Links to articles not necessarily written today, but still interesting.
Reconsider: “Part of the problem seems to be that nobody these days is content to merely put their dent in the universe. No, they have to fucking own the universe.“. Nice read on startups, VC, investors and the overall “startup philosophy”.
I already handle the API resource definitions in nginx, and I only need to override the root maintenance definition. In addition, the JSON response should also have the correct Content-Type header set.
In this case, is probably “easier done than said”, and is all done in here:
I enjoy doing these occasional reviews: it’s a good excuse to read a new book, learn something new (there’s always something to learn, every day) and to move my eyes aways from a light emitting digital device (yeah, apart from when I actually write the review…). And since I fully read the books, that’s why usually it takes some time to review them all.
I have to admit I love NoStarch books: lovely cover arts, a nice book form factor, well written and edited content, multiple formats to choose from (paper, digital DRM-free versions). And “How Linux Works” is no less.
The Review: How Linux Works by Brian Ward
17 chapters strong, the book opens with a general overview of a Linux system providing the reader with a really clean explanation of the differences between the kernel space and the user space, moving to a quick overview of the shell system.
From Chapter 3, the pace changes, and it’s here where the author starts diving into into the real Linux system. Devices, device types, sysfs and how they are implemented at the kernel level are an introduction to concepts that will be taken further in Chapter 4, where file systems, a generic overview on how they fit into the kernel, and the most used and common commands to work with partitions, are introduced.
I consider Chapter 5 and Chapter 6 to be the strength of the book: how the Linux boot process works, what GRUB is, does and how to configure it, all clearly explained with detailed steps of the overall boot process. And then, as a natural consequence after the boot phase, the init systems are introduced and the reader is taken further into the user space land.
Chapter 6 covers basically everything that is needed nowadays to understand the init process: systemd, upstart and sys-v are all explained in their glory details (although the latter is the less detailed): how they are configured, where their configurations are located and the different terminologies each adopts are easy to understand.
From here on, the book covers all that is necessary: logging, users, /etc and login methods with a focus on PAM (Chapter 7); processes, resources, CPU & I/O and all the commands to help you in performance diagnosis (Chapter 8); network, network configuration, a concise but exhaustive introduction to the network layers, the kernel routing table and internet/network user space applications (Chapter 9, 10).
Chapter 11 takes us back to the shell with an extensive coverage of its most useful and used commands, that will lead as to know all the file sharing programs available at our fingertips (Chapter 12).
The remaining chapters cover the user space environment: startup files, desktop environment and window manager, D-Bus, CUPS; development tools (compilers, debuggers) and how to compile software.
Of all the book, I found these last chapters (counting also Chapter 12) to be the less interesting: probably because most of the concepts described were already known, or they were covering not (that) much interesting subjects to me.
In the End…
The book is really well organized, technically accurate and up-to-date with the recent modern Linux technologies. A really great Linux power-user book that doesn’t spend too much time in a graphical environment, but concentrates on command line tools and the depths of how a Linux system is glued together. Read it if you want to expand and deepen your Linux knowledge.
Let’s start with with clearing out the confusion the term “hwpack” has in this context.
Generally speaking, for Linaro Image Tools an hwpack is a tar-ball that contains Debian packages, some configuration and metadata files, and some directory structures, needed to create and install bootable operating system images.
Linaro Image Tools has had support for this kind hwpack since the beginning of time, but they are not necessary to create Android bootable images. The process to create an Android image is slightly different.
This new hwpack, the Android hwpack, is just a configuration file, based on the same syntax of previous Linaro Image Tools hwpack, that stores information necessary to correctly create Android images. An Android hwpack does not contain any Debian packages nor binary blob or anything else, it is just a text file (a YAML file for instance).
It’s probably better to call is “Android configuration file“.
Why an Android hwpack
The necessity for this came out during last Linaro Connect Europe, from the Android team. The needs were an easy way to add support for new boards (without having to hack into Linaro Image Tools code), the possibility to change board parameters (almost) “on-the-fly” for testing (without having to touch code), and the possibility to maintain backward compatibility by providing some kind of “versioned” hwpack, guaranteed to work for specific Linaro releases.
How to use it
In order to use it, you need to have at least Linaro Image Tools version 2013.01. At the time of this writing, Android hwpack support is also being built into the Android boot tarball, so it should be totally transparent for the user: no need to add command line arguments and to pass file paths.
Still, it is possible to pass an Android hwpack to Linaro Android Media Create, the command line tools that creates Android bootable images. The command line argument is the same as Linaro Media Create one: –hwpack
So, if you want to use the new feature, arm yourself with an Android hwpack file (examples can be found on GitHub), and run:
This is that kind of post that are more necessary to me for remembering than anything else. Lots of digital ink has already been spent on this topic, but, as others I guess, I find that writing down things helps me remembering them (and mind-maps are precious on that front).
VirtualBox Clone Operation
I have a couple of local virtual machines installation for Ubuntu desktop and Ubuntu server, usually the latest LTS ones, and I clone them as I needed: I need to test some scripts, or the installation of a program, like it was being performed on a real installation.
VirtualBox has this nice little feature of creating clones of your virtual machines, and in no time you are up an running with a clean environment (as long as you remembered to take a snapshots at a good point in time).
When you clone a virtual machine, you are cloning everything of it, configurations included. And that’s where the problem is. The network will not work at all, and ifconfig will tell you that there is no interface configured.
The solutions lies in one file:
Open that file with your editor, remove the offending line and reboot.
In this case the offending line is an erroneous “eth*” interface, that will results in multiple network entries in that file when just one is needed. Pay attention to the MAC address of the network interface though.
This is my first attempt at writing a book review, so bare with me if it is not the best around. And here the “usual” disclaimer: I received a free copy of “Think Like a Programmer” from NoStarch Press.
The book: Think Like a Programmer an Itroduction to Creative Problem Solving
As the titles goes, this is not only a book about programming or development, it is an exercise on problem solving and thinking. The book has one of the best starts I could imagine: puzzles. Funny puzzles, those that nowadays scare candidates during the hiring processes at big companies.
The puzzle-pace is kept for the first two chapters, and the author guides you into well detailed examples of problem solving: how to break a problem into smaller parts, how to apply your knowledge to unknown problems, where and how to recognize patterns.
After these two introductory chapters, things start to get serious. Complex concepts are introduced: arrays, pointers, classes, dynamic memory… and the problems accompanying them resemble real-life ones. To fully grok these sections, a good knowledge of C++ is needed. The author introduces each new topic with the basic needed coding knowledges, but if you do not have any previous C or C++ skills at all, the examples and the exercises might be daunting.
The book is broken into 8 chapters and you can perceive the complexity increasing up to a peak in the middle ones. The last two chapters are less demanding and the concepts introduced are not tied to any particular programming language: they step into the realm of software engineering, code reuse and something I would refer to as task management.
In the End…
It is not meant to be a cookbook, nor something you can use as a reference manual. You have to embark yourself , and let the author sail you through a journey of discoveries, learning and problem solving, being patient and going through the proposed exercises. It is a training for your brain, for your code writing-fu, and mostly for how to approach problems and how to tackle them.
Being overwhelmed by passwords, for all the disparate websites you have to login to, plus trying to keep safe password for personal and work activities without sharing the same ones, was starting to get harder. Too many websites, to much passwords.
The Last Password to Remember
As a colleague of mine suggested, I tried out LastPass. A nicely done online services that offers you the possibility to have a secure password vault where to store your passwords and identities. LastPass integrates also with your browser and helps you:
Filling out forms: you can store all your credentials and credit card info too
Logging into the stored web sites, also automatically if you tell it so
Creating one time and secure passwords
Updating the passwords when it detects you are changing them
And lots more…
You can even use it with a YubiKey and with Google Autheticator for a two-factors authentication, and it also has a “security challenge” where it tells you if any of your accounts were compromised or how strong are your passwords. The service is really well done and provides you with a smooth experience (even if the graphical web interface is not the best around).
But it is not open source. This is the kind of service I would like to have as a truly open source project. Are there any open source project like this out there?
Almost six months ago I started working for Linaro, from home. It was the first time for me with a home-based job, and I’m enjoying every minutes of it.
Before joining Linaro I did my fairly amount of researches on the Internet about how to organize your workday and also your life: try to do as if you had to get ready for office, eat & drink, do not always stand sit…
I didn’t change much of my usual habits, and I’m trying to keep home and work activities as much as possible separate from each other. Sometimes they will interfere, but I guess it is normal, as long as you remember to stick to your plan of separating them.
So, this is something I would call my usual day…
Getting Out of Bed
I’m an “early bird” as to speak.
I like getting up early in the morning. Luckily from where we live, opening the window we can see the sea and the sun rising. Getting out of bed is not that bad after all.
During the warmer months I also enjoy going out jogging for 40 minutes, during the colder months I usually start my days with a 30-40 minutes training. Nothing much heart-pumping, and everything weight-free, just free body weight: abs, squat, push-ups, and lots of stretching (sometimes even yoga, but my yoga-skills are really rudimentary). On the Internet you can find plenty of videos and web-sites on how to train in the correct way and for how much, so you still get to vary your training (I still haven’t found a really good Android app for something I would call zen-training: a mix of body and mind exercises, that doesn’t get much into the way, and that suggests you exercises).
Shower, that helps me like a caffeine shot (I do not drink coffee, even if I drink tea), and a big breakfast. Breakfast that for me is the most important meal of the day.
No computer or any electronic gadgets activities until after breakfast.
The Work Day
I sit in front of the PC around 8-8.30, checking emails, reading newspapers and the usual social websites. At 9, my (virtual) pomodoro clock usually starts ticking. I try to organize my working days in that way, sticking to the pomodoro technique as much as possible, and having pomodoro times also for checking IRC and other work related activities I have to do online.
Code, Eat & Drink
I always have something to drink next to my keyboard. Sometimes it even gets on my keyboard, but that’s another story…
Tea in the morning, that usually propels me almost close to lunch time, then water. I do not eat anything else in the morning, and in the afternoon sometimes I have a little break and usually I eat a fruit. At lunch time, I cook: I enjoy cooking, and it is one activity that me and my girlfriend enjoy doing in the evening together. It is a good moment for talking, and for preparing food.
Getting Into Bed Again
After dinner, we spend time on the couch watching movies, or doing our open-source-communities related activities. I also enjoy doing a 10-15 minutes streching/yoga session before getting into bed again. And before falling asleep, I always read a good book.
As in all rules that you set for yourself, form time to time I do not follow them, without feeling guilty. I need the liberty of doing what I like to do, with the confidence of getting back to my habits.
Yesterday, for a work task, I needed to convert a bazaar repository into a git one, to store code for other teams (that mostly use git) to work on. The bazaar repo was very simple actually, small history and it didn’t contain any merges.
Read The Docs™
Or almost… The first thing I did was heading other bazaar extensive documentation, in particular to its wiki sections on plugins. And there you have it, just an install-command away, ready to work: bzr-fastimport. Yeah, it says import, but it works also on the export part.
During the Christmas holidays I spent some time “refurbishing” a netbook me and my girlfriend have, but is not used, into an home-made media center, running (at the moment) plain Ubuntu 12.10.
We watch some TV, during and after dinner, mostly for TV series and movies, and we used to do that loading everything on a USB key attached to the TV. A boring, and repetitive task. So why not giving some new life to that small netbook?
All the ingredients for this recipe are:
A netbook (this one has an Atom N570 CPU, 1GB RAM, 500GB disk)
Installing the operating system, the necessaries codecs and all the updates is an easy-peasy experience nowadays. Nothing special to report, everything works flawlessly. After connecting all the cables, safely hidden from the eye (the back of the TV is turning into a jungle), the netbook-turned-media-center is now stored in a shady place in the living room, connected to the TV via its VGA cable (unfortunately the only video output), linked to the Hi-Fi via Bluetooth (hurray! one cable less!), with close to 2TB of USB-connected disk space, sharing videos and music on the internal network.
At the moment I’m piloting the media center via a VNC connection from a Nexus 7, but I’m planning to find a (or write my own) keyboard and mouse app for the tablet to pair up via Bluetooth with the netbook. Or a special Ubuntu oriented Android app to control an Ubuntu machine in an easy way.
I tried installing Rygel to serve media files, but had no luck in making it work. I will have to dig deeper and give it another try. The other solution I was pondering was to install XMBC. Time permitting, I’ll probably try it out.
Of course everything is not perfect: I have some high quality videos, Matroska files weighing from 2 to 8 GB, that the system is not handling in a good way. The smallest ones are not reproduced correctly, audio and video are out of sync, the biggest ones are not reproduced at all: or you get video, or you get audio. Guess the decoding is not that fast to handle everything is a smooth way. Listening to music via the Bluetooth connection to the Hi-Fi, is not as bad as I would have thought: it actually provides a really enjoyable experience.