sábado, 18 de fevereiro de 2017

How to save your Battery

How to save your battery.

Charging overnight won't degrade really. But charging while using the phone surely will.

Every rechargeable battery has certain number of charge discharge cycles which is specific to its capacity (current output or voltage).

The Basis for charge discharge cycles is the Reversible reaction occurring in the battery.
  • (Li+ + e- → ← Li-) ( → Charge ; ← Discharge)
Excessive charging will not help, in the other way it corrodes the electrode enhances the degradation rate of the electrolyte.

So, here's my suggestion - Use your phone from 100% to 5% and only then leave it for charging.

Don't take it to 40% and put it on charge and still keep using it. Battery temperatures can reach around 40°C while you're using your phone with the charger plugged in and that's not good for you battery life.

There are two main types: Lithium ion and Lithium polymer, both are having different chemistries and they are not same. Lithium polymer is light weight and can have more Coulombs* ratings, which means capable of giving more current than lithium ion. Lithium polymer is less likely to die quickly than lithium ion by over charging. But still both lithium ion and lithium polymer can be over charged by leaving charger on.
  • 1C = 1A ⋅ 1s
  • * The coulomb (unit symbol: C) is the International System of Units (SI) unit of electric charge. It is the charge (symbol: Q or q) transported by a constant current of one ampere (A) in one second (s):
Also turn brightness down, remove from your device unneeded apps and emails, check which apps consume most battery or are get alerts, and in areas of bad reception do a network reset. A lot of battery life especially on iPhones are due to bad upgrade and apps in the background using your resources.


Therefore:
  1. Don't use your phone while charging.
  2. Leaving it to charge all night is fine, given that you're following the rule above.
  3. Charge phone only when it is under 5% capacity
  4. Check what is running on your device.

quarta-feira, 15 de fevereiro de 2017

Ubuntu 14.04.5 with Epson L455

So this is log about my experience with Epson L455 multifunction printer that I bought in Brazil.

Does it work?

Short answer: YES!

Not only I did setup the printer using only a Linux station with a Mozilla/Firefox browser, but I believe the information on the WEB and also on the "quick start sheet" that comes with the printer (in the box) it not clear about this.  You do not need to use CD/DVD or the other paid OS.

Does EPSON support Linux ?

For my surprise and exactly what made me choose the EPSON printer was that it is really committed to support GNU/Linux users.

Check this (and choose Linux OS):

Does EPSON have good documentation to support Linux, see this:

And I notice support for not only Ubuntu 14.04 and 16.04 but for other flavors of Linux as well.

Does EPSON L455 scanner and printer work over wifi without the need of a USB network host computer ?

YES!  But you need to install all the packages as describe in the documentation you downloaded, and also configure properly the network, printer CUPS and SANE conf file (all detailed in the documentation).

In less then 30 minutes I figured out (ie. followed the instructions) and was not only printing with quality control but also: scanning documents and changing the network DHCP IP to a fixed IP address using just the a web browser connected to the printer WEB-GUI.  And also, don't forget to change the Admin password!

Does it work with Android, to print and scan direct to and from your phone ?

YES!  But you need to download and configure from Google Play the EPSON iPrint app.  Should work with iPhone too.


Final words:  

EPSON, THANK YOU!!!!!!  

GNU/Linux community loves you!


sexta-feira, 23 de setembro de 2016

Ignorância Sobre a Própria Burrice

"A burrice no Brasil tem um passado glorioso e um futuro promissor." - citando: Roberto Campos

Com mais de uma década de pesquisa, David Dunning, um psicólogo da Universidade de Cornell, demonstrou que os seres humanos acham “intrinsecamente difícil ter uma noção do que não sabem”.

Se um indivíduo não tem competência em raciocínio lógico, inteligência emocional, humor ou mesmo habilidades de xadrez, a pessoa ainda tende a classificar suas habilidades naquela área como sendo acima da média.

Várias pesquisas psicológicas estão chegando à conclusão que a incompetência priva as pessoas da capacidade de reconhecer sua própria incompetência. Ou seja: as pessoas burras são burras demais para saber que são burras.

E essa desconexão pode ser responsável por muitos dos problemas da sociedade.

REF:  https://hypescience.com/ignorancia-sobre-a-propria-burrice-pode-explicar-muitos-dos-problemas-da-sociedade/

quinta-feira, 25 de agosto de 2016

How to prepare WD My Passport Ultra 1TB for Linux backup

I bought a WD My Passport Ultra 1TB for Windows because I was only able to find it or the MacOS version in the stores, because it had good reviews and good price < US$60

The cons is that it is not good for Linux backup out-of-the-box because NTFS does not preserve ExtFS ownership (user/group).

The second bad news is that gparted will not be able to resize the installed partition not even if you try to use Windows in virtualbox.  Actually with virtualbox it will not be able to mount the formated partition.

So you will need to use a system with Win 7 so you can use a Windows partitioning program (eg. Partition Programs) and than resize the factory installed NTFS "data" partition.

The new size should be, say, 24~340GB ( leave this space so you can exchange data with Windows (your friends or family) and to keep the special features of WD that are native stuff to Windows and avoid it from causing problems (or void your warranty).

You should now create the new Ext4 file system with the empty space, but also reformat the NTFS partition, because the native version is not correctly detected or mounted with ntfs-3g.

I choose the names for the partitions below to be easily identified.

At the end of the process you should have something like this:

1) WD_NTFS with about  32 GB
2) WD_EXT4 with about 968 GB




3) Also, does not show, but there is a hidden partition (like a CD-ROM) that WD stores the special crypto stuff and firmware copy (this is what my research found).

Considerations:

The lack of capability of gparted to handle this type of filesystem is really frustrating.  How can this be true with so many talented people in our GNU community ?

Also, I understand now that WD really ignores Linux users. This is a sad situation since most users I know and worked with, for several years, are all Linux users and we usually choose WD HDD, at home and at work.  But, from now on, I will start to choose new brands that support linux users (WD do you hear me now?!).  And you should too.

I bought a Seagate 2T similar size at < $70 and was able to use gparted to resize and create Ext4fs with no hassle.  Seagate "hear us Linux users" better.

Proud Linux User.

segunda-feira, 2 de novembro de 2015

FERRAMENTAS LINUX: Aptik Backup dos seus temas, PPA e pacotes

Ao reformatar uma máquina com o Ubuntu para instalar outra versão do zero, um dos seus maior desafios é o de ter que reinstalar todas as aplicações, utilitários e ferramentas novamente.  Existem vários programas e scripts que se propõem a fazer isso, veja o opção do APTIK Backup no link:
FERRAMENTAS LINUX: Aptik Backup dos seus temas, PPA e pacotes


quinta-feira, 16 de julho de 2015

How to update Oracle Java on Ubuntu - faster then PPA releases

It usually takes a few days for a PPA repository to update Oracle JAVA releases.

You can solve this (for Debian based Linux distros) by making packages using "java-package" a few times (for various architectures), then distributing them internally.

If you don't have it installed open a console and type:

sudo apt-get install java-package

The big plus side is that this method always works; no matter how crazy Oracle's web pages become. Oracle can no longer break my build or stop my work, specially when Internet-banking depends on it!

The downside is that it's a bit more work to set up initially.

STEP-BY-STEP (ie. as the old music goes...)

1. Download the tar.gz files manually using your browser (ie. thus "accepting" their terms)

http://www.oracle.com/technetwork/java/javase/downloads/index.html

2. Run at prompt command:
         make-jpkg <java-package-name-xxx.tar.gz>.
   this will create a file named: "oracle-javaX-jXX_X_XXX.deb"
   Note that you may get some messages during the make-jpkg, just ignore them.

3. Distribute it within your organization (or your family devices)

For distribution over the Internet, I suggest using a password protected apt repository or provide raw packages using symmetric encryption:

passphrase="Hard to crack string. Use /dev/urandom for inspiration."
gpg --batch --symmetric --force-mdc --passphrase-fd 0 \
   oracle-javaX-jXX_X_XXX.deb <<< "$passphrase"

Of course providing (unencrypted) .deb packages on the internet is probably a violation of your license agreement with Oracle, which states:

    ... Oracle grants you a ... license ... to reproduce and use internally the Software complete and unmodified for the sole purpose of running Programs"

On the receiving end, if you have a password protected apt repo, all you need to do is apt-get install it. If you have raw packages, download, decrypt and dpkg -i them.

Works like a charm!

REF: http://stackoverflow.com/users/337079/mogsie

sábado, 11 de julho de 2015

How to Increase RAM available to Raspberry Pi CPU or GPU


Raspberry Pi 2 has 1,024MB RAM that is partitioned between the CPU and the GPU. If the Pi is working as a headless server or the Pi desktop is being accessed via VNC (which doesn't utilize the GPU) the memory split between the two processors can be altered to assign more memory to the CPU for running applications.
  • Default GPU memory on Raspbian is set to 64MB and the minimum recommended to ensure proper operation is 16MB.
  • Pi Camera Module requires a minimum of 128MB RAM.
  • Kodi Media center requires a minimum of 256MB RAM for the GPU, to avoid choppy video playback.
To modify GPU memory to 256MB either:
  1. edit /boot/config.txt and set gpu_mem=256;
    or
  2. run sudo raspi-config and select option 8 Advanced Options -> A3 Memory Split and modify value to 256
Save the change, reboot the Pi, and enjoy the CPU memory boost!