Mentoring Eudyptula Challenge - 1

This post and coming is intended to help of getting things easier on Kernel challenges, The Eudyptula Challenge.

But it will not give you the total solution, [however, you can find those by googling] but will try to help you how you can understand the problems and get the things easier.

Well now - the Eudyptula challenge is a list of tasks to learn linux kernel, its structure and development processes. Mainly its a bot, supplying and evaluating your tasks.

The first requirement to participate the challenge is to learn emailing as plain-text. Those who are well known of using sendmail from command line do know it by heart. But for modern young guys - you better use thunderbird, and set its settings as unchecked Compose message as HTML format.

On other hand, if you are using gmail on web by selecting Plain Text Mode while composing your email would give you same benefit.

Infrared Transmitter Sensor Driver for Raspbery pi

37 sensor kit box is shipped with a Infrared Transmitter sensor. Alike Line Tracking Sensor, this one also a single pin sensor, turned on infrared while got ON / High on Signal port.

Hardware Description :

The IRT sensor circuit is very simple, just consist of a Infrared LED. The sensor got 3 physical PIN, and only Signal marked as S. Well, the middle on is for Volt [5v], and last one is for GND.

S is connected to GPIO – 2.

Line Tracking Sensor Driver for Raspberry Pi

KY-033 is a line tracking sensor. This project is to develop a dynamically loadable device driver for sensor KY-033 to enabled in RaspberryPi -1.

KY-033 is a single pin line tracking sensor. 

Raspberry Pi -1, a very popular SBC running with Debian linux (code name Wheezy for raspberry pi) with default kernel version 3.18. 

As it required to develop a kernel module, same version of running kernel header should be installed and configured for the system.

Description of Hardware:

The traget sensor KY-033 is a Line Tracking Sensor consist of one Infrared light and one LED. It also consist of a Si photosensor. The basic principle of Line Tracking Sensor is to detect if any white light component reflect from opposite surface.

Precision Time Measurement to read Remote Sensor

A scenario is like this --

You got a task to figure precise round trip time of a remote device or perhaps, need to measure how much time it required to receive the sensor data at requested side.

To measure accurate round trip time from client to sensor, two different technique is mainly popular. 

First, used timespec struct (sec & nano-sec) with CLOCK_MONOTONIC marco of kernel to measure time between sending client request and receive of result from server. 

Second, fill timespec struct (sec and nano-sec) variable with network driver packet timestamp macro SIOCGSTAMPNS for sending socket and receiving socket and calculate the difference.

Example Output =>

 SHELL>$ ./pngclnt_v2 192.168.178.100  
 0.000000s : 0.019165 sec  
 Output 1  
 0.000000s : 0.020459sec  
 Output 0  
 0.000000s : 0.019314sec  
 Output 1  

The idea is client -- server scenario, which means a server will run on sensor side and wait for client will request. Once receive the request, server script will perform the task and respond back to client.

Raspberry pi - prepare for Kernel Space Programming

Raspberry pi is one of the most popular SBC in market with ARM processor. It is very popular among students for playing as embedded stuff.

There are few points, need to noted down, while working or playing with Raspberry pi.

1. SDCard shows 56 MB, while I've 4 / 8 / 16 GB etc.

The reason, windows cannot read the actual size of SDCard is, its reading only the boot partition. To get rid of this problem, its advised to use SDFormatter.

2. Which image to Install ?

Default Raspberry pi gives two type of installation image.
        1. NOOB -- completely for beginner. I'd say for those who have no / less knowledge about linux.

        2. Raspbian -- A good place to start learning with Raspberry pi. Usually WHEEZY image is popular as starting. If you've smaller SDCard, and no requirement of Desktop, you may choose Jessie Lite minimum version.

ERROR - vSphere Client could not connect.

if you are running ESXi 5 / 5.5 [ I've experience only these two], you probably experience error as below image, with error message -

" vSphere Client could not connect to "XX.XX.XX.XX". An unknown connection error occurred. (The client could not send a complete request to the server. (The underlying connection was closed: An unexpected error occurred on a send.)) "

Hadoop changes on Single-Node Cluster Installations

There are many notes about HADOOP single node cluster installation, mostly in Ubuntu machine. All of them I've seen worked. But as time passed by, hadoop developer also made some structural and logical changes to fit the application better.

Here I wish to sum-up those changes (e.g. change of conf, file structure etc.) so newer user would get required commands or files easily while doing HADOOP signe node installation.


first to download hadoop =>
---------------------------------------------------
Best option is to search for nearest repository for hadoop from -

http://www.apache.org/dyn/closer.cgi/hadoop/common/

for me, below is the nearest

$ wget http://apache.lauf-forum.at/hadoop/common/hadoop-2.6.2/hadoop-2.6.2.tar.gz