n o t e 1 9 . c o m

Databases are so yesterday, Availability vs. Consistency, the CAP theorem, failure is the norm, and network partitions these are just a few terms associated with Internet scale and modern distributed systems. In this world, Paxos is a critical algorithm for implementing a fault-tolerant distributed system and is not the famous Island in Greece, and the Clash of Cultures refers to distributed systems based on ACID semantics vs. modern Internet systems that focus on BASE.

Gone are the days where distributed objects (CORBA, e.g.) were synonymous with distributed systems. Now days for a vast array of applications, performance and availability is what counts and ACID reliability is only considered a requirement for areas where direct currency is involved, e.g., ATMs or checkout phase from an e-store.

I’ve started getting interested in this area and this is the first of a series of notes on modern distributed systems. This first note is simply a collection of the important terms in this space.

ACID: Atomic, Consistent, Isolated, Durable.

BASE: Basically Available, Soft-state (or scalable), Eventually consistent.

CAP Theorem: Consistency, Availability and network Partition tolerance (Prof. Eric Brewer, UC Berkeley). In a distributed, system, you can have only two of the three properties of CAP.

A German search company called Proximic has introduced a contextual based search engine (as opposed to keyword based) that promises to find more relevance in search results. I’ve downloaded their Firefox extension which displays related pages as you browse the web. The related pages it displays appear to be quite good. But I need to use it for a while longer to see if they are useful. There was also an article (and here is one more) about this company on today’s paper. Here is the Scoble Show interview with the Proximic founders.

Logitech Harmony software does not have an entry in its supported set of devices for Apple TV. But I managed to get it to work. There may be multiple ways of doing this. But this is how I got it to work: first add a Digital Music Server as a Device, and then add an Activity that informs the remote that you’ll be using your TV to control the sound. I’ve created a screencast of the steps.

Note: make sure that you’ve not paired your Apple TV with the Apple TV remote. If you do, then Apple TV will only respond to the remote that it was paired with.

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This morning my neighbor Tom & I bicycled to work (my first time). I had purchased a GPS device in the anticipation of this bike ride and today was the day to put this GPS track recorder to good use. I used GPSBabel to download the data to my computer and then with a small Ruby program I converted the data to a Google map. I need to update this program to also display the distance traveled and other useful bits of information that is in the GPX file — one of these days.

The Google Book project started a few years ago, where they started scanning the library collection of a number of universities. Well starting today, you can now embed a reference to the digital version of the book in your own blog. You can select any part of the book to be the image which you embed in your blog. Very cool. Finally you can read the old classics from the comfort of your own blog. The Google Book reader displays each page as an image. You can zoom in and out, but you cannot select or copy the text.

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If you want to convert your favorite song to a ring tone, look no further. Ambrosia’s excellent iToner is the program for creating and transferring ring tones to the iPhone. Unfortunately, you cannot use any of the songs that you’ve bought on iTunes because of copy-right protection.

Amazon in partnership with the National Archives is now offering newsreels in DVD format. They have started to digitize the National Archive collection and using the Amazon owned CustomFlix technology to create the DVDs on demand. I just ordered a copy just to see what it is like. Given the public domain nature of the content, I wonder if I can convert parts of it to Adobe Flash and show it on this blog?

WordPress now offers a video player. You can upload a video in a number of different formats, they convert it to Adobe Flash and offer a very nice looking player.

I used SnapZ Pro X to capture a couple of minutes of video from the Red Star: Red Army Chorus and Dance Ensemble DVD that I recently ordered from Amazon. I then down-sampled the video with QuickTime Pro (from 800 MB to 5 MB) before uploading it to my WordPress account. The conversion to Flash took a while and during this time I had no idea what was going on. The net result looks pretty good, however.

Today I tried to copy a DVD that I own to a network drive so that I could watch the movie from any computer on my home network. After a number of false starts and paths that lead to no where, I managed to find a solution that works:

To copy the DVD, you need a DVD copy application that can decrypt the DVD. I found Xilisoft DVD Copy does a good job (it is however not free: $49). The copy creates a folder for the movie and two sub folders: AUDIO_TS and VIDEO_TS. You can try the DVD Copy for free but it compresses the video and you’ll lose quality (although it looked pretty good). To get the full quality you’ve to buy it.

Once you’ve copied the DVD, I tried playing the copy using Apple DVD Player. This player refuses to play, giving the following error:

After some more Google searching, I found a free player (VLC) that works pretty well (the DVD menu, audio selection, chapter selection and a lot more).

I had never heard of ning.com until today. It is a site that allows users to create their own social networking sites (SNS). Since users can create their own SNS, it is a very much a hit or miss to find something useful. But there are useful sites, e.g. Hiking Trail Reviews.