Thinkpad T4210?

What do you call a Thinkpad laptop which has a T420 motherboard but T410 casing? Is it a T420 or T410? Or we should call it a hybrid of both, a T4210? More on this later.

I spend most of my computing time switching between Google Chrome and Bash shell, especially the later.  Therefore, a laptop with the best keyboard is essential to keep my hands and fingers happy, especially if you're suffering from Repeative strain injury (RSI). But this is manageable after all these years as I learned to how reduce the muscle spasm through massaging the correct trigger points.

If you ask me what is my dream laptop, it should be the legendary Thinkpad, especially the T-series or the lightweight X-series. Why so? If you spend a lot of time in the console which requires a lot of typing, a laptop with the best keyboard is a must, if you want to reduce injury to yourself. If you can, go for the classic keyboards (7 rows) instead of the newly introduced Precision keyboards (6 rows). After using both keyboards for a long period of time, I firmly believed that Lenovo made a big mistake by moving to Precision keyboards.

I used to own a E-series Thinkpad, which unfortunately, a cheaper, misleading, and fake version of Thinkpad without the durability and maintainability. Forget also the R-series, which is another economic version that is riding on the Thinkpad fame.

After reading the Used ThinkPad Buyers Guide, I bought or started to collect a used ThinkPad T420 Everything seemed good enough and looks like grade-A quality. Hardware details by inxi as shown:
$ inxi -b
System:    Host: motoko Kernel: 3.19.0-25-generic x86_64 (64 bit) Desktop: Gnome 3.16.3
           Distro: Ubuntu 15.04 vivid
Machine:   System: LENOVO product: 4180CTO v: ThinkPad T420
           Mobo: LENOVO model: 4180CTO Bios: LENOVO v: 83ET63WW (1.33 ) date: 07/29/2011
CPU:       Dual core Intel Core i5-2540M (-HT-MCP-) speed/max: 842/3300 MHz
Graphics:  Card: Intel 2nd Generation Core Processor Family Integrated Graphics Controller
           Display Server: X.Org 1.17.1 drivers: intel (unloaded: fbdev,vesa) Resolution: 1600x900@60.0hz
           GLX Renderer: Mesa DRI Intel Sandybridge Mobile GLX Version: 3.0 Mesa 10.5.2
Network:   Card-1: Intel 82579LM Gigabit Network Connection driver: e1000e
           Card-2: Intel Centrino Advanced-N 6205 [Taylor Peak] driver: iwlwifi
Drives:    HDD Total Size: 500.1GB (14.8% used)
Info:      Processes: 253 Uptime: 1:16 Memory: 2738.2/7760.8MB Client: Shell (bash) inxi: 2.2.16 

Although the stated maximum memory of the machine is 8GB, the result returned by dmidecode command shows otherwise, maximum supported memory is 16GB.
$ sudo dmidecode -t 16
# dmidecode 2.12
SMBIOS 2.6 present.

Handle 0x0005, DMI type 16, 15 bytes
Physical Memory Array
        Location: System Board Or Motherboard
        Use: System Memory
        Error Correction Type: None
        Maximum Capacity: 16 GB
        Error Information Handle: Not Provided
        Number Of Devices: 2

Unfortunately, after googling the full hardware details of the machine. I've noticed that the integrated Web Cam and fingerprint reader are missing from the laptop. It seems the seller rebuild the the laptop using a T410 case and T420 motherboard. I maybe wrong on this but that the best conclusion I can reach so far. Honestly, I have no one else to blame but myself but nevertheless, I can survive without these two features. Note to self, don't travel when buying any items.

On a related note, David Hill of Lenovo was conducting surveys on exploring on the idea of reintroduce a "Retro Thinkpad". Interesting outcome on the result of the surveys.

EPEL Yum Repository in CentOS

As Ansible, an automation tool, is not included to the default Yum repository in CentOS 6, you've to setup Extra Packages for Enterprise Linux (EPEL) Yum repository. I found this article on setting up EPEL repository and realize that I've been doing it the wrong way all this while. Instead of downloading the EPEL rpm package separately, we can install it directly as it's already located within the CentOS Extra Repository just by running the command below.
$ sudo yum install epel-release

Extra information on the epel-release package.
$ yum show epel-release
......
Installed Packages
Name        : epel-release
Arch        : noarch
Version     : 6
Release     : 8
Size        : 22 k
Repo        : installed
From repo   : extras
Summary     : Extra Packages for Enterprise Linux repository configuration
URL         : http://dl.fedoraproject.org/pub/epel/
License     : GPLv2
Description : This package contains the Extra Packages for Enterprise Linux (EPEL) repository
: GPG key as well as configuration for yum and up2date.

Listing the files within the epel-release package.
$ rpm -ql epel-release
/etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
/etc/rpm/macros.ghc-srpm
/etc/yum.repos.d/epel-testing.repo
/etc/yum.repos.d/epel.repo
/usr/share/doc/epel-release-6
/usr/share/doc/epel-release-6/GPL

Getting the list of RPM packages from EPEL repository.
$ yum list | grep epel

Since this is third-party YUM repository, certain system administrator may prefer to disable it by default and only install certain package from it when necessary.
$ cat /etc/yum.repos.d/epel* | grep enabled
enabled=0
enabled=0
enabled=0
enabled=1
enabled=0
enabled=0
$ sed -i 's/enabled=1/enabled=0/g' /etc/yum.repos.d/epel*
$ cat /etc/yum.repos.d/epel* | grep enabled
enabled=0
enabled=0
enabled=0
enabled=0
enabled=0
enabled=0

If you've installed any packages from this Yum repository. You should clear all the downloaded cache RPM packages..
$ yum clean all

Unfortunately, to perform any yum commands against this repository, we've to explicitly state the repository for every command. Some examples.
$ yum search --enablerepo=epel ansible
$ yum list --enablerepo=epel | grep epel | grep ansible
$ yum install --enablerepo=epel ansible

Indeed a bit hassle to type all these commands. You can create an alias to reduce the needless typing.
$ alias yumepel="yum --enablerepo='epel'"
$ yumepel search ansible