Atop, when you need to know exactly what's happening at the system-resource level

System resources are always limited, no matter what type of computer or server you're using. You never seem to have enough RAM, CPU threads, or disk I/O. High level tools like top, htop,sar, iostat, or vmstat do help, but they only give you the 10,000 foot overview of resource usage. They don't allow you to see what part of which program or process is eating up too much RAM or which part is creating race conditions on lock files.

A much more powerful took is "Atop", a powerful monitor program that allows you to see system-level counters concerning utilization of CPU and memory/swap, as well as see disk I/O and network utilization counters at the system level -- in real time or historically. It also allows you to store raw counters in a file for long-term analysis on system levels and process levels, as well as seeing resource consumption for each thread within a process of a multi-processor program.

Sounds exciting? Read on.

Interview with Mikeal Rogers: Node.js fork that ended up as a giant, unifying step forward

Thu, 2015-06-18 04:43 -- admin

Node.js is the software that allows you to run Javascript to create amazingly powerful server-side applications by using Google's V8 Javascript Engine. As a Node developer myself, I have always felt frustrated by seeing that Joyent, the company behind Node.s, was extremely conservative in terms of upgrading node to use the latest V8 version; the project was also struggling to get developers to actually contribute to code. This is why Fedor Indutny did the unthinkable: forked node and created IO.js. Today, the two projects are uniting possibly offering developers the best of both worlds.

How to protect your GNU/Linux computer from remote attacks with Fail2ban

Governments around the world are hacking into any computer that they can find. They are not just targeting large companies, but any computer that has information that they can sell. Is there anything on your computer that some hacker could sell for money? When was the last time you looked at your /var/log/auth.log file?

It's 2015, writing a simple 6 screen application is still too hard

Last night I saw a message from a friend of mine in Facebook: she is trying to organise a baby sitting community where people who trust each other will exchange "tokens" when they babysit each other's children. My first reaction was something I just couldn't resist: I drew up a normalised bunch of tables (6, to be precise) which will organise carers, children homes, and bookings. I even wrote the server side part of the story as a bunch of REST calls (it took me 2 hours in total). Then... I realised that giving an interface to my data was way, way harder than it should be.

The simple guide to bitcoins using Electrum

Bitcoin is the most established digital currency available today. It provides a safe, anonymous way to send and receive a virtual currency everybody trusts. However, managing bitcoins is not quite as simple as managing a bank account. In this article I will explain how to manage your bitcoins using Electrum. Please note that in this article I will provide working knowledge of how to use Electrum, without entering the mysterious land of cryptography and technical details of Bitcoin.

Secret Maryo Chronicles: a wonderful GNU/Linux game

For those people who grew up on the "classic", 2D version of Super Mario, and -- why not -- those who like simple, but very refined games, Secret Maryo Chronicles is not to be missed. Mind you, it's not Mario, but Maryo; however, it's just as much fun.

If you are familiar with Super Mario, you will find right at home here: you will find turtles, mushrooms, nasty plants, pipes, and many other elements that are typical of this classic game.

The game is released under the GPL v.3; so, it's fully free for you to download, play, and -- why not -- change, also thanks to the built-in world editor.

Create an encrypted disk image in GNU/Linux

In my previous article about creating a "mountable" disk image in GNU/Linux, I explained how to create a file that effectively mimics the functionality of a disk: I explained how to create a file which will then be used, in turn, to contain directories and files. In this article I will explain how to make the next natural step: encrypt that file.

Why we need anonymity on the Internet -- even if it hurts

I have recently restarted Free Software Magazine, after working full time on a free software project. One of my articles ended up on Slashdot. In the past, this meant hours of frantic work: on one hand, being "slashdotted" meant dealing with a huge influx of traffic which normally brought our server to its knees; on the other hand, it meant discussing the article with very intelligent people. I didn't expect what followed this time: I was the target of what I assume to be a couple of well spoken millennials who carried out a grating, personal attack against me.

Netflix: the crumbling borders of geolocation and the thieves who happily pay for what they "steal"

One upon a time, movies were released in different countries at different times. This could be done because there was no easy way to copy and store away a movie. If you lived in Italy, you could wait up to two years before you saw a popular movie. Then two things happened: it became easy to copy and store movies; and everybody in the world suddenly became interconnected. The regional segregation ended: the only ones to believe that it's still there are the dinosaurs from a past era.

Opening large PDF files in GNU/Linux: muPDF comes to the rescue

I was recently given an ebook by a friend. It was a photography book, with tons of hi-res images and very little text. When I opened it with Ubuntu, Evince (the default PDF viewer that comes with Ubuntu) gave in: after a few pages, it slowed to a crawl. I did a bit of research, and found the program that rescued my viewing needs: MuPDF. The good news was that I could finally read my book. The bad news was that I found out that the company behind it has in the past misunderstood the terms of the GPL and started a (later withdrawn) litigation against Palm.

Ubuntu Software Center: proprietary and free software mixed in a confusing UI

I have been watching the evolution of the Ubuntu Software Center for quite a while now. I had doubts about its interface and its speed, but I liked the fact that it offered an easy, down-to-earth interface that allowed users to install software easily.

However, I have to say that the way the Ubuntu Software Center has evolved is worrying me -- a lot.

Watch Netflix outside the US, for nearly free (without paying for a tunnel)

Some services line Netflix have an annoying geolocation restriction that made them unavailable outside the United States. In case of Netflix, this is due to licensing issues. It's not a slim difference: do you want to be able to access just over one thousand movies, or would you prefer to have access to over thirteen thousand movies?

Simple Photo Manipulation in GNU/Linux with Fotoxx

Image manipulation in GNU/Linux has always been associated with The Gimp. However, most users will find Gimp vastly oversized for their needs. Fotoxx is a neat, simple and yet very advanced photo manipulation software that is definitely worth installing and playing with.

The rebirth of Free Software Magazine

When I started Free Software Magazine, over 10 years ago, it was a very different world. Magazines still mattered, Facebook was a primitive site for university students, Digg was about to become a huge new site (before disappearing a few years later), and... did I mention that Magazines still mattered?

"Lunatics!" is back - Crowd-funding, Free-culture, and Free-Software

After an additional year of production work, our free-film project "Lunatics!" is back up on Kickstarter. We have a lot more done - some "finished" animation, voice acting and soundtrack mixing, a lot more completed 3D models, including some of the toughest mech modeling, and several characters. We are still 100% free-culture, using CC By-SA license for everything we release, and we're still open-source, making our models and other elements available to the commons. We use only music with By-SA compatible licenses, and we are working entirely with free-software, especially Blender, Kdenlive, and Audacity.

Finding changes in a sorted list: a trick

Think of a phone directory listing with a lot of Browns followed by some Brownes, Brownings and Brownleys. Is there a simple way to identify the places in the sorted list where Brown changes to Browne, Browne to Browning and Browning to Brownley?

If you're a programmer, you've probably just thought of an 'if, then' test for items in the list. If you're an AWK-lover (like me!) you may have started thinking about the getline option.

There's another and more interesting way to do this job on the GNU/Linux command line, as explained below.

The Googlisation of Surveillance: The UK Communications Data Bill

There is a belief that democracies respect the rights of their citizens. Well, they don't. There is a great deal of cant written about that but even the democratic modern state has become so big, so intrusive and utterly overbearing that its cancerous tentacles have insinuated themselves into every orifice of the body politic. No sooner has one threat to personal and internet freedom receded than another springs up like proverbial dragon's teeth. One of Hecate's children of the night has been brewing for a while and is set to make its way onto the statute book here in the UK.

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