Strobaek Blog

Dear Friends and Family,

The best wishes for the holiday season and the new year.

I have recently read two manuscripts from Manning: SOA patterns by Rotem et all and PowerShell and WMI by Siddaway. None of them are published yet, but both are available through Mannings MEA program.

Like I have done previously I will try to write up a small review of each, but right now I do not have the bandwidth, so it will have to wait a little.

I can say that I found both books interesting. Howerver, PowerShell and WMI is not the most exciting subject, so this was somewhat difficult to get through. A lot of very good and usefull examples, though, which helped a lot.

My last review for Manning Publications Co. can’t have been all bad, because they asked me to do another one. The book this time is Machine Learning in Action by Peter Harrington and currently available in MEAP. The review is a so called “2/3” review as the book is not complete. I had the pleasure of reading chapters 1 through 10 as well as some of the appendixes.

Many years ago I did my Master thesis on the mathematical properties of artificial neural networks. I haven’t been working much in this area lately, so it was quite fun to “re-visit” some of the theory and applications used both in ANN and machine learning.

The book is very application oriented and gives some very good and illustrative examples of algorithms which can be used for classification, forecasting or unsupervised learning. It uses Python for all the code examples, but gives very good directions on how to install and use it, so if you are new to Python or have never used it before, this should not hinder you from getting value from the examples.

The author has included a lot of references to background material, enabling the reader to seek more information on areas of specific interest.

One area I find is a little weak is the handling or explanation of the underlying statistics. Machine learning is really just a form of Non-linear optimization and we know when these models are better then OLS (Ordinary Least Squares) or “regular” regression. If a certain set of conditions are met, the OLS estimate is the Maximum Likelihood (ML) estimate, and then we really can’t do any better. What this means is, that machine learning or neural networks or whatever we call it, will only be better if these conditions are not met.

One could fear, that the inexperienced user, would draw conclusions which on first sight would seem correct, but which would actually be wrong, because the underlying model was incorrect or the supplied data did not support it.

This being said, I found the book a very good read and a good introduction to Machine Learning.

I was asked to do the 2nd review on the book RabbitMQ in Action by Videla & Williams (Manning Publications Co.). Link here for those interested. The book is currently available in MEAP.

RabbitMQ is an efficient, highly scalable, and easy-to-deploy queue that makes handling message traffic virtually effortless.

The book started out with a really nice historical overview of message queues. It then continued to walk through different aspects of Rabbit, giving good examples and real life stories. The prose flows nicely and the authors are quite capable of keeping ones attention.

One importing thing to note: this is a book primarily for the Unix gang. If you have never played around with Unix or Linux and Python you will most likely not be able to run the examples. I only got chapters 1 through 8 and later chapters does promise to introduce java and .NET and look at how to install and run Rabbit on other platforms, but I have not read those chapters yet, so I cannot say how they are.

This said, the book is still very recommendable for those interested in learning more about Rabbit.

I really enjoy logical and mathematical problems, so when I came across the “world’s hardest easy geometry problem” I was quite excited. I mean, how difficult can it be, right? 180 degree in a triangle and you are set.

I dare anyone to try and solve the problem below: find the angle . Sure you can measure the angle, but that is cheating. Grab pen and paper and let me see your “proof”; I would be very interested in comparing notes. I spend many hours for many days solving this, but then again, I’m not the sharpest knife in the draw.

Update: I forgot to write, that you are only allowed to use simple geometry. No trigonometry is allowed.

Some great news on the job front. December 1st I’ll start as Senior Consultant at Microsoft.

I’m really thrilled about having been given this opportunity to work for the company, that more or less has made the technologies which have been a major part of my professional life for the past 15 years.

It is going to be challenging, but it  is also going to be an exciting journey and – without a doubt  - a lot of fun.

Just read a nice blog post by @4nd3rs (in Danish) about his considerations about online backups; what to use and local vs. remote backup.

In the following I will try to describe my own setup. It has been a work in progress, but right now I feel it meets the requirements of myself and the family.

As any other modern family we have a number of computers running both Windows and OSX. When we moved into our house, I decided I did not want to run any cables anywhere or rather my wife decided we did not want to do this, so all devices are connected using wireless to the internet and the NAS.

The main storage and backup devices is a Drobo FS with 3 TB of storage. Data Robotics has their own concept of RAID, called BeyondRaid, and having three disks in the NAS enables it to exercise protection for single disk failure. The Mac is using the Drobo for backup via TimeMachine. Apart from shared documents the main content of the Drobo is pictures and music as the device also serves as storage for our Sonos music system. Whatever requirements the Windows machines have for backup, it is handled remotely.

For remote backup we recently moved from using JungleDisk and Amazon S3 to iDrive. For iDrive I have a Pro-account where the Drobo is back up to and each other family member has their own Basic account. The professional account is $5/month for one PC and 150GB. They have a family pack for 5 PCs and 500GB, which is $15/month; I guess we will move here when the need raises.

The main reason from moving away from Amazon was cost. It is dead cheap if you only have a small amount of data, but can get quite expensive if you have a lot, especially to extract the data if required.

We also use DropBox and each of us has an account. Personally I can’t remember when I used an USB stick last. It is just great for “moving” files back and forth, e.g. between work and home, and also for file sharing.

This is a test of formatted code:

        public CompleteStorageService(string connectionString, string fileName)
        {
            if (connectionString == null)
            {
                throw new ArgumentNullException("connectionString");
            }
            if (fileName == null)
            {
                throw new ArgumentNullException("fileName");
            }

            this.connectionString = connectionString;
            this.fileName = fileName;

            this.syncLock = new object();
        }

Thanks ploeh …

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