :)

Before you flame me out of the Internet, I know that, in general, the biker community has some strong feelings about Harleys. Harley riders love them to bits even though they can't always explain why with technical facts (which tend to be the kind that you don't argue with). Non Harley riders tend to generate a bit of a hatred towards "the others" and happily (and quickly) bash harley technology. The fact is that such exercises (whichever brand or style you take sides on) are futile. In the end, everyone rides what suits their style best, what they think looks better, what they can afford, etc.

I am not saying that your bike doesn't tell about your personality, of course it does. But what it doesn't tell is about your respect and attitude towards others.

All for now.
Cheers, PJ.

I am a biker now!

2009-03-11T16:15:00.004Z

Very quick post - only the news of the year!

Me and my Virago 535, originally uploaded by pjvenda.

More stuff soon - have to go for a ride now!

Cheers,
Pedro.

More next year

2008-12-28T22:50:00.001Z

I'm still lousy at this. But I'm taking a break from my stressful (?) blogging routine until sometime next month, in 2009.

Here's a short wish list of mine for next year:

* I would like to improve my photography technique. I would like to have a Canon EOS 5D mkII on my budget as well as a new tripod, at least two decent lenses and bibble 5 (which is proving to be a difficult birth). I will upload stuff to flickr.

* Some really exciting stuff is happening at the beginning of next year, which will be a worthy blog post when done. Until then, it's a surprise (even for me, to a certain level).

* I am also looking forward to book my leisure flight on a Cessna or a Piper somewhere in the UK - courtesy of my lovely wife. That will be amazing and bring me closer to aviation in a techie kind of way. A baloon ride would be excellent as well :)

* I will do a bit more of travelling around but that isn't well determined, yet. I know I'm going to Prague, but that's it so far.

* I *need* to do some go-Karting again as well as, perhaps, another track day experience.

* I should blog more often. I know that some of my friends read this sorry excuse of a blog so, it is in my best interest that they be informed of what's going on on this side of the channel that deserves being blogged about. But that's not always an easy task. Also my techie reviews and rants are sure to be useful for someone...

* I will update my website more often and, more importantly, with new interesting material. This includes interfacing with blogger and flickr.

So long. Back next year.
Until then: Cheers, PJ.

A visit to the Harley-Davidson dealer

2008-11-16T02:13:00.021Z

Hello everyone,

Yes, I succumbed to the insistent calling of this (un)holy place just 5 miles away from where I live.

Decisions, decisions, decisions, originally uploaded by pjvenda.

And I felt like a little kid, shopping for christmas, with an unlimited budget! Not that I had a budget or even the intention of buying anything, but the mere thought of possibly doing so in a couple years time, really messed with myself in a most unexpected way. I never thought that visiting a store could create such a warm and fuzzy felling.

It felt strangely familiar and strangely similar to the Hard Rock cafe franchise - the music and decoration, the staff's black "uniforms", etc.

There were so many bikes for sale - some seemed pretty rare by the looks of it and from the warning signs that said "please don't touch or sit". All those Sportsters, Softtails, Dynas, VSRCs... All those obscenely expensive extras: the chromed screamin'eagle exhausts, the black matte screamin'eagle exhausts, the classic open face helmets, the leather jackets, everything else-leather...

Of course I took the opportunity to snap a few shots. Not that the light was great. I mean, it was when I left home, but as the 10 minutes went by between my street and Wootton, the clouds came in...

But of all things, this was it:

2007 Harley Davidson Sporster XL 883, originally uploaded by pjvenda.

When I walk in there again to order my own Sporster, that will be something to remember - I'm sure of it!!

Cheers, PJ.

ACPI standards used for specificity

2008-07-28T19:26:00.001+01:00

Even though the title might seem silly at first, the simple fact that it is there as it is means that there is some explanation behind. So true.

The open standard ACPI was released in December 1996 by a joint collaboration of the main industry vendors. Its purpose was to provide a common interface for describing hardware bits and pieces that might vary from computer to computer. Just like a hardware description language (HDL).

All motherboards today have a bit of ACPI code in their BIOSes that provide the list of sub devices that they have available for use. These sub devices range from internal timers to fan controls or temperature sensors. This happens because all motherboards are different, in a way or another. Even the most common and basic functional components may need to be configured in a slightly different way between different manufacturers. So this ACPI code is rather raw and important for the lowest levels of the operating system. [we could fork this conversation into the subject of "operating systems: hardware or software?" but we shan't. this post has a different purpose, so let's get on with it].

This, of course, is described according to the ACPI open standard independently of which operating system will be executed. When looking at different operating systems, they have varying degrees of ACPI compliance and robustness. Some have good ACPI interpreter implementations and do things well. They may be able to resist ACPI coding errors and still keep working well. Others are dyslexic with regards to reading ACPI right and break. Break because they read wrong or because they can't handle errors.

So ACPI writers decided to start differentiating their code with conditional bits that refer to specific operating systems. Bits like

if (os==os_identifier_string) {
 do this;
} else {
 do something else;
}

OK, so we start to see some specificity on ACPI code regarding different operating systems. But that's fine as it is being done to avoid or to fix existing or potential problems. On the other hand, Microsoft's operating systems have much more attention on this matter due to two reaons:

Windows OSs are regarded as the world's (only) operating systems. Manufacturers and vendors tend to ignore all other operating systems on end users' hardware;
Windows has never been any good at handling ACPI code;

Here is where things start to go wrong regarding ACPI...

My first laptop, an Acer Travelmate 4001 WLMi, had a few quirks in its ACPI code that resulted in some issues [I can't remember what exactly]. Because hacking ACPI code is a nightmare, there was an easier way to handle the. You see, fixes for those quirks were already in place, in the ACPI code itself, but in one of those conditional zones for Windows 2000 and XP. Not for other OSs. Fortunately it is possible to tell the Linux Kernel to identify itself as "Microsoft Windows XP" when decoding/interpreting the ACPI table, so I was able to fetch those fixes and get on with things. Remember: no need to hack or change the code because the fixes were already there.
Hacking ACPI code is not a walk in the park. It's not easy to find, not easy to decode, not easy to read and not easy to write.

In effect, ACPI fixes are being coded specifically for Windows. Fixes that are likely to be relevant and safe for all other operating systems, but because of manufacturers' disregard for everything non-windows, "the others" are being left out.

The dirtiest minds might imagine that this is, in fact, a very subtle (and smart) way to undermine support for non-Windows operating systems. All that's necessary is to discreetly influence [i.e. pay] manufacturers to include differentiated code that breaks things on Linux, BSDs, Solaris, etc. Companies could use an open standard to break compatibilities and enforce monopolies. Coward stuff, eh?

Well... it appears to be happening. Exactly that. See the (adapted) quoted text below along with my comments in between. [The full story can be found here: http://ubuntu-virginia.ubuntuforums.org/showthread.php?t=869249]

Ryan:
I've heard a lot of people ask, "Who the hell is Foxconn", if you use a PC, there's a good chance you have one of their boards, even if it's branded as MSI or some other brand, if you use a Nintendo Wii, XBOX 360, or Playstation 3, Foxconn made that motherboard, this isn't some little dodgy hardware maker with no name that we can afford to be quiet about.
------------
I have disassembled my BIOS to have a look around, and while I won't post all the results here, I'll tell you what I did find.

They have several different tables, a group for Windws XP and Vista, a group for 2000, a group for NT, Me, 95, 98, etc. that just errors out, and one for LINUX.

The one for Linux points to a badly written table that does not correspond to the board's ACPI implementation, causing weird kernel errors, strange system freezing, no suspend or hibernate, and other problems, using my modifications below, I've gotten it down to just crashing on the next reboot after having suspended, the horrible thing about disassembling any program is that you have no commenting, so it's hard to tell which does what, but I'll be damned if I'm going to buy a copy of Vista just to get the crashing caused by Foxconn's BIOS to stop, I am not going to be terrorized.

(...)

Linux and FreeBSD do not work with this motherboard due to it's ACPI configuration, using a disassembler program, I have found that it detects Linux specifically and points it to bad DSDT tables, thereby corrupting it's hardware support, changing this and setting the system to override the BIOS ACPI DSDT tables with a customized version that passes the Windows versions to Linux gives Linux ACPI support stated on the box, I am complaining because I feel this violates an anti-trust provision in the Microsoft settlement, I further believe that Microsoft is giving Foxconn incentives to cripple their motherboards if you try to boot to a non-Windows OS.

The correspondence between Ryan (the techie that uncovered this stuff) and Foxconn support (manufacturer of the motherboard in question) follows. It's a bit edited for spacing reasons. This is fun!

Ryan:
ACPI issues, cannot reboot after having used suspend

Jul 22 08:37:53 ryan-pc kernel: ACPI: FACS 7FFBE000, 0040
Jul 22 08:37:53 ryan-pc kernel: ACPI: FACS 7FFBE000, 0040
Jul 22 08:37:53 ryan-pc kernel: ACPI: FACS 7FFBE000, 0040
Jul 22 08:37:53 ryan-pc kernel: ACPI: FACS 7FFBE000, 0040
Jul 22 08:37:53 ryan-pc kernel: ACPI Warning (tbutils-0217): Incorrect checksum in table [OEMB] - 70, should be 69 [20070126]

I get these messages in my system log at boot, I also fail to reboot after having used suspend in a session, it hangs and plays a continued beep on the PC speaker.

Foxconn support:
Do you get the same beep codes if you were to remove all RAM out and then turn the system ON again?

Ryan:
No, because then I wouldn't be able to boot into Linux, suspend to RAM, to get the ACPI failure, have syslogd pollute my /var/log/messages file with it, or read about it in my system log.

In particular, the number of quirks that the kernel has to use, and this invalid checksum are what has me nervous.

If you need me to attach the full contents of /var/log/messages, I can do so.

Foxconn support:
This board was never certified for Linux. It is only certified for Vista. See URL below. So please test under Vista. Does this issue also occured under Vista or Winxp?

http://www.foxconnchannel.com/product/Motherboards/certification.aspx

That was a nice start... So the board is only certified for Vista, but by the way, does it work well in XP?? Just by accident, you know... Because it should, I/they reckon.

Ryan:
The ACPI specs are there for a reason, and broken BIOS's like what is in this motherboard are the reason standard ACPI does not work, I've taken the liberty of filing the report in kernel.org, Red Hat, and Canonical's Ubuntu bug tracking systems, and posting the contents of my kernel error log on my blog, which is in the first several results if you Google search "Foxconn G33M" or "Foxconn G33M-s", "Foxconn Linux", etc, as well as prominently in other search formats, so hopefully this will save other people from a bad purchase, and hopefully kernel.org can work around your broken BIOS in 2.6.26, as I understand that kernel is more forgiving of poorly written BIOSes built for Windows.

I've already gotten several dozen hits on those pages, so you guys are only hurting yourselves in the long run, by using bad BIOS ROMs, as people like me are quite vocal when dealing with a bad product.

Spot on: The ACPI specs are there for a reason.

Foxconn support:
Making idle treats is not going to solve anything.

As already stated this model has not been certified under Linux nor supported.

As you are unhappy with the product- using a non-support operating system nor certified, please contact your reseller for a refund.

Ryan:
I've been debugging your AMI BIOS, and the ACPI support on it is far from within compliance with the standards, I've dumped out the debugging data into Canonical's Launchpad bug tracking system so that we may be able to support some sort of a workaround for the bad ACPI tables in your BIOS, I would hope that you will be part of the solution instead of the problem, alienating customers and telling them to go buy a copy of Windows Vista is not service, your product claims to be ACPI compliant and is not, therefore you are falsely advertising it with features it isn't capable of.

I would ask that you issue an update that doesn't make it dependent upon Windows Hardware Error Architecture, but that decision is up to you.

Please find all relevant data here:

Bug #251338 in Ubuntu: “Bad ACPI support on Foxconn G33M/G33M-S motherboards with AMI BIOS”
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/251338

I appreciate your consideration in this matter.

Foxconn support:
You are incorrect in that the motherboard is not ACPI complaint. If it were not, then it would not have received Microsoft Certification for WHQL.

Refer to: http://winqual.microsoft.com/HCL/ProductDetails.aspx?m=v&g=s&cid=105&sv=&f=&pn=G33M-S&oid=3179

As already stated, this model has not been certified under Linux nor supported.

It has been marketed as a Microsoft Certified Motherboard for their operating systems.

Of course threats don't solve anything. But saying that "this product is ACPI compliant because otherwise MS wouldn't have granted us the WHQL stamp" doesn't either. And they don't seem very willing to try anything else... So I guess the threat was still the only thing that caught Foxconn's support attention... even though it was promptly dismissed.

Ryan:
I've found separate DSDT tables that the BIOS hands to Linux specifically, changing it to point to the DSDT tables Vista gets fixes all Linux issues with this board.

So while I accept that you've gotten some kind of Microsoft Certification (doesn't surprise me), that does not make your board ACPI capable, just that Windows is better at coping with glitches custom tailored to it, for this purpose.

Foxconn support:
Stop sending us these!!!

Yes, go away!

Ryan:
Your BIOS is actually pretty shoddy, I've taken the liberty of posting everything that's wrong with the DSDT lookup tables and how to fix some of it so the community that has already purchased your filth can make do with it, also, it's now pretty much impossible to google Foxconn and Linux in the same sentence without getting hit by the truth, that your boards aren't good enough to handle it.

Foxconn support:
Surely this is the way to ask for us to attempt to fix something that is not supported in the first place.

Ryan:
Would it be so difficult? I mean really? I suppose you've never heard of building a happy customer base vs. just angering everyone that deals with your products to the point they make sure others don't make the mistake of buying them.

You know, I have several computers, and they all support any OS I want to put there, as well they should, if you can't fix the damaged BIOS you put there intentionally, can you at least put a big thing on the site that says no LInux support so people won't make the mistake of buying your stuff?

Your DSDT table looks like it was written by a first year computer science student, it is scary, I will not just shut up and go away until I feel like I've been done right, this can end up on Digg, Slashdot, filed with the FTC that you are passing bad ACPI data on to Linux specifically.

I saw you targeting Linux with an intentionally broken ACPI table, you also have one for NT and ME, a separate one for newer NT variants like 2000, XP, Vista, and 2003/2008 Server, I'm sure that if you actually wrote to Intel ACPI specs instead of whatever quirks you can get away with for 8 versions of Windows and then go to the trouble of giving a botched table to Linux (How much *is* Microsoft paying you?) it would end up working a lot better, but I have this idea you don't want it to.

While I don't agree with the way that Ryan addressed Foxconn support in all occations, he does have a rock-solid point. He has the right to be pissed and they were replying as (not very good) corporate robots, so deserve some angry kicks. If their policy was in fact "not supported - won't fix" than they would not react in such increasingly defensive way.

He was lucky to get enough attention to actually get them to act and try to fix things. No promises of official BIOS updates and no reports of working fixes, but they did do something. Of course they did/do/will deny any explicit attempt to break things on the Linux side. But I don't believe them. It's just too obvious to be accidental.

It takes someone with skills and will to figure these things out. A very small minority of all computer users. And that's exactly why this is actually a good subversive way to subtly improve Microsoft's monopoly. Indeed with the help of the ACPI open standard, corporations are breaking compatibility by introducing specificity in the code.

Sorry for the long rant, but this kind of stuff ticks me off! People that know me know it's true.

Thanks for reading,
PJ.