Category Archives: Ramblings

Updated Site

scottpreston.comI’ve decided to refresh the theme of my blog. You may notice it’s simple, and minimalist in style. You won’t find it changing too much in the coming weeks, except for a few more pages or widgets on the sidebar, and maybe a header image or two.

Correlation vs. Causation

What’s the difference between being linked and being caused? If I tell you that every time I dropped a water balloon on the ground it broke. You could say gravity caused the water balloon to break. But what if I didn’t tell you were always filling the balloons to their maximum capacity and they were dropped on rough, almost sharp concrete, would you make that same conclusion that gravity caused water balloons to break?

What if they were half full and landed on grass and none broke? Would you conclude that gravity does not cause water balloon breakage?

It seems today the public DEMANDs an explanation for everything, if A, then B. But in just about every case it’s never that simple.

The real explanation of why a water balloon breaks is when the pressure of the water inside the balloon exceeds the tensile strength of the rubber. Sharp objects exert more force per unit square meter than other items such as grass or perfectly flat surfaces. However this is too complicated for journalist catering to a public with poor and getting worse science understanding and desire to create sensation and get attention.

To truly know something is causal  (A implies B) is hard and takes time.

Don’t confuse correlation with causation. While these examples sound funny, you can read about them every day, especially with medical studies and social sciences.

100 Monkeys & Predicting The Future

The Story: You’ve got a 100 monkeys flipping coins. Eventually after 10 tries there’s a single monkey left that managed to flip it 10 times in a row heads…

Same Story: All 100 monkeys have a theory that use that use to predict coin flips. All but 1 monkey was successful 10 times and is 100% accurate.

Same Story: I can predict the future of the middle east, the economy or the weather because I’ve done so in the past with my theories.

If you look at this you realize how susceptible we all are to people that promise us they can predict the future. I suspect that science combined with clever statistics or even complicated mathematics is now the new bones, tarot cards, or crystal balls.

Isn’t it funny how we haven’t changed all that much?

Amazon Reviews

I really don’t understand these reviews. I’ve sold hundreds of books and can barely get a single review, yet this book has been released just over a day and it has 54 reviews. Half 5 star, half 1 start. I’m not sure how someone can read a book in 24 hours then find the time to write a fair review about it. I don’t ever plan on reading this book, but I just think that something else has to be at work i.e. paid reviewers.

Rebranding Progress

I started out purchasing a WordPress theme, thinking that I could just find one, configure it, and be done… Wrong. The theme didn’t work and it did not have any helpful support. I should have done it myself and am now doing that.

I have a mantra I’m working on but I don’t have the wording quite right, so stay tuned…


Deployments With RSYNC and Git

Over the past few years I’ve been trying to get away from using FTP and deploying an entire directory to just update a web app. I’ve used services like Springloops and even tried a tool like Capistrano, but nothing really was 1) Simple and 2) Free until I wrote my own bash script. Here’s basically what you do.

  1. Create SSH keys between your local machine and your remote box.
  2. Create a bash script with the following code.
rsync -rtv --progress --exclude-from 'exclude-list.txt'  $LOCAL $REMOTE
ssh 'chown -R user:nobody /home/useraccount/public_html'
ssh 'chmod 750 /home/useraccount/public_html'

So set your LOCAL to your local directory path, REMOTE to your remote path with your user that you have your deployed files.

Note the rsync parameters, I’ve not chosen -a because that will also copy my local permissions, users and groups vs. the remote permissions users and groups.

Finally I’ve added an excludes list, which I’ll add things like “.git/” so that the git repository does not get sync’d and copied.

Now if you’re stuck into using FTP and just want to export what’s changed. I use this little script:

tar czf ~/Temp/new-files.tar.gz `git diff --name-only SHA1 SHA1 | grep -w '.php'`

This allows me to create a tar.gz of just what’s changed between two commits and in the case above, just grab .php files. You can remove everything past | grep if you want everything.

How to get a car for free

I was thinking about this last night after a conversation with a friend and I thought I’d write a small post about it.

To get a car for free is all about timing the resale value of a car and having a little cash on hand. Take my truck a 2007 Tacoma 4WD. It has a resale value of $15,000.

Let me give you the resale values of the same make & model on either side of mine:

2006 – $12,000
2008 – $15,000
2009 – $16,500

Now if I wanted to keep my truck forever I would just trade-up once a year for a car about the same cost as mine.

Take it further.

Let’s say I really hunt for a good deal and I get a 2008 on the lower end ($13.5k), then a year later I’m able to sell it and make a little profit, $2K. I do this a few years in a row now I could be up to a $20K car/truck. Still not paying anything other than sales tax. If you’re a good wheel & dealer, you can offset this cost by your negotiation skills.

So now this is how you get and keep a car for free, the key is timing the resale value and year you’re purchasing.

iPad Screen Size in Safari

I was very surprised when I Googled the screen size for the iPad nothing showed up. I actually had to create a DIV and experiment until I found the correct size.

  • The viewable area in landscape mode is 980×660.

You can also adjust the viewport via:

<meta name=”viewport” content=”width=device-width” />

which is what is recommended by Apple. I just thought this might be useful as you are measuring pixels for a page layout.