Catch up on stories from the past week (and beyond) at the Slashdot story archive


Forgot your password?
Back for a limited time - Get 15% off sitewide on Slashdot Deals with coupon code "BLACKFRIDAY" (some exclusions apply)". ×

Submission + - The four promises of Actor Based Programming for telco software (

neutrino38 writes: The Actor Model is a theoritical computation model which aims is to improve concurrent computing. In essence, Actors are 'processes' that can receive, process and send messages to other Actors. This is a computation model that is not based on shared memory and opposes the traditionnal shared memory, locking and multithreading model. In terms of hardware architecture, the multithreaded model aims at powerful servers few CPUs and shared memory whereas the actor model aims for concurrent processing on many computers cooperating through reliable networks links.

To my profane eyes, there are little theoritical differences between object model and actor model. But I am no academics and the intent here is to throw some practical views on the possible benefits that programmers can draw from actor based programming.

One has to admit that the original vision of many computers cooperating through networks did not materialize yet. The dominant model is a cloud of powerful cooperating servers providing online services to smart terminals through network. Multithreaded programming is the mainstream way of developping server side software.

However, there are some trends in computing that may be game changers. These are:
  • the 'cloud' or flexible computing where server-side applications are hosted on virtual machines Multiple 'instances' of the same application can be created on demand to cope with load surge. Context information is shared through add-ons such as memcached or databases. Advanced realtime web applications such as facebook use message and notifications and look like good candidate of actor based implementations.
  • the Internet of Thing where multiple devices with low processing power coordinates over a local area network and through the Internet. Again, this matches nicely with actor model purposes.
  • finally, server side applications such as HTTP servers are put under pressure by growing users bases. The 10K user problem well documented for web servers, occurs in any big server-side application. Adding more processors to cope with load does improve performance linearly as processes or threads spend more and more time to wait for locks when accessing critical ressources. The actor model provides a 'lock free' alternative that can overcome this issue.

Several programming frameworks and languages provides very good ways to implement actor based software. Three of them come in mind:

  • Erlang, a language developped by Ericsson and open sourced or Elixir that provides a friendlier language syntax but produce bytcode that is compatible with Erlang VM.
  • Scala a language that produces java compatible bytcode. It is used in the famous Minecraft game
  • The C++ Actor Framework brings the actor model into native code.

Erlang and Scala merge functional programming with actor model and that has a solid consequence: developpers can only assign variables once and cannot change the value. The only way to change a variable is to send a new messsage (or to call a function) with new arguments. This is a radical way to prevent any use of memory sharing but this breaks most of the classical programming techniques: loops needs to be implemented by recursive function calls or can be replaced with more functional equivalents.

Let's focus now on server side application development, especially in telecommunication field where protocol exchange is the main purpose. Intuitively the actor model fits perfectly . However the majority of telecommunication apps are still developped in classical C/C++ with scripting languages or in Java (SIP servlet). But Actors make four important promises:

  1. I shall not fail: Telco applications should always be on. With the OTP framework, Erlang provides a radical way to recover. If an actor detects an error condition, it can crash and be restarted. Dependant actors will be nicely notified about the restart. Application can partially crash and restart limiting the impact to a single user. Erlang also supports code replacement without application stop. I did not test it first hand but if proved, this is a tremendous advantage in telco business.
  2. I will not block: by design, actor model is lock free. This remove one of the worst nightmare of any server side application developpement.
  3. I can scale: actor model breaks downs a piece of software into a set of coordinated actors that do not share any memory. They exchange messages transparently and therefore can be very easily spread on several hardware system. Traditionnal approach implies communication context sharing that was never fully scalable.
  4. I am a finite state machine: That concept is not enough understood while it is central to build robust and resilient telecommunication applications. actor model is about exchanging message. The actor framework provides a natural way to map messages into function calls and implement FSM easily.

So ... why the telecom world is not rushing to embrace actor based programming ?

Its because it requires major cultural changes and telco world is a bit conservative.

  • Software needs to be entirely redesigned into actors that are simple and pipelined.
  • Developpers need to give up any use of shared memory to store a "communication context".
  • no more control on lock and threading
  • Langages such as Erlang and even C++ Actor framework uses a syntax that is so different from procedural approach that the learning curve is very steep. Almost hostile.

All this is much more radical than moving from init scripts to systemd on Linux. And this transition is costly: training developers, software redesign and reimplementation.

Is it worth it ? That is a question we are asking ourselves

Comment Apple example (Score 1) 202

I remember when apple rolled out iOS 8 and our web app broke (it was a simple form with buttons !)

Also when you are using advanced feature such as webrtc, then you have to block users for loading the page with Safari or Internet Explorer. I am sorry but while on paper HTML5 is the best approach, it does not yet offer the uniform API an behavior that web developper need to save time and money.

Comment I agree except on the development time will decrea (Score 2) 202

I am all for HTML5 improved support and standard but our experence with various HTML5 implementation is that developpers actually spend a LOT of time accomodating the differences between browsers and browser versions.

Not only between mobile and desktop but between different browsers and different version of the SAME browser.

Different implementations of the same standards are almost always breaking the code.

So on the contrary using HTML5 increases the development time and maintenance cost as web sites or web apps have to be "corrected" to follow browser support or interpretation of HTML5.

In comparison, such maintenance for flash applications is close to nil even flash was upgraded from version 5 to version 11.

However, I agree that flash beiing proprietary, it is not the way to go now.

User Journal

Journal Journal: Bouddhisme engagé et actions justes - partie 1 - pourquoi agir ?

Préambule : tout ce qui suit ne peut pas être considéré comme enseignement. Il s'agit simplement de réflexions personelles sur la vie en générale et sur ma compréhension limitée du Dharma. Je suis un simple pratiquant et je m'excuse par avance des erreurs et imprécisions qui pourraient figurer dans ce texte.

Submission + - ATOS Healthcare seeks early contract termination in the UK (

neutrino38 writes: ATOS Healthcare, subsidiary from the French service company ATOS has won a contract with UK govt in 2010. Atos Healthcare conducts assessments on behalf of the Department for Work and Pensions. Basically it implements David Cameron policy on social services fraud management.

It became so impopular that its employees are routinely insulted and threathened on social networks (about 153 threats a month according to the article). The company is now looking for a way out before the planned end of the contract in 2015.

Therry Breton, its CEO has declared that : "In its current form, the system does not work neither for the beneficiaries, nor for the DWP nor for ATOS Healthcare".

Submission + - LXC 1.0 has been released (

An anonymous reader writes: After 10 months of development, the Linux container management tool LXC has released its "production ready" 1.0 version. LXC is a set of userspace tools and libraries using the kernel namespaces and other security features to run a full Linux system in a "container".

It is similar to OpenVZ, Linux-Vserver, ... but doesn't require any kernel patches, instead using only features that have been merged into the mainline Linux kernel.

Highlights for this major release include a stable API with bindings for Go, Lua, Python3 and Ruby, support for entirely unprivileged containers (using the fairly new user namespaces), support for a handful of backingstores, a reworked set of tools and improved documentation.

Comment Break down your algorithm (Score 4, Informative) 365


It is probable that you can break down your algorithm -(I do not mean code) into a pipeline of elementary processing and find implementations (IP) for each of them.

to give out an estimate:
- subdivise your algorithm into simpler pieces
- find for each simple piece how it can or could be implemented in hardware and the complexity of each piece.
- do the sum.

  Indeed an hardware designer or consultant would be of a great help here.

Comment The press knows how to run Microsoft ... good ! (Score 1) 355

Hey its AMAZING to see so many people in the tech press that know exactly how to run microsoft. I thought that CEO of this kind of giant company were pretty difficult to find. Its a relief to see that there are plenty of candidate for the position ...

Seriously, in a perfect world, I would force such people to open a successfull bakery before being granted the right to send 'advises' to entrepreneurs or company bosses.

Comment Fed up with google "standards" (Score 0, Flamebait) 97

Here we are again.

After VP8, protocol buffer, Google is a it again providing some free replacement of some existing standard (DTLS here

But of course, Google's people know better and have more money. And the list can go on. Dart as a replacement of javascript. Protocol buffer as replacement of ASN.1, SPDY to replace HTTP. With Jingle google tried to replace SIP protocol as well but at least the extended an existing standard but they dropped the support when stopping Google talk. For couse everyting is free, open source and Not Evil. So why bother?

Well as an aging network engineer, I am starting to be fed up with such "innovations". More consensus building would be refreshing.


Submission + - British Government Tries To Kill EU Privacy Regulation (

judgecorp writes: "The British Government has joined corporations such as Yahoo, Facebook and BT, in arguing against a tough proposed EU Regulation on Privacy. The UK government's intervention, led by justice minister Lord McNally, wants to scrap the proposed Regulation and replace it with a system of Directives. That's not just a matter of word play, it dilutes the proposals greatly. Regulations must be implemented in all EU member states at once, while the states have freedom on when and how to put a Directive into force."

Submission + - Free coding school for geeks ande develoopers founded in Paris and called "42" (

neutrino38 writes: Xavier Niel, founder and CEO of the ISP Free Telecom, well known in France to be an agressive competitor of the big incumbent telcos like Orange, called a press event to explains a new mysterious intiative called "born2code".

It appeared to be the launch of a new computer programming school, based in Paris, codenamed "42" in reference to Douglas Adams books. The cursus is quite revolutonary in regards of the traditional French education system:

- the admission requires no prior background, only to pass the selection tests (and age limit from 18 to 30).
- the selection tests are in two phases: first tests are online. It will preselect 4000 candidates. The second tests need the people to come and be involved in actual intensive programming tasks (15 hrs / day) during one month in a dedicated room called "the pool". Out of this will 1000 student be selected.
- once admitted in the school, no tuition fee will be required nor any future contribution as a professional.
- the school will not deliver any diploma. Mr Niel argues that companies are hiring on skill and experience basis rather than on diploma (note: french HR are badly addicted to Diplomas)

Mr Niel blasted the traditionnal education systems saying it produces "standard engineers" that are not innovative and that existing private schools are too expensive and prevent real talents to emerge by selecting student over money. It also reject traditionnal education in favor of a 2.0 education, peer to peer and project centered education that are in line with today's connected society

The goal of this school is to train 1000 "genius" every year. The proclamed purpose is to help IT companies to find suitable people for innovation, helping in this way the country competitivness.

Mr Niel will be funding the school on its own money during 10 years by putting 50 M euros on the table. Hehopes that other IT companies will take over as he is conviced that "only private initiative" can bring this kind of renewal.

The school is due to open next fall and be equipped with brand new 27 inches iMacs.

Submission + - Comparison Between Responsive Design and Mobile Sites (

Yuri Bril writes: "The days of a fixed-width 960-pixel-wide web design are behind us. The markets for smart phones, tablet devices, and personal computers have created and environment where websites need to function on vastly different screen sizes and form factors. Desktop monitors can be over 2,000 pixels wide, while some phones are less than 400 pixels.

Read more:"


Submission + - Mozilla Firefox Patch Deals with Third Party Cookies, Smartly ( 1

hypnosec writes: Mozilla is testing a new patch for its Firefox browser that would provide more privacy to users and control over third party cookies by targeting the manner in which they are installed on users’ systems. Currently when users visit a website that site may be calling up a number of things from other websites – be it advertising, analytics, behavior tracking, etc. These third party elements drop cookies onto users’ machines, which may be accessed at a later date or time to gather data about users' usage habits. The new mechanism effectively prohibits websites from installing third party cookies onto users’ systems. Users who have the patch installed will have to directly interact with the website or the company "for a cookie to be installed on their machine." This means that up until a user actively interacts with the third party website directly, Firefox will not allow for those cookies to be installed on the user’s system.

Nobody said computers were going to be polite.