Posts Tagged ‘diagram’

The Best Most Effective Search Engine Optimization SEO tips or how to stay ahead of your competitors

Friday, October 27th, 2017


The 16 most effective search engine optimization tips

I've found an infogram that is showing the best practices of Search Engine Optimization as today SEO has been dependent strongly on this factors I suggest you closely check your site, whether all of the 16 pinpointed tips are already implemented in your site if not you better implement them before the robots (Machine Learning), Cloud Computing and the rest of the modern tech savy mambo jambo stuff modern technology takes over SEO ranking in Google. If you run a start up business like me this tips will definitely help you to keep up in the list of Google, Bing and Yahoo ahead of your competitors.

Enjoy Learning and please share anything you find missing on the diagram which you already do to Boost Up your SEO!

Howto install XCache Debian on GNU / Linux to accelerate Apache Webserver – XCache Best alternative to outdated PHP cacher EAccelerator

Thursday, February 26th, 2015

I was using Eaccelerator until recently on all Apache / PHP / MySQL  (LAMP) web-servers as a caching engine (Webserver accelerator) across all Debian GNU / Linux Lenny / Squeeze / Etch servers.
However recently, I've noticed in phpinfo output on some of the Debian hosts, that eaccelerator was loaded but showed:

 Caching Enabled false



Our servers are quite busy serving about 50 000 to 100 000 requests and thus not having enabled caching puts a lot of extra load on the CPU and eats a lot of memory which were usually saved by eAccelerator.
Logically I tried fixing the issues following some Stackoverflow threads recommendations such as this one but didn't work I tried playing manually spending hours trying to make eaccelerator run again and as a final mean, I even tried to upgrade eaccelerator to newer version but noticed the latest available eaccelerator version 0.9.6 was 2.5 years old (from 03.09.2012). Thus while there is no new release, just make s so just to make sure I didn't break the module with (default Debian bundled distribution package which is also installed on the servers)  re-installed eAccelerator from source 

This didn't worked either and since I was totally pissed off by the worsened systems performance (CPU load increased with to 10-30%) per server, I looked for some alternatives I can use and in the mean time I learned a bit more about history of PHP Accelerators, I learned some interesting things such as that  ionCube (PHPA) was the  first PHP Accelerator Apache like module (encoding PHP code),  created in 2001, later it become inspirational for  birth to PHP-APC (Alternative PHP Cache) Apache module. 
There is also Zend Opcache PHP accelerator (available since PHP 5.5 onwards)  but since Zend OpCache caches well PHP Zend written PHP code and servers run PHP 5.4 + sites are not using Zend PHP Framewosk  this was an option.
Further investigation lead me to MMCache which is already too obsolete (latest release is from 2013), PHPExpress – PHP Encoder which  was said to run on Windows, Linux, FreeBSD, NetBSD, Mac OS X, and Solaris) but already looks dead as there were no new releases since January 2012) and finally Lighttpd's XCache.

To give you an idea on what exactly is the difference between Apache Webserver with PHP-APC Caching or other PHP Cacher enabled and the Standard way PHP Interprets PHP scripts below is a diagram:


Obviously my short research shows that from all the available PHP Cache Encoder / Accelerators only ones that seemed to be recently updated (under active development) are APC and XCache.
I've already used PHP-APC earlier on some servers and was having having some random Apache Webservers crashes and weird empty pages with some PHP pages and besides that APC is known to give lower speed in PHP caching than Eaccelerator and XCache, leaving me with the only and logical choise to use XCACHE.

Here is how Xcache developers describe their opcacher:

XCache is a free, open source operation code cacher, it is designed to enhance the performance of PHP scripts execution on servers. It optimizes the performance by eliminating the compilation time of PHP code by caching the compiled version of code into the memory and this way the compiled version loads the PHP script directly from the memory. This will surety accelerate the page generation time by up to 5 times faster and also optimizes and increases many other aspects of php scripts and reduce website/server load.


Thanksfully XCache is shipped by default with all Debians (Etch /Lenny / Squeeze / Wheezy)  Linuces so to install it just run the standard apt cmd:

apt-get install –yes php5-xcache

Then to enable XCache all I had to do is edit /etc/php5/apache2/php.ini and place below code

debian-server:~# vim /etc/php5/apache2/php.ini


;; install as zend extension (recommended), normally "$extension_dir/"
;;zend_extension = /usr/lib/php5/20100525/


xcache.admin.enable_auth = On
; Configure this to use admin pages
; xcache.admin.user = "mOo"
; xcache.admin.pass = md5($your_password)
; xcache.admin.pass = ""

; ini only settings, all the values here is default unless explained

; select low level shm/allocator scheme implemenation
xcache.shm_scheme =        "mmap"
; to disable: xcache.size=0
; to enable : xcache.size=64M etc (any size > 0) and your system mmap allows
xcache.size  =                16M
; set to cpu count (cat /proc/cpuinfo |grep -c processor)
xcache.count =                 1
; just a hash hints, you can always store count(items) > slots
xcache.slots =                8K
; ttl of the cache item, 0=forever
xcache.ttl   =                 0
; interval of gc scanning expired items, 0=no scan, other values is in seconds
xcache.gc_interval =           0
; same as aboves but for variable cache

Note that Debian location which instructs xcache to load in Apache as a module is xcache.ini – e.g. /usr/share/php5/xcache/xcache.ini, so instead of placing above configuration right into php.ini you might prefer to place it in xcache.ini (though I personally prefer php.ini) because it is easier for me to later control how PHP behaves from single location.

To test whether XCache is enabled for Apache Webserver:

Create phpinfo.php somewhere in DocumentRoot (in my case this was /var/www/php_info.php)

debian-server:~# vim /var/www/php_info.php



When you access the php_info.php in browser you will get XCache loaded as in below screenshot:



To Test whether Xcache is enabled also for PHP CLI (applications set to run as a crontab – cronjob) :

debian-server:~# php -v
PHP 5.4.37-1~dotdeb.0 (cli) (built: Feb  2 2015 05:03:00)
Copyright (c) 1997-2014 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2014 Zend Technologies
    with XCache v3.2.0, Copyright (c) 2005-2014, by mOo
    with XCache Cacher v3.2.0, Copyright (c) 2005-2014, by mOo


Once it is tested as successful install you might want to enable the XCache admin (which is disabled by default), to enable XCache Admin on Debian you need to generate new password for it first like so:


echo -n "xcache_rulez" | md5sum


Then you need to add in /etc/php5/mods-available/xcache.ini

debian-server:~# vim /etc/php5/mods-available/xcache.ini
xcache.admin.enable_auth = On
; Configure this to use admin pages
 xcache.admin.user = "admin"
; xcache.admin.pass = md5($your_password)
 xcache.admin.pass = "change_with_above_generated_password_here"


To enable admin and be able to access it in a browser (if you're using as a documentroot /var/www/ and docroot supports interpretting php scripts and (has AllowOverride All) enabled to also support htaccess authentication do:

debian-server:~# cd /var/www/
debian-server:~# ln -sf /usr/share/xcache/htdocs/ xcache

When you access you should see in browser some statistics along with all configured xcache options:


If you have time you can play with the options and get some speed minor speed improvements. The overall increase in page opening XCache should give you is between 100% – 190% !

Enjoy 🙂

Ditaa convert ASCII diagrams into bitmap graphic (pictures)

Monday, May 12th, 2014

As part of my passion for ASCII art, I've found another interesting tool useful to ASCII art maniacs like me, the tool is called ditta and is able to convert manually drawn ASCII art diagrams to graphics, below is tool description from my debian apt-cache as well as a screenshot:

 apt-cache show ditaa|grep -i ditaa -A 4

Package: ditaa
Priority: optional
Section: graphics
Installed-Size: 164
Maintainer: David Paleino <>

Filename: pool/main/d/ditaa/ditaa_0.9+ds1-2_all.deb
Size: 107270
MD5sum: 05ec52d9274b954b053f1835ca5d7a7f
SHA1: 792d91d05fff2a2a19c0ebce317351d138436c18
SHA256: c4319d32e7918aab782e2f38cdad745bc9023f9f09a999033d983095ee4f70d5

 DiTAA is a small command-line utility that can convert diagrams drawn using
 ASCII art ("drawings" that contain characters that resemble lines, like | /
 and -), into proper bitmap graphics.
 DiTAA also uses special markup syntax to increase the possibilities of shapes
 and symbols that can be rendered.


To install ditaa on Debian and Ubuntu Linux:

debian:~# apt-get install --yes ditaa

Ditaa text diagram to Graphics converter is also available in Fedora Linux and in Source RPMs to be used on Redhat Based RPM distributions.
To install in most of RPM based Linuxes:

[root@fedora:~]# yum install -y ditaa

For most people probably Ditta will not be of any value except as a PoC and of a Hack value just like Ditaa's home page suggests. Nomatter that Ditta is cool but has just 2 drawback it doesn't understand non-latin characters i.e. Cyrillic and requires Java Virtual Machine .. but if you're a real geek you will do  the sacrifice to install a whole bunch of the heavy java for the sake of some oldschool fun 🙂 Being written in Java makes Ditta multi-platform, but you will need a Java VM version of at least 1.6 (it doesn't work with Java 1.5).

The format Ditta understands is close to HTML

<ditaa [optional parameters]>
... (some ditaa-code) ...

There are also special tags understood by Ditta which are automatically turned into shaped graphical buttons and forms.

Possible tags

Not all shape selector tags are documented on the ditaa site. A quick source scan revealed:

tag Description
{c} decision(Choice)
{d} document
{io} input/output, parallelogram
{mo} manual operation
{o} ellipse, circle
{s} storage
{tr} trapezoid (looks like an inverted {mo} )

Here is an example Ditta code

<ditaa round noedgesep right>
    +--------+   +-------+    +-------+
    |        | --+ ditaa +--> |       |
    |  Text  |   +-------+    |diagram|
    |Document|   |!magic!|    |       |
    |     {d}|   |  c478 |    |       |
    +---+----+   +-------+    +-------+
        :                         ^
        |       Lots of work      :

This Ditta code will generate following picture:


To learn more on ditta please check Ditaa's Project homepage on Sourceforge
Many thanks to Cybercity's 30 Cool Open Source Software of 2013 for inspiring this post.