LUKI NOTES

APCu is one of caching application for PHP. In this case, I use PHP 7.0 on Ubuntu 16.04. In PHP 7.0, this application is provided via PEAR. First, install PEAR. $ sudo apt-get install php-pear Install APCu. If an error occured state that there's no phpize, you need to install PHP 7.0-dev which provide phpize support. $ sudo apt-get install php7.0-dev $ sudo pecl install apcu Create APCu module configuration in PHP modules directory. $ sudo echo "extension = apcu.so" >> /etc/php/7.0/mods-available/apcu.ini Add that configuration to PHP FPM and CLI. $ sudo ln -s /etc/php/7.0/mods-available/apcu.ini /etc/php/7.0/fpm/conf.d/30-apcu.ini $ sudo ln -s /etc/php/7.0/mods-available/apcu.ini /etc/php/7.0/cli/conf.d/30-apcu.ini Restart PHP FPM.

End of Madara

ESP-01 board is different from NodeMCU DevKit (ESP-12E) board. It doesn't have USB support. You need a USB to TTL serial converter and a certain circuit to switch the board between normal boot and flashing mode. You can buy a USB to TTL converter as cheap as $1 or you can utilize your current Arduino board. First, I want to show my simple circuit using a USB to TTL converter to flash ESP-01. I use Prolific USB to TTL. It's the cheapest device you can get in the market. If you use this device on Windows operating system, you must check Device Manager and validate that the device isn't in an error state. If it's an error, you can use the solution from  HERE . The following image shows the circuit for flashing ESP-01 using a USB to TTL converter. I use an external 3.3V supply because my Prolific can provide only a 5V supply from USB and the current is too low. USB to TTL to ESP-01 If you are too lazy with push-button and resistor you can use the followin...

Besides classical music, I also like heavy metal music. X Japan is one of the most famous heavy metal bands from Japan. I like most of its music. Its tone is strong and brings me a certain feeling. One of their songs that makes me fell in love with X Japan was Kurenai. X Japan was formed in 1982. In the beginning, I don't really care about its member. Recently, when I watched 2000s concert videos, I just realized that one of its members, the guitarist, who used to appear with his blooming red hair was missing. Now I know that the guitarist, Hide, 33 years old guy, was dead in 1998 because of suicide, based on police evidence. X Japan had been disbanded in 1997 and Hide had started a solo career since then. While he still had a certain project with another music group in 1998, he was found dead in his house. His death was followed by the copycat suicides of three of his fans. In 2007, X Japan was reinvented and launched a new album. In the 2008 co...

SSH is a popular network protocol used to access remote computers through certain networks or the internet. OpenSSH is an application that provides SSH accessibility for a computer or server. A common method used to start a communication with SSH access is by providing a username and password before a secured connection is established. This method is not really safe because you provide credentials in plain text and transfer them through the network. It also makes it any scumbag individuals be easier to guess your password or perform a brute force attack in order to gain your server access. There are several possible ways that I think can be used for hardening your SSH security. Disable root access Change SSH port number Utilize RSA authentication Disable plain password login Disable root access 1) Before you disable the root access, you need to make sure that there is another user account on your remote computer. 2) Create a new user as needed. $ adduser youruser 3) Edi...

NodeMCU is popular firmware for ESP8266 WiFi SoC. When you buy a NodeMCU ESP8266 board, it must have been flashed with the firmware. But, you can also flash it anytime by yourself, for example when you want custom NodeMCU firmware. For complete documentation of NodeMCU, you can see it  here . There are a few steps to flash your board firmware. In this example, I use NodeMCU DevKit 1.0  with ESP-12E core which is easy to get in the market. If you use ESP-01, you need to see my other post about the ESP-01 flashing circuit . 1. Build the firmware. The easiest way is to build from the cloud , just follow the steps then the firmware will be sent to your email. 2. Install esptool.py. It is a python application to communicate with the ESP ROM bootloader. You can install it either from python package manager using pip install esptool or download manually from Github repository here . $ git clone https://github.com/espressif/esptool.git There are several other tools that you ca...