Somphol's Tech Talk: November 2014

Friday, November 21, 2014

Interesting recordings on Youtube

PyCon 2014, https://www.youtube.com/channel/UCFDHJGm0IxH9uwcIHfR72yg
, https://www.youtube.com/channel/UCZN5ow2fjnk8-X5GCp_IbYQ

Startup class @ Stanford

It is hard to follow at tech news without coming across some of these.

So, just another bookmark!

How LinkedIn's Reid Hoffman taught Stanford students to build billion-dollar businesses through personal networks (in 4 quotes), http://venturebeat.com/2014/11/06/how-linkedins-reid-hoffman-taught-stanford-students-to-build-billion-dollar-businesses-through-personal-networks-in-4-quotes/

How to Start a Startup, https://www.youtube.com/channel/UCxIJaCMEptJjxmmQgGFsnCg

http://hearstartup.com/

http://startupclass.samaltman.com/

Walking past Expert Beginner stage

I think I have seen that word before when reading through Michael O Church’s The trajectory of a software engineer… and where it all goes wrong, http://michaelochurch.wordpress.com/2012/01/26/the-trajectory-of-a-software-engineer-and-where-it-all-goes-wrong/

A post on Quora link me to Erik Dietrich’s “Expert Beginner” series, which I haven’t explored yet. I am quite like the word so I will definitely catch up with the writings.

How Developers Stop Learning: Rise of the Expert Beginner, http://www.daedtech.com/how-developers-stop-learning-rise-of-the-expert-beginner
How Software Groups Rot: Legacy of the Expert Beginner, http://www.daedtech.com/how-software-groups-rot-legacy-of-the-expert-beginner
How Stagnation is Justified: Language of the Expert Beginner, http://www.daedtech.com/how-stagnation-is-justified-language-of-the-expert-beginner

Not quite directly relevant, but an article “The Programmer’s Price” is also quite an interesting read, http://www.newyorker.com/magazine/2014/11/24/programmers-price

And, Teach Yourself Programming In Ten Years by Peter Norvig is also related, http://norvig.com/21-days.html.

Thursday, November 20, 2014

Stand-alone NTP Server without Internet access

If you ever want to have an NTP server in environment where there is no internet access, you can run ntp server on Linux with the following configuration.

# sudo vi /etc/ntp.conf

……server 127.127.1.1fudge 127.127.1.1 stratum 12……

REF: https://wiki.archlinux.org/index.php/Network_Time_Protocol_daemon

# sudo /etc/init.d/ntp restart

Run ntpq to check the local stratum level. (You can change it to any other level, it doesn’t have to be 12 as shown above)

# sudo ntpd –q

You will also have to adjust the ACL using “restrict” configuration. (In this case, allow NTP server to be accessible from 192.168.1.0/24)

# sudo vi /etc/ntp.conf
restrict 192.168.1.0/24

Another Ref: https://help.ubuntu.com/lts/serverguide/NTP.html

On "Introduction to Algorithms"

Algorithms seems to be quite a mainstream discussion topic lately.

In the past week, I found no less than 4 posts relevant to this book “Introduction to Algorithms” from different sources.

http://en.wikipedia.org/wiki/Introduction_to_Algorithms

And since in general it is all about programming and coding, I think I will just put those relevant links together for later read.

Why did CLRS decide to co-author the Introduction to Algorithms? How long did it take from the beginning to the end?, http://www.quora.com/Why-did-CLRS-decide-to-coauthor-the-Introduction-to-Algorithms-How-long-did-it-take-from-the-beginning-to-the-end/answer/Thomas-Cormen-1

THE PROGRAMMER’S PRICE, http://www.newyorker.com/magazine/2014/11/24/programmers-price

Khan Academy’s Algorithms section, https://www.khanacademy.org/computing/computer-science/algorithms

There is also another piece of news about “Introduction to Algorithms” book’s co-author turn to crowd sourcing for input on what to be included/excluded in the next edition. I couldn’t recall where I read it from but the quora thread in question is here http://www.quora.com/As-we-start-planning-the-next-edition-of-Introduction-to-Algorithms-CLRS-what-should-we-add-and-what-should-we-remove

Installing Java JDK on Ubuntu

I am working on getting vert.x (http://vertx.io/) to run in a lab environment as part of my end-to-end troubleshooting effort. The binary version of vert.x requires JDK to run.

Therefore, I found myself in need to having a working JDK install on my fresh Ubuntu Server 14.0.4.1.

I found a good instruction set here - http://stackoverflow.com/questions/16263556/installing-java-7-on-ubuntu.

Essentially, I run these commands. (Detail manual configuration can be done, but I love this short and simple method)

sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java7-installer
sudo apt-get install oracle-java7-set-default

sudo apt-get install oracle-java7-installer

sudo apt-get install oracle-java7-set-default

Initially I have a problem with ‘add-apt-repository’ command not found, but the solution is outlined here - http://ubuntuforums.org/showthread.php?t=1971357

The ‘add-apt-repository’ is part of either one of these packages.

sudo apt-get install python-software-properties
sudo apt-get install software-properties-common

So, it is as simple as this! I like it.

---

For Debian
Ref: http://stackoverflow.com/questions/15543603/installing-java-7-oracle-in-debian-via-apt-get

echo "deb http://ppa.launchpad.net/webupd8team/java/ubuntu precise main" | tee -a /etc/apt/sources.list
echo "deb-src http://ppa.launchpad.net/webupd8team/java/ubuntu precise main" | tee -a /etc/apt/sources.list
apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys EEA14886
apt-get update
apt-get install oracle-java7-installer

Monday, November 10, 2014

(Windows 7's GNS3 Version 1.1) Step-by-Step JUNOS Olive12.1R1.9.vmdk using QEMU

1. GNS3 Version 1.1’s Preferences

2. QEMU VMs, click “New”

3. Pick the name and just use Default for Type

4. Change RAM to 1024MB (~~I didn’t try other amount of RAM~~ I also tried it with 256MB, it seems to boot just fine) [Note: Running it on QEMU seems to boot slower than running it on VirtualBox.]