KUKURUKU HUB

Brain Overclock or Internal Virtualization of Consciousness

Written by leon_3

Do you remember this movie? What is it doing here? Why the hell is such post on Kukuruku? I guess, because I think that the main component of IT is human, or rather our brain. I’ll tell you about another possibility of using your brain a bit more effectively. Everything described here has been tried out by me. It’s important to note that I’ll highlight if I haven’t tried something. I didn’t use any drugs or devices. Popular methods have only been used. And yes, it’s devastatingly realistic. Having tried it once, you'll never resist spreading the word. To avoid unnecessary cries in comments, I’m asking all staunch defenders of any religion or faith, and all the esoteric representatives to down-vote me and stop reading further. You’ll find no philosophy and great universal mysteries in this article. The rest of you are welcome — I’ll try to tell you about

Writing a File System in Linux Kernel

Written by kmu1990

Who This Article is for There are no complex or difficult concepts in this article, all required is a basic knowledge of the command line, the C language, Makefile and a general understanding about file systems. In this article I am going to describe the components necessary for development inside the Linux kernel, then we’ll write the simplest loadable kernel module and, finally, write a framework for the future file system. It’s a module that will register quite a useful (for now) file system in the kernel. The ones familiar with development inside Linux kernel may not find anything interesting here. Introduction A file system is one of the central OS subsystems. File systems continue to develop as operating systems evolve. Currently we have an entire heterogenetic zoo of file systems, from the old “classic” UFS , to the new exotic NILFS (though this idea isn’t new at all,

J Can be Readable

Written by AraneusAdoro

You must be kidding me! It’s like programming using regular expressions… You’ll never make me do that again! I’m looking at the code and feel like an idiot. Isn’t it really an esoteric language like brain fuck? Does anyone really use it? And such programs can be read afterwards? quicksort=: (($:@(<#[), (=#[), $:@(>#[)) ({~ ?@#)) ^: (1<#) Perl is a trifle against it. About J language J — is a Korean of programming languages (may look confusing). It’s an explosion in reserved characters factory. Plenty of brackets, periods, slashes and it even works. It must be magic or something. Wanting to be short or just having been carried away some people writing on J forget even simple rules of any code writing. These rules aren’t new but they acquire a critical meaning as applied to APL similar languages. As when reading ((]i.~[:{.[){([:{:[),]`([:<[$:[:>])@.([:32&=[:3!:0[:>]))«2 0 construction even a trained brain is at

Running and Software Development

Written by Michael Dubakov

What can running and software development have in common? Nothing special at fist glance. A sweaty and slender runner totally differs from a flabby, bent by scoliosis programmer. Stadiums don’t applaud to developers and no one gives them the country flag for the lap of honor round the office after some release. Nevertheless, running and development do have many things in common. I have read a very difficult book — Surfaces and Essences . Douglas Hofstadter had a blast and I didn’t want to read the book after the first 50 pages. I literally forced myself to read few dozens of pages per week until I read till the third book – then I loved it. This book is about the way people think. They think in terms of analogies. Using millions of examples, Hofstadter and Sander quite clearly bring out the way analogies work and the things you can

Qt 5.2, From a Sketch to Google Play

Written by xanm

Dear colleagues, I’ve been told about Qt 5.2 and its new feature of simple and quick creation of cross-platform applications for Android and iOS. I opened Qt website and watched a great video, in which Hello World application was developed for Android and iOS in 10 minutes. I was impressed. So I decided to take up mobile development. I had a plan of working my way up from a wish to develop an application to its publication in Google Play. At the same time I learnt about the famous Flappy Bird and that its developer had decided to delete his application. So I wanted to develop another copy of thus game. But my main goal, of course, was to try out new Qt facilities. C++ or Javascript? I like C++, but I didn’t dare to write such a small thing on it. C++ makes developer be very thoughtful and attentive

Using Go to Execute Commands on Hundreds of Servers with SSH

Written by youROCK

In this article we’re going to write a simple program on Go (100 lines), which will execute commands via SSH protocol on hundreds of servers, and will do it quite efficiently. It will be implemented with the help of go.crypto/ssh , which is SSH protocol implementation by authors of Go. More “advanced” version of the program written in this article is available on github: GoSSHa (Go SSH agent). Introduction The company I work for has more than one server and in order to keep the work efficient libpssh library on the basis of libssh2 has been written. This library was written on C with libevent use many years ago, and it still copes with its tasks. One thing is that it’s quite complicate to maintain it. Go language from Google is getting more popular, as well as within our company. So I decided to rewrite libpssh with Go and fix

JavaScript optimization challenge

Written by Няша Няшная

Hi, we're hosting the JS optimization challenge right now, with cash prizes and all. Link to full rules. The challenge: make JS strftime function very fast, and beat the performance of GNU libc's strftime . The slower code that can be used as a base for optimizations is here: github.com/mvasilkov/strftime You're free to use that source as the base of your solution. To make things interesting, we're not providing the reference benchmark. The benchmark will run on V8 (Node.js) engine. Send your solutions to [email protected] (as attachments, GitHub gists or whatever). Last date for submission is June 22, 2014. Winners will be announced on June 29.

Processes Paralleling to Speed up Computing and Tasks Execution in Linux

Written by XakepRU

Almost all PCs, released during the last few years, have had at least a dual core processor. So reader, if your PC isn’t extremely old or the bottom of the barrel budget brand, then most likely you are the owner of a multiple-processor system. Also if you like to play games, you should know you are utilizing potentially hundreds of GPU cores. But during the lion’s share of time all of these cores just gather dust. Let’s try to fix that. Introduction We rarely involve all the power of several processors (or cores) in order to solve every day problems. The high-end graphic engines are used for computer games only. I don’t like that. If I am working, why should my processors be resting? We should take on board all facilities and beauties of multi processors (multi cores) and parallelize everything possible. We should also use a heavy-duty video cards

Types Construction in Scala

Written by primetalk

When constructing “enterprise” systems it often turns out that ValueObjects (or case classes) are created. They store information about some instance of entity that is processed by the system. For example: case class Person(name: String, address: Address) This way of data representation in the system has two major strengths: Strictly typed access to the data; Capability of meta information binding to features with the help of annotations. And drawbacks: If there are many entities, the number of such classes also increases and their processing requires a lot of code of the same type (copy-paste); Meta information can be represented by annotations to the object features. But annotations facilities are limited and need reflection use; If the data should be represented not about all object features at once, it’s difficult to use the created classes; It’s also difficult to introduce a change of feature value (delta). We want to implement a framework that will allow creating new “classes” (types, types’ constructors, objects of the new types) incrementally using our own “bricks”. Using our own “bricks” production we can reach the

Introduction to Writing Tests with ScalaTest

Written by Kukuruku Hub

To be able to quickly start visualizing some of the tests that can be written with ScalaTest, we can take advantage of the test-patterns-scala template from the Typesafe Activator . It consists of a number of examples that essentially target the ScalaTest framework. The easiest way to get the code is to download the template bundle for test-patterns-scala. An archive contains a bootstrap script that can simplify our life's by starting Activator automatically. Setting up the test-patterns-scala activator project only requires you to go to the directory where you installed the Typesafe Activator and then, either start the GUI through the > activator ui command, or type > activator new to create a new project and select the appropriate template when prompted. Download the bundle Extract the downloaded zip file `cd` to test-patterns-scala directory from your console Run ./activator ui You can also generate the project by running: ./activator new

Mobile Typography

Written by Kukuruku Hub

As a designer you are probably keenly aware that more often than not, your dream font is not available on every device and every browser. Whether this knowledge is founded in the experience of designing and developing a site yourself, or from a horrifying experience such as your developer showing you the implementation of your design and feeling the special tug on your soul as part of you dies when viewing your original font choice rendered down into an abomination that makes comic-sans look vaguely desirable. Previously you may have even decided to give up the fight of using the perfect font for the entire site and opted to use it only on special portions of the design as an image. This, you tell yourself, will help you sleep at night and fix all the problems in the world as they can see the effort you have put into product

Transactional Memory: History and Development

Written by JIghtuse

Definition Parallel programming is difficult. When using systems with common memory, you can’t go without synchronization of parallel processes/threads access to the common resource (memory). The following are used for it: locks (mutex); lock-free algorithms (lockless); transactional memory. Transactional memory is a technology of concurrent threads synchronization. It simplifies the parallel programming by extracting instruction groups to atomic transactions. Concurrent threads operate paralleled till they start to modify the same memory chunk. For example, operations of nodes adding to the red/black tree (animation in the heading) can operate in parallel in several threads. /* Move item from one list to another */ int move(list *from, list *to) { __transaction_atomic { node *n = pop(from); push(to, n); } } Concurrency management approach with transactional memory use is called optimistic: we think that threads operate independently of one another and rarely change the same data. In this case most transactions are

N2O: Erlang Web Framework

Written by mag2000

Introduction This post implies a good intro into N2O . In order to learn about Erlang/OTP Web Framework N2O main features you should visit the github page or the official SynRC website . You will find there all the charts and presentations which you like so much. In this article I will cover the principles of framework operation. Version under consideration: N2O: 1.1.0. It’s always more interesting to see the result than to talk about it. I suggest that you install N2O to your PC first and then you will go deeply into its insides. It’s clearer that way. You can find answers to the arisen questions and recommendations at the official channel IRC #n2o at FreeNode.net. Installation Install Erlang if hasn’t been done yet. Download N2O, compile and run it. git clone git://github.com/5HT/n2o.git cd n2o/samples make && make console Look at: 127.0.0.1:8000/ Having opened a few windows you

Multitasking Management in the Operating System Kernel

Written by LifeV

As tasks share time on one processor kernel, I had to deal with multitasking management. Or rather pseudo-multitasking as tasks share time at one processor kernel. At first I’ll try to tell about the types of multitasking (cooperative and preemptive). Then I’ll move on to scheduling principles for the preemptive multitasking. The article is optimized for first-readers who want to understand how multitasking operates at the kernel level. But as everything will be accompanied with examples which can be compiled and run, it may interest the ones who are familiar with the theory, but have never “tasted” the scheduler. Introduction To begin with, let’s define what “multitasking” means. Here’s the definition from the Wikipedia: In computing, multitasking is a method where multiple tasks, also known as processes, are performed during the same period of time. The tasks share common processing resources, such as a CPU and main memory. In the