Although it sounds simple, but please trust me that it always troubled me.
OS level Cron is a good choice but it does not have any protection against multiple execution. Let’s imagine you have created an event that executes every 10 seconds, but the logic inside the event (i.e. curl) can take longer than 10 seconds, so it can pile-up. In the worst case, when an event contains a follow up action of ‘insert’ query, it can cause duplication.
Database layer of scheduler is useful if you just wanto modify the data without other ‘external’ action such sending email or calling another php script. It is also useful for database hosted on AWS RDS cloud.
Gearman provides a generic application framework to farm out work to other machines or processes that are better suited to do the work. It allows you to do work in parallel, to load balance processing, and to call functions between languages. It can be used in a variety of applications, from high-availability web sites to the transport of database replication events.
Imagine you crawling multiple website base on today captured records. Gearman help you distribute task evenly across available client, changing a ‘serial’ process into ‘parallel’. The speed it give you help to avoid the above mentioned deadlock situation. However, it still not protect against multiple execution.
FTDI has been acting very unprofessional by pushed out a new driver with Windows Update that bricks counterfeit/clone/incompatible FTDI chips by setting the Product ID to “0000”.
Here is the process that worked for me to return the FTDI chip back to its original VID:PID of 0403:6001 from a Linux (Ubuntu) computer.
Plug in your bricked device. If you run “lsusb” it should show a device at “0403:0000”.
I am using Ubuntu 14.04
To run Processing, you need to have JAVA. By default, ubuntu do not come with JAVA pre-installed due to licensing issue (DAMN! These biz ppl is blocking the earth turning again).
There are 2 type of java runtime you can install, one from openJDK and another one from Oracle. Processing2 at this time of writing only work with the later one. Follow this tutorial on how to install Oracle Java to your ubuntu machine. The process can take up to 3 hours if you have a slow Internet line.
After successfully installed, you may proceed to download processing. I like to place my processing under /opt.