The C10K problem [Help save the best Linux news source on the web -- subscribe to Linux Weekly News!] It's time for web servers to handle ten thousand clients simultaneously, don't you think? After all, the web is a big place now. And computers are big, too. You can buy a 1000MHz machine with 2 gigabytes of RAM and an 1000Mbit/sec Ethernet card for $1200 or so. Let's see - at 20000 clients, that's 50KHz, 100Kbytes, and 50Kbits/sec per client. In 1999 one of the busiest ftp sites, cdrom.com, actually handled 10000 clients simultaneously through a Gigabit Ethernet pipe. And the thin client model of computing appears to be coming back in style -- this time with the server out on the Internet, serving thousands of clients. With that in mind, here are a few notes on how to configure operating systems and write code to support thousands of clients. Contents Related Sites See Nick Black's execellent Fast UNIX Servers page for a circa-2009 look at the situation. Book to Read First I/O frameworks I/O Strategies 1. 2.
chicagoruby/Windy-City-DB-Dataset Gabriel Cousens Juice Fasting Tree of Life EU - Israel Detox Rejuvenation Organic Fast Body Cleanse גבריאל קאזנס קזנס צום צומות מיצים צומות ניקוי גוף רעלים עץ החיים ישראל אורגני התחדשות סדנה סדנת High-Performance Analytics - L'architecture Big Data de SAS Hadoop, MapReduce, NoSQL, Appliances… tous ces termes techniques fleurissent pour décrire le phénomène Big Data, à l'origine du Big Analytics chez SAS. Si le Peta-octet n'est pas encore l'unité de base des applications décisionnelles, on peut estimer que les données disponibles pour le monde analytique vont augmenter et se diversifier. La capacité à valoriser et utiliser ces informations dans un laps de temps réduit est l'enjeu majeur des trois prochaines années. Le Big Data et l'Analytique : la réponse à des enjeux métiers Nous vous proposons en téléchargement gratuit un livre blanc qui énonce les utilisations et les bénéfices métiers dans différents secteurs d'activité. Ce sont autant d’exemples apportant un éclairage pertinent sur la gestion, le stockage, l'analyse et l'exploitation d'importants volumes de données réalisés avec SAS dans le contexte du Big Data. SAS® High-Performance Analytics Server : une offre dédiée Exploration visuelle des données avec SAS® Visual Analytics
Redis 5 Ways To Hack Your Brain Into Awesomeness | Cracked.com - StumbleUpon Much of the brain is still mysterious to modern science, possibly because modern science itself is using brains to analyze it. There are probably secrets the brain simply doesn't want us to know. But by no means should that stop us from tinkering around in there, using somewhat questionable and possibly dangerous techniques to make our brains do what we want. We can't vouch for any of these, either their effectiveness or safety. All we can say is that they sound awesome, since apparently you can make your brain... #5. So you just picked up the night shift at your local McDonald's, you have class every morning at 8am and you have no idea how you're going to make it through the day without looking like a guy straight out of Dawn of the Dead, minus the blood... hopefully. "SLEEEEEEEEEP... uh... What if we told you there was a way to sleep for little more than two hours a day, and still feel more refreshed than taking a 12-hour siesta on a bed made entirely out of baby kitten fur? Holy Shit!
Box plot In descriptive statistics, box plot or boxplot is a convenient way of graphically depicting groups of numerical data through their quartiles. Box plots may also have lines extending vertically from the boxes whiskers indicating variability outside the upper and lower quartiles, hence the terms box-and-whisker plot and box-and-whisker diagram. Outliers may be plotted as individual points. This is also called a "box and whisker plot". Box plots are non-parametric: they display variation in samples of a statistical population without making any assumptions of the underlying probability distribution statistical distribution. Types of boxplots Figure 2. Figure 3. Box and whisker plots are uniform in their use of the box: the bottom and top of the box are always the first and third quartiles, and the band inside the box is always the second quartile (the median). Some box plots include an additional character to represent the mean of the data. Variations Figure 4. if and John W.
MVC, MOVE - Or Simply A State Machine One problem with a state machine approach compared to MVC is that it isn't as familiar. Do you use a Moore or a Mealy machine? A combination of the two? Most people don't use state machines to model the flow of an entire web application, so if you try it out, you might feel like you're on your own. It can be worth it, though. Another benefit was that the state machine library I used allowed me to audit the trail of states as they happened. There's one very important thing that nobody has mentioned yet: state machines look ugly in your code. Statecharts are a way to model state machines without explicitly writing out a ton of redundant states. I believe statecharts are to MVC as Clojure is to every mutable state language out there.  See "Out of the Tarpit" for why state and complexity are closely related:  The original article on statecharts:
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Couchbase Server Manual 2.0 - Chapter 9. Views and Indexes Couchbase Server is a NoSQL document database for interactive web applications. It has a flexible data model, is easily scalable, provides consistent high performance and is ‘always-on,’ meaning it is can serve application data 24 hours, 7 days a week. Couchbase Server provides the following benefits: Flexible Data Model With Couchbase Server, you use JSON documents to represent application objects and the relationships between objects. All of these features of Couchbase Server enable development of web applications where low–latency and high throughput are required by end users. Couchbase Server and NoSQL¶ NoSQL databases are characterized by their ability to store data without first requiring one to define a database schema. Relational databases store information in relations which must be defined, or modified, before data can be stored. Architecture and Concepts¶ Nodes and Clusters¶ In this description: Cluster Manager¶ Data Storage¶ RAM Quotas¶ vBuckets¶ Caching Layer¶ Disk Storage¶
Couchbase Developer's Guide 2.0 - Chapter 2. Modeling Documents Couchbase Server is a NoSQL document database for interactive web applications. It has a flexible data model, is easily scalable, provides consistent high performance and is “always-on,” meaning it is can serve application data 24 hours, 7 days a week. Couchbase Server provides the following benefits: Flexible Data Model With Couchbase Server, you use JSON documents to represent application objects and the relationships between objects. All of these features of Couchbase Server enable development of web applications where low–latency and high throughput are required by end users. Understanding Couchbase Concepts¶ Before you develop applications on the Couchbase Server, you will want to understand key concepts and components that are related to application development on Couchbase Server. Couchbase as Document Store¶ The primary unit of data storage in Couchbase Server 2.0 is a JSON document, which is a data structure capable of holding arrays and other complex information. Data Buckets¶
Couchbase Server Manual 2.0 - Chapter 9. Views and Indexes - 9.5. Writing Views Couchbase Server is a NoSQL document database for interactive web applications. It has a flexible data model, is easily scalable, provides consistent high performance and is ‘always-on,’ meaning it is can serve application data 24 hours, 7 days a week. Couchbase Server provides the following benefits: Flexible Data Model With Couchbase Server, you use JSON documents to represent application objects and the relationships between objects. This document model is flexible enough so that you can change application objects without having to migrate the database schema, or plan for significant application downtime. Even the same type of object in your application can have a different data structures. All of these features of Couchbase Server enable development of web applications where low–latency and high throughput are required by end users. Couchbase Server and NoSQL¶ NoSQL databases are characterized by their ability to store data without first requiring one to define a database schema.
The NoSQL “Family Tree” A few weeks back, one of our marketing teammates caught me explaining the NoSQL product landscape to some new employees, and they thought it would make a pretty infographic. I use this diagram a lot to help customers and business partners understand some important NoSQL basics: Create a free Cloudant account and start the NoSQL goodness NoSQL arose from "Big Data" (before it was called "Big Data") During the late 1990s and 2000s Google, Amazon, and Facebook were growing through the roof. As you can see in the diagram, people used these ideas in different ways to create many of today’s popular NoSQL databases. NoSQL is not "One Size Fits All" The color coding in the diagram highlights the fact that NoSQL products evolved to meet specialized workloads. That's not to say these solutions aren’t used for multiple purposes. Vendor-driven versus Community-driven NoSQL This is the last distinction I’d like to make. In Summary