Even in times of a growing market of specialized NoSQL databases, the relevance of traditional RDBMS doesn’t decline. Especially when it comes to the calculation of aggregates based on complex data sets that can not be processed as a batch like Map&Reduce. MySQL is already bringing in a handful of aggregate functions that can be useful for a statistical analysis. The best known of this type are certainly: COUNT(x), SUM(x), AVG(x), MIN(x), MAX(x), STD(x) In addition, there are a number of statistical evaluations which are also worthwhile - if not even more interesting and meaningful, but with MySQL only producible with greater efforts. What about the different averages? The harmonic average, a weighted average or the geomean? What is in the course of this with the aggregate product? How do we determine the mode, the median? The covariance? ...

We provide pre-built images for several open-source operating systems. Please note that: Every image contains the latest software as of the day the image was built. Performing updates is on your own, and may require looking for documentation to read using your favourite search engine. Default usernames and passwords, where required, can be found next to the download link of each image. You are warmly invited to create your own user, or at least to change passwords, if you intend to use the images in a public environment. ...

Lynis es una herramienta para realizar auditorías en sistemas Unix. Escanea el sistema en busca de vulnerabilidades y fallos de seguridad. También muestra información general del sistema, paquetes instalados y errores de configuración. Su objetivo es ayudar en el proceso de auditoría, actualización del software y escaneo de vulnerabilidades y malware en sistemas Unix. Se puede ejecutar sin necesidad de instalación. Se puede utilizar en auditorías Basel II, GLBA, HIPAA, PCI DSS y SOX (Sabarnes-Oxley). La documentación está disponible en línea. ...

Pere Roura (Universitat de Girona) y Daniel Oliu nos cuentan en ”How energy efficient is your car?,” AJP 80: 588-593, July 2012, cómo medir de forma práctica la eficiencia energética de tu propio coche. Como ejemplo utilizan su Volkswagen Lupo 3L, un coche diseñado para ser muy eficiente con un motor diésel de tres cilindros, un peso de 830 kg y un consumo récord de solo 3 litros a los 100 km. Según su estudio solo el 28% de la energía del combustible se transfiere a las ruedas, lo que sin lugar a dudas es todo un récord en eficiencia para un vehículo comercial. Sin embargo, también nos recuerda que el 72% de la energía del combustible se pierde por aerodinámica, fricción, pérdidas mecánicas y térmicas. En los vehículos de gasolina, la eficiencia suele ser mucho menor. Para un vehículo típico se estima que solo el 12-13% de la energía del combustible se transmite a las ruedas, según el estudio de Joseph A. Carpenter, Jr. (Department of Energy, USA) et al., ”Road Transportation Vehicles,” MRS Bull. 33: 439–444, 2008 [copia gratis], del que he extraído la figura de abajo. ...

Arthur W. Burks / Herman H. Goldstine / John von Neumann PART I ​1. Principal components of the machine 1.1. Inasmuch as the completed device will be a general-purpose computing machine it should contain certain main organs relating to arithmetic, memory-storage, control and connection with the human operator. It is intended that the machine be fully automatic in character, i.e. independent of the human operator after the computation starts. A fuller discussion of the implications of this remark will be given in Sec. 3 below. ...

I was in charge of scaling Dropbox for a while, from roughly 4,000 to 40,000,000 users. For most of that time we had one to three people working on the backend. Here are some suggestions on scaling, particularly in a resource-constrained, fast-growing environment that can’t always afford to do things ”the right way” (i.e., any real-world engineering project ;-). If people find this useful, I’ll try to come up with more tips and write a part 2. ...

This thread has 2 Posts, and is categorized as following. You can scroll down to the Point you are looking for. Post 1: Getting Root / S-OFF to your Wildfire. A Short overview and Guide Custom ROM List Post 2: Custom Kernels List Radio (Baseband) List RUU List (ROM Update Utility - Getting back to stock) Custom Recoveries (ClockWorkMod) Themes List Misc tweaks / hacks » 3xeno | xda-developers.com

[ROM] [UPDATE1] [{^NaRkDrOiD IcX3^}][4.0.3. LP8/LP9][MejorasVarias][Mods][Extras][Novedades y mucho más!] [ ¿¿TE LO VAS A PERDER?? ] » anarko919 | htcmania.com

The thing to remember, above all else when writing JS code, is that it’s a dynamic language. This means there are a lot of ways to do things. You don’t have to deal with strongly typed classes, or some of the more complex features from languages, like C# and Java. This is both a blessing and a curse. You can read an article on the history of JavaScript here, but the gist of it is that Brandon Eich, in 1995, was hired by Netscape to design a language. What he came up with was the loosely typed language that we know as JavaScript. Over the years, it became ”standardized” as ECMAscript, but, throughout all the browser wars, the various browsers implemented these features differently. This, naturally, lead to a lot of sleepless nights for web developers. This problem, when combined with the fact that JavaScript was considered to be most applicable for manipulating images and performing quick bits of validation, led JavaScript to, incorrectly, be viewed as a terrible language. ...

We built Twemcache because we needed a more robust and manageable version of Memcached, suitable for our large-scale production environment. Today, we are open-sourcing Twemcache under the New BSD license. As one of the largest adopters of Memcached, a popular open source caching system, we have used Memcached over the years to help us scale our ever-growing traffic. Today, we have hundreds of dedicated cache servers keeping over 20TB of data from over 30 services in-memory, including crucial data such as user information and Tweets. Collectively these servers handle almost 2 trillion queries on any given day (that’s more than 23 million queries per second). As we continued to grow, we needed a more robust and manageable version of Memcached suitable for our large scale production environment. ...