Install eAccelerator on Centos 5.2

Still on pursuing to make a fast httpd server, I found eAccelerator at techiecorner.com. Here is what I gathered to install the eAccelerator on my Centos 5.2.

First lookup the latest PHP eAccelerator source distribution from here.
My downloaded version is eaccelerator-

$ tar -jxvf eaccelerator-
$ cd eaccelerator-
$ phpize
$ ./configure
$ make
$ make install
after the last command, it shows this line:
Installing shared extensions: /usr/lib/php/modules/

Now we edit php.ini
$ nano /etc/php.ini
and add these line:


after saving the php.ini, I created temp folder for the eaccelerator

$ mkdir /tmp/eaccelerator
$ chmod 777 /tmp/eaccelerator

then restart the httpd:

$ httpd -k restart

to manage eAccelerator, I copied control.php
cp /usr/src/eaccelerator- /path/to/my/homepage/control.php
when I tried to browse http://comp1/control.php, it asked for password, the default is :

Username : admin
Password : eAccelerator

but then I got "This script isn't in the allowed_admin_path setting" error in some area of the page. After took a peak on my ubuntu server configuration that already running eAccelerator, I added "eaccelerator.allowed_admin_path="/path/to/my/homepage"" so my php.ini now look like this :


save the php.ini, then restart the httpd:

$ httpd -k restart

now I can login and manage the eAccelerator

Install PHP-MemCache On CentOS 5.2

I'm a linux newbie, but I want to speed up my webserver access, after googling around for days, I decided to try the php-memcache and I find most of my installation steps ini howtoforge.com. Here is what I did :

Install rpmforge repo
$ wget
$ rpm --install rpmforge-release-*.rpm

Install memcached:
$ yum install --enablerepo=rpmforge memcached
test if memcached is running:
$ memcached -m 512 -u nobody -vv

start up the memcached daemon on as many spare machines as you have. The daemon has no configuration file, just a few command line options, only 3 or 4 of which you'll likely use:
$ ./memcached -d -m 2048 -l -p 11211 -u nobody

This starts memcached up as a daemon, using 2GB of memory, and listening on IP, port 11211. The -m switch specifies the amount of memory in megabytes. The -l switch specifies the IP to listen on and finally the -p switch specifies the port to listen on. The default port is 11211 and if your machine has just 1 IP you can omit the -l parameter.

Install PHP MemCache extension
$ cd /usr/src/
$ wget http://pecl.php.net/get/memcache-2.2.3.tgz
$ tar -xvf memcache-2.2.3.tgzcd memcache-2.2.3
$ phpize && ./configure --enable-memcache && make
Copy the file memcache.so to the default module directory.
$ cp /usr/src/memcache-2.2.3/modules/memcache.so

Edit php.ini
$ nano /etc/php.ini
And add this line ini php.ini
Restart Apache2
$ /etc/init.d/httpd restart
Now the php-memcache is installed


Lewis Hamilton won German GP

HOCKENHEIM, Germany — Lewis Hamilton won the German Grand Prix on Sunday, solidifying his lead in the Formula One standings with two dramatic passes that made up for a strategic blunder by his McLaren team. Hamilton overtook Ferrari's Felipe Massa and then runner-up Nelson Piquet Jr. of Renault at the same hairpin after a crash involving Timo Glock had brought out a safety car that nearly cost the McLaren driver his fourth victory of the season. Most teams chose to pit when the safety car was out, but McLaren left its standout driver out — only to see him fall to fifth place when he pitted with 17 laps to race. But Hamilton, who leads Massa by four points in the standings, worked his way through the field before nudging past the Ferrari driver from the inside at Turn 6 and holding off Massa's outside challenge soon after. Piquet Jr., who started from 17th and earned his first career podium, couldn't hold off Hamilton when the 23-year-old Briton closed in at the same corner a few laps later.
Hamilton has eight victories in 27 races.
Briscoe prevails

LEXINGTON, Ohio — Ryan Briscoe won the Honda Indy 200, an IndyCar Series event at Mid-Ohio Sports Car course. Team owner Roger Penske made a pit-strategy call to put Briscoe out of sequence with the other contenders and it paid off with the Australian driver's second victory of the season and a 1-2 sweep for the team, as Helio Castroneves finished second. The race began about an hour after a downpour soaked the 2.25-mile, 13-turn road circuit. Officials ruled it a wet start and all the cars had to begin on grooved rain tires. But, with the track drying fast as the 26-car field took the green flag, cars began heading for pit road to change to racing slicks. Penske waited to bring Briscoe onto pit lane until Lap 6, dropping him to 16th. Penske brought Briscoe back into the pits again on Lap 23, ahead of most of the other contenders, putting him out of sequence and, eventually, working to his advantage.

"I think that was the only chance we had," Penske said. "What a great drive for Briscoe."

Valentino Rossi won the MotoGP United States Grand Prix, giving the Italian rider his first victory at Laguna Seca in Monterey, Calif.

Rossi's 66th career victory stopped defending world champion Casey Stoner's winning streak at three races. Rossi finished the 32-lap race in 44 minutes, 4.311 seconds, with a top speed of 97.72 mph.

source www.seattletimes.com


Simple backup of MySQL

Sometimes I need to quick backup my database and download it to my pc, I use mysqldump command to do that and to save time of downloading, i compress it with gzip, here the command :

$ mysqldump -u MySQLuser -pMySQLpassword --opt db-name l gzip -c -9 > /path/to/backup/folder/backup-name.sql.gz

remember not to put spaces between -p and the password

and after i've download it, I create a db-name database in MySQL, and restore the backup using command :

$ gzip -d /path/to/backup/folder/backup-name.sql.gz
$ mysql -u MySQLuser -pMySQLpassword db-name < /path/to/backup/folder/backup-name.sql

remember not to put spaces between -p and the password !!


Computer Cluster

A computer cluster is a group of linked computers, working together closely so that in many respects they form a single computer. The components of a cluster are commonly, but not always, connected to each other through fast local area networks. Clusters are usually deployed to improve performance and/or availability over that provided by a single computer, while typically being much more cost-effective than single computers of comparable speed or availability.

Cluster types:
High-availability (HA) clusters
High-availability clusters (also known as failover clusters) are implemented primarily for the purpose of improving the availability of services which the cluster provides. They operate by having redundant nodes, which are then used to provide service when system components fail. The most common size for an HA cluster is two nodes, which is the minimum requirement to provide redundancy. HA cluster implementations attempt to manage the redundancy inherent in a cluster to eliminate single points of failure.

Load-balancing clusters
Load-balancing clusters operate by distributing a workload evenly over multiple back end nodes. Typically the cluster will be configured with multiple redundant load-balancing front ends.

Grid computing
Grid computing or grid clusters are a technology closely related to cluster computing. The key differences (by definitions which distinguish the two at all) between grids and traditional clusters are that grids connect collections of computers which do not fully trust each other, or which are geographically dispersed. (The term GRID to denote a distributed computing and storage environment was coined in 1998 by Ian Foster and Carl Kesselman. It refers to the metaphor of the power grid: computing capacity from a wall outlet and no need to install and maintain complex IT infrastructures on every location that needs access to applications.) Grids are thus more like a computing utility than like a single computer. In addition, grids typically support more heterogeneous collections than are commonly supported in clusters.

Source : wikipedia


Bridges Types (3) : Arch Bridge

An arch bridge is a bridge with abutments at each end shaped as a curved arch. Arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side. A viaduct (a long bridge) may be made from a series of arches, although other more economical structures are typically used today.

Possibly the oldest existing arch bridge is the Mycenaean Arkadiko bridge in Greece from about 1300 BC. The stone corbel arch bridge is still used by the local populace. Although true arches were already known by the Etruscans and ancient Greeks, the Romans were - as with the vault and the dome - the first to fully realize the potential of arches for bridge construction.

The engineer Colin O'Connor lists 330 Roman stone bridges for traffic, 34 timber bridges and 54 aequeduct bridges, a substantial part still standing and even used to carry vehicles.

In more modern times, stone and brick arches continued to be built by many civil engineers, including Thomas Telford, Isambard Kingdom Brunel and John Rennie. A key pioneer was Jean-Rodolphe Perronet, who used much narrower piers, revised calculation methods and exceptionally low span-to-rise ratios. Different materials, such as cast iron, steel and concrete have been increasingly used in the construction of arch bridges.

Although rarely built, the Romans also introduced segmental arch bridges into bridge construction. The 330 m long Limyra bridge in southwestern Turkey features 26 segmental arches with an average span-to-rise ratio of 5.3:1, giving the bridge an unusually flat profile unsurpassed for more than a millennium. Trajan's bridge over the Danube featured open-spandrel segmental arches made of wood (standing on 40 m high concrete piers). This was to be the longest arch bridge for a thousand years both in terms of overall and individual span length.

Roman bridges featured from an early time onwards flood openings in the piers, e.g. in the Pons Fabricius in Rome (62 BC), one of the world's oldest major bridges still standing.

In China, the oldest existing bridge is the Zhaozhou Bridge of 605 AD (although bridges were built since the ancient Zhou Dynasty), which combined a very low span-to-rise ratio of 5.2:1, with the use of spandrel arches (buttressed with iron brackets). The Zhaozhou Bridge is the world's first wholly-stone open-spandrel segmental arch bridge.

Source : wikipedia

Bridges Types (2) : Beam & Cantilever

Beam bridge

Beam bridges are horizontal beams supported at each end by piers. The earliest beam bridges were simple logs that sat across streams and similar simple structures. In modern times, beam bridges are large box steel girder bridges. Weight on top of the beam pushes straight down on the piers at either end of the bridge.

A beam is a direct descendant of the log bridge, now more normally made from shallow steel 'I' beams, box girders, reinforced concrete, or post-tensioned concrete. It is frequently used in pedestrian bridges and for highway overpasses and flyovers. As is its ancestor, this bridge is in structural terms the simplest of the many bridge types.

Like most bridges that are characterized by how they are supported, beam bridges consist of one horizontal beam with 2 supports usually on either end.

Decorative beam bridges, commonly built from cedar, pine, and redwood, can span a koi pond or country creek. These free standing bridges are usually built as functional walkways or just for decoration.

Cantilever bridge

A cantilever bridge is a bridge built using cantilevers--structures that project horizontally into space, supported on only one end. For small footbridges, the cantilevers may be simple beams; however, large cantilever bridges designed to handle road or rail traffic use trusses built from structural steel, or box girders built from prestressed concrete. The steel truss cantilever bridge was a major engineering breakthrough when first put into practice, as it can span distances of over 1,500 feet (460 m), and can be more easily constructed at difficult crossings by virtue of using little or no falsework.

A simple cantilever span is formed by two cantilever arms extending from opposite sides of the obstacle to be crossed, meeting at the center. In a common variant, the suspended span, the cantilever arms do not meet in the center; instead, they support a central truss bridge which rests on the ends of the cantilever arms. The suspended span may be built off-site and lifted into place, or constructed in place using special traveling supports.

Source : wikipedia


Bridges Types (1) : Suspension Bridge

A suspension bridge is a type of bridge where the main load-bearing elements are hung from suspension cables. While modern suspension bridges with level decks date from the early 19th century, earlier types are reported from the 3rd century BC. Simple suspension bridges, for use by pedestrians and livestock, are still constructed.

Suspended well from two high locations over a river or canyon, simple suspension bridges follow a shallow downward arc and are not suited for modern roads and railroads. The suspension cables must be anchored at each end of the bridge, since any load applied to the bridge is transformed into a tension in these main cables. The main cables continue beyond the pillars to deck-level supports, and further continue to connections with anchors in the ground.

The roadway is supported by vertical suspender cables or rods, called hangers. In some circumstances the towers may sit on a bluff or canyon edge where the road may proceed directly to the main span, otherwise the bridge will usually have two smaller spans, running between either pair of pillars and the highway, which may be supported by suspender cables or may use a truss bridge to make this connection. In the latter case there will be very little arc in the outboard main cables.

Suspension bridges have the longest spans of any type of bridge. Cable-stayed bridges, the next longest design, are practical for spans up to around one kilometer.

Advantages over other bridge types
  • A suspension bridge can be made out of simple materials such as wood and common wire rope.Longer main spans are achievable than with any other type of bridge

  • Less material may be required than other bridge types, even at spans those can achieve, leading to a reduced construction cost

  • Except for installation of the initial temporary cables, little access from below is required during construction, for example allowing a waterway to remain open while the bridge is built above

  • May be better able to withstand seismic movements than heavier and more rigid bridges
Disadvantages compared with other bridge types

  • Considerable stiffness or aerodynamic profiling may be required to prevent the bridge deck vibrating under high winds

  • The relatively low deck stiffness compared to other types makes it more difficult to carry heavy rail traffic where high concentrated live loads occur

  • Some access below may be required during construction, to lift the initial cables or to lift deck units. This access can often be avoided in cable-stayed bridge construction

Source : wikipedia


Millau Bridge

Millau Bridge (formally known as le Viaduc de Millau), is the tallest vehicular bridge in the world. Designed by the structural engineer Michel Virlogeux and British architect Norman Foster, it is the tallest vehicular bridge in the world. The steel-and-concrete bridge stretches 2.6 km (1.6 miles) long and rests on 7 pillars, and the tallest one reaching 1,122ft/375m — slightly taller than the Eiffel Tower and only 38 m (125 ft) shorter than the Empire State Building. It was formally dedicated on 14 December 2004, inaugurated the day after and opened to traffic two days later.

The bridge forms the last link of the A75 autoroute, (la Méridienne) from Clermont-Ferrand to Pézenas (to be extended to Béziers by 2010). The A75, with the A10 and A71, provides a continuous high-speed route south from Paris through Clermont-Ferrand to the Languedoc region and through to Spain, considerably reducing the cost of vehicle traffic travelling along this route. Many tourists heading to southern France and Spain follow this route because it is direct and without tolls for the 340 kilometres (210 mi) between Clermont-Ferrand and Pézenas, except for the bridge itself.

Built in 3 years, it provides an alternative route from northern Europe to southern France and Spain.

Foster’s winning proposal features seven equally spaced concrete masts, the tallest of which is 245 m (804 ft) high. These split into two when they pass through the road deck, creating a needle-like eye that flexes to accommodate expansion and contraction of the deck.
The masts are profiled to appear as slim as possible when viewed from the side, reducing the bridge’s impact on its surroundings. The concrete deck is suspended on steel cables 90 m (295 ft) below the mast tops, making it the highest road bridge in the world. The deck traces a shallow curve as it crosses the valley, allowing motorists to better appreciate the scale of the bridge as they drive across.

Unusually, the client (the Department of Transport and Public Works of France) insisted that engineering firms team up with architects to enter the design competition. Foster & Partners worked on the project alongside French engineering firm Eiffage, named after Gustav Eiffel who designed the Eiffel Tower.

"The whole thing looks impossibly delicate," Foster said in a telephone interview of what he called his "sculpture in the landscape" a 394-million-euro ($523 million) project financed by construction firm Eiffage. "It is a dialogue between nature and the man-made," he said.

For nearly thirty years prior to the construction of the Millau Viaduct, the A75 autoroute had remained unfinished. Before the bridge, a crossing of the River Tarn was provided by a bridge situated in the valley bottom, in the town of Millau. Millau was then known and dreaded as a ‘great black spot’ of motoring. Kilometres of congestion and hours of waiting to transit the town recurred each year with the great surge in traffic in summer months. These slowdowns meant that the advantages of the A75 were lost. The A75 was meant to be a positive example of spatial planning, a modern, direct highway entirely free along its 340 km (210 mi) length. As it was, the traffic from the autoroute brought pollution and danger to the town of Millau.

Design and construction of the bridge took a long time. In this region, climatic conditions are tough, with violent winds. Geological characteristics of the high plateaus of Larzac are peculiar, and, because the Tarn Valley is so deep, crossing is difficult. Different approaches were investigated, and all of them were found to be very technically demanding. Ten years of research and four years of implementation were required for completion of the Millau Bridge.

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