Category — General Commentary

Following Tom’s suggestion, I’ve added the Subscribe to Comments plug-in so you can be e-mailed when someone responds to your comments.  If you have problems with this feature, please add a comment here.

I’ve also added a page to provide a central place listing posts with on-going discussions.  I’m considering adding some posts just for discussion; for example, I could add a new post just for discussing air bearings.

In the not too distant future, I will look at further improving feedback options.  I do not like options that require casual visitors to register, either to comment or with a third party site such as Facebook or LinkedIn.

I’m also not a big forum fan — about the only forum software I liked was the old pre-2000 InfoWord Electric forums.  In general, I think most forum software does not promote good discussions.  On the other hand, I’ve seen mailing lists work very well.

I think wikis are excellent for some types of information, such as structured reference content (the air bearing discussion is a good candidate).  That’s why I added a trac server to this site — but it needs upgrading.

As always, I’m open to suggestions.

So I’ve finally reached 50 published posts, at a rate of about a post every 10 ten days – not bad, considering how busy I’ve been.

I’ve made a small site change – my trac and subversion sites are now on http, not on https.  Https wasn’t really necessary, and as I plan on making better use of these sites I decided the hassles of secure sites weren’t really worth it.

I’m still going to stay off politics, but it does amaze me that many (most?) people are perplexed by the current financial crisis.  Although the exact details couldn’t be predicted, the fact that the US had a housing bubble in 2004 was obvious to anyone who looked clearly at the facts (house prices were going up faster than the fundamentals, e.g. medium house price versus medium income, house price versus rent, etc).  It was also obvious that many of the loans (e.g. Interest Only, Neg-Am, Option-ARM) were never going to be repaid, as they relied on house prices increasing.

Anyone who has lived in Silicon Valley since 1998 definitely has no excuse for getting caught up in the housing bubble after seeing the rise, the hype ("it’s the new dot-com economy and the old rules don’t apply"), and fall of the dot-bomb bubble.

And, yes, being able to see bubbles has practical applications; for one, chasing the latest bubble isn’t the best career path.

If you want to see the craziness that was going on, and the fact that some people called the bubble in 2004 or earlier , look at the archives at the Housing Bubble Blog or Housing Bubble Casualty.  Christopher Thornberg was one of the few economists to get it right.  Finally, it’s important to note that the housing bubble is in fact world wide (UK, Spain, China, etc) and started first outside the US.

Tony 

As I’ve mentioned before, I have a couple companion sites that use a secure connection (https). But when you go to these sites, you get an error message from the browser. Basically, what is happening is this:

1. A secure session needs a security certificate.
2. My sites are using my hosting company’s certificate (located at webfaction.com)
3. But my sites have their own domain (e.g. trac.factoryswblog.org) which does not match the certificate’s domain (e.g. web13.webfaction.com)
4. So the browser displays a message, because if I were running an e-commerce site, you should be concerned (and not do any business with me until the problem is fixed).
5. But I’m not running a business (and do not want to spend the extra money for a fixed IP address and my own security certificate), so you can trust me and accept the certificate. With Firefox 3, you can add a permanent exception (so the security message only appears the first time), unlike Firefox 2, IE6, and Opera, where the message appears every time you visit.

Here are some pictures of what happens (other browsers should be similar):

Firefox 2

Press the OK button to view my site.

Internet Explorer 6

Press the Yes button to view my site.

Firefox 3

You need to add an exception, so start by pressing the Or you can add an exception… link

which brings up the display below.  Click on the Add Exception button.

which brings up this dialog.  Press the Get Certificate button.

Now we’re almost done.  Press the Confirm Security Exception button, and Firefox 3 won’t bother you any more (assuming you have left Permanently store this exception checked).

Tony

Deelip Menezes has a 5-part series up giving a short (but very useful) hands-on tour of Siemens’ Synchronous Technology. It’s certainly not comprehensive, but it gave me a better idea of what it (ST) really is, instead of the marketing buzz.

Originally, I was quite skeptical. Basically, Synchronous Technology is adding direct editing (like SpaceClaim) to Siemens’ Mechanical CAD programs (SolidEdge, NX) but keeping some parametric-driven (“design intent”) goodness. I’m less skeptical after reading Deelip’s series – at a minimum, it does seem like a very good user interface. But I still wonder what an expert Pro/E user would think. Unfortunately I don’t have the time or knowledge to really evaluate it.

Tony

I really enjoy late 19th and early 20th century English literature – not just serious authors like Evelyn Waugh who never go out of print, but also the rivals of Sherlock Holmes. The internet (especially project Gutenberg) has made available many books I have not been able to find in print.

Since I lived in Silicon Valley during the dot-bomb bubble, I always get a kick out of reading Arthur Morrison’s The Affair of the “Avalanche Bicycle & Tyre Co.,Ltd.” Although it was written in 1897, it sounds just like the internet bubble. The story appears in the Dorrington Deed Box, which is now back in print – and available online.

Tony

I was looking for a new vacuum cleaner recently. Although they seem to be capable, if pricey, vacuum cleaners, I was repelled by the Dyson marketing hype – which seems to play up the lone inventor, who comes up with better ideas for everything he touches. On closer examination, Dyson’s claims seem a little fishy. My information is from Dyson’s web site and this Amazon product blurb.

“5 years and 5,127 prototypes later, the world’s first cyclonic bagless vacuum cleaner arrived.”

OK, let’s think about that:

• Assuming a normal American work schedule, there are about 2,000 work hours per year, so that means Dyson was coming up with a new prototype every 2 hours? (10,000/5127=1.95hrs/prototype). Hmm, that doesn’t make sense. Even assuming 10 researchers, that would be about 20 hours per prototype, which isn’t enough to design, make, test, and evaluate.
• But Dyson had trouble making his patent renewal payments (currently starting at £140 per year per patent, after the fourth year), so I don’t think he was paying 10 people. So we’re back to 2 hours per prototype – yeah, right!
• Elsewhere the hype implies three researchers – so that’s 1 prototype every 6 hours! But I wonder why, if Dyson could pay two other researchers, why he couldn’t pay the much smaller patent renewal bill?
• I think 5,127 prototypes is supposed to impress people. It doesn’t impress me. If you are truly engineering (and not tinkering), you shouldn’t have to do that many prototypes. Fluid flow principles haven’t changed recently. Admittedly, it’d be easier today (with fast computers and affordable simulation software) but even in 1978,with a calculator and good engineering knowledge you could do a lot.
• There’s a whole area called DOE (Design of Experiments) that is about minimizing the number of experiments you need to do. Good result analysis (matching real results with predictions) also results in fewer wasted prototypes – and deeper understanding of the problem domain.

Dyson likes to talk about their reliability.

But a UK survey showed they were the only brand with below average reliability.

“Only Dyson doesn’t lose suction
Dyson Root Cyclone technology uses 100,000G of centrifugal force in the cyclones to filter dust and remove dirt from the airflow efficiently. Because there is nothing to obstruct the airflow, it doesn’t clog and doesn’t lose suction.“

But the Dyson definitely can clog – here’s one way to clean it. The pre-motor filter needs washing every six months.

“The original team of 3 Dyson engineers grew to 350 scientists in a new research center, …”

I’m not too impressed – 350 R&D people (I doubt most are really scientists) to support a product line of pretty similar upright vacuums, a canister vacuum, a hand held vacuum, a clothes washer, and a hand dryer. Maybe that’s why the machines are made in Malaysia, unlike similarly priced machines from Bosch, Miele, etc which are still made in Europe.

My vacuum cleaner thoughts:

• Dyson probably makes good vacuums – I’ve seen too many positive comments. However, I do think they are over-hyped.
• I went with a canister vacuum, because I wanted something light (so my wife could use it), quiet, variable speed, and that could easily reach under furniture. I bought a bagged Bosch canister vacuum; so far I’ve been very happy with it. The Dyson canister vac was out when my wife heard the price.
• My old vacuum was a non-Dyson upright bagless. Its filters most definitely did clog eventually; maybe Dysons are better about that. There is definitely some convenience to the bagless, and it’s very nice to see all that dust swirling around.
• I think my new bagged vacuum cleans better than my old bagless – for one, the dust is fluffed up with a bagless so it looks impressive, but when you scrunch it down, you don’t have much.

Tony

No, I’m not quitting, it’s just time for a quick reflection.  I’ve done 20 posts in 25 week.  That’s a bit less than my goal of a post a week, but not bad considering everything going on in my life.

I’m going to be re-doing the website a bit (not a major makeover, but adding some necessary improvements).  I’m also going to finish some “light” and off-topic posts I have in the pipeline.  Then I plan to get back to some of the series.

My biggest regret is that the PCB series has stalled.  It may be a bit more time to get going (since I actually have to learn Eagle PCB – my previous boards used software from a now (deservedly) defunct company), but I will finish it.

I may delete comments which appear to be non-obvious attempts at comment spam or SEO (search engine optimization) – if a comment doesn’t add to the conversation (either on or off-topic) and has a gratuitous link to a website, it may go poof!

Tony

This is an extended response to a question asked by Gary Mitchel on his Feed Forward blog: Where do you go for depth? I have so many thoughts on this subject, and the broader topic of good information sources, that it will take several posts.

First off, I am a book junkie. I might be in hibernation now (after marriage and children), but if I go to a book store, especially a used one, it’s very likely I’ll come out with 2-3 books. I don’t always read the books right away, but I always buy because I’m interested in what’s inside, not just the covers.

The best places to go for information depends on what you’re looking for. It’s different if you want to think about perennial human problems (philosophy, religion, political philosophy), current events (history, politics, social trends, etc), technology, or other areas that I won’t cover.

Each type of media has its own strengths and weaknesses. Since I’m not writing a book here, I’ll just give some opinions of mine.

Paper has the best readability – it’s so easily get comfortable with a book or magazine. And if you need to refer to multiple sources, it’s so easy to spread a whole bunch of paper, books, or magazines out – OTOH, most of us can’t afford the equivalent number of monitors! Reading a PDF file or HTML file on a monitor just isn’t the same.

When I was first programming, I did a lot of print outs. Now I hardly ever print anything out. Partly the programs are longer – long program listings aren’t so useful. Mainly I think it’s because modern development tools are so useful – like searching in all the files, showing the difference between two versions, going to function definitions with a click, etc. Larger monitors also help (if I were back on a 640×480 screen, I’d be printing code a lot more).

One problem with print is it quickly runs into space limitations. Complete documentation of any reasonably complex system (say the .NET framework) will take thousands of pages. Magazines have severe space limits. Space is much cheaper online, so it’s possible to have much more information on line.

But it’s harder to read long pieces on line. The blog format especially isn’t well suited to long pieces – they need to be broken up. For example, I’m breaking up this top into at least three posts, so that each post will be somewhat manageable in length. There is a plus in splitting posts up – it means I can write it a bit at a time, which is easier to do. This is a return to the earlier days of publishing, the time of Dickens, when novels were published serially (often as the author was still working at it!) – we’re also seeing this in computer books (e.g. Manning’s Early Access program).

Another online (and computer) advantage is search. It can be so much faster finding something online than using trying to sort through the indexes of a bunch of books – and you still might not find it. Of course, now some sites let you search books online (Amazon, O’Reilly’s Safari, etc) so this can be the best of both worlds – use search to finds the books, then read them in paper form.

A web disadvantage is lack of permanence – links grow old, web sites disappear, and not everything is cached. Paper is still readable hundreds of years later (well, if it’s quality acid-free, not pulp).

As I’ve mentioned, I’m a book person. I don’t care much for audio (except for music) or video (OK, I do love Looney Tunes), especially for technical topics. Print material lets me go at my own speed, skip the stuff I know, and concentrate on what is most important. I’m sure audio (including podcasts) and video have their uses.

My recommended reading for this post is Evelyn Waugh’s Scoop and Dorothy Sayer’s Murder Must Advertise. Scoop is totally hilarious and still relevant to today’s journalism (especially considering the number of journalists who have been caught making up stories). Murder Must Advertise is also an enjoyable read, especially the parts about the advertising agency (the copywriters don’t like the art people – kind of like Gary Mitchell and his art director – but they all hate the customer).

Tony