Buy Cialis Online

As we started the project of the electronic auction PoloMercantil.com, we knew that the proprietary software costs would be too high for our financial resources. Our only option then was to make use of Open Source Code softwares.

However, within the Open Source Code there are lots of softwares to choose from, and it?s up to the system analyst/programmer to pick the ones that best suit the project goals.

In our case, we picked Linux as our operating system. However we faced a big question: Which Linux distribution ? There are dozens of linux distributions, each one with specific advantages, sometimes with or without paid services.

We chose linux Slackware because we thought that it would suit better our needs, in terms of stability and reliability. Slackware is a conservative distribution, meaning that it only offers in its distribution package kernel versions and third party libraries, once it?s been proved to be stable and reliable. As a result, Slackware is one the most stable Linux operating system on the market. If the user wishes the most recent Linux kernel and libraries, we recommend to look for a different distribution.

Another reason for us picking Slackware, was because of its text interface, which at the beginning may become a bit difficult, in the long run however it offers a better understanding of the Linux environment. This way most of Slackware configurations are done thru text scripts.

Once it was set the operating system, we picked Apache as our web server. Apache is one of the most popular web server in the internet. For server programming language, we chose PHP. Also, a very popular programming language. Our experience with Apache/PHP proves that this setup is very reliable, working extremely well in our production environment. For workstation programming language, we chose javascript, which besides of having a simple syntax, it offers lots of resources.

Apache web server is really a complete web server. Also, it can become very complex with many configuration setups.

For our database, we picked Postgresql. This database has been made available to the public for more than 15 years, and besides of being well debugged, it offers so many resources that it has become one of the best database options from Open Source Code softwares. Extremely reliable, Postgresql has reported cases where there have been databases in production with over 4 terabytes. Besides all of that, Postresql is not the most popular Open Source Code database. A matter of marketing ? Probably.

As for the programming language PHP, we had to use an object oriented application structure. There are many PHP application structures being offered with Open Source Code license. Object oriented application is very important, because it makes programming very easy and scalable up to the point where the system may grow without many problems. Also, it helps to keep PHP code separated from HTML, with the help of some specific libraries, such as Smarty. We make use of Smarty library and we believe that it is a very important resource, which can even make web pages faster thru the use of its cache functions.

Also a very important set of libraries worth mentioning for PHP systems, is the PEAR libraries. In PEAR web site, among the many libraries being offered, there are the database interface DB and the MAIL_QUEUE, which sends emails thru the use of database.

As we came to the end of the project PoloMercantil, we had to use some sort of real time database replication. For that we chose the DRBD and Heartbeat libraries. The use of database replication is very important and should not be postponed. Just after 3 months our system got into production, our server hard disk became bad. Thru the use of DRBD/Heartbeat we were able to put the system back into production within seconds, without loosing any data. DRBD/Heartbeat replication is done thru the use of a lan network between the server and slave nodes.

Our project also makes use of ImageMagick (enlarge and reduce images), Iptables (firewall), Tsearch2(text search in portgresql) and Mon (linux monitoring tasks).

Also a very important library worth mentioning is the pseudo APC compiler for PHP. Speed is always a critical factor for internet sites.

PoloMercantil is already in production and based upon our experience we can say that the Open Source Code softwares we picked, proved to be extremely reliable and stable. Open Source Code softwares can certainly be an excellent option for developing web sites.

Roberto Sedycias

IT Consultant for PoloMercantil

This article is under GNU FDL license and can be distributed without any previous authorization from the author. However the author?s name and all the URL?s (links) mentioned in the article & biography must be kept.

Start Promoting A Great New Product In A Open Market. I Can Send You French Words/marketing If You Need Me To. Regardez La Télévision En Direct Sur Votre PC Tout De Suite! Make 75% A Sale!

Tv Sur Votre PC – Computer TV/French – Great/Cheap PPC.

In November of this year Sun Microsystems moved to “open source” status for Java, after a decade of maintaining proprietary status for the portable programming language. Specifically, Sun has placed Java into the public domain by putting it under GPL – an acronym for General Public License. What this means is that software programmers will have vastly increased freedom to develop programs based on Java and to develop modifications for the language itself.

It also puts Sun into the mainstream with other major platform developers such as Linux. While the company had put its Solaris operating system into open source status some time ago, Java is a highly distributed consumer platform and providing open source access to it gives the company a real boost in its standing among its peers. Perhaps more important, it will stimulate further development of consumer oriented Java-based programs. It is estimated that eight out of every ten cell phones have a Java application running on them.

A GPL use requires that any product developed under such licensure be returned to the “open source community” and remain, in effect accessible to all. Sun’s variation on this principle has an exception for applications built on the Java “Virtual Machine,” a platform that the company made available to software developers some time ago.

What this exception does is allow continued development of proprietary software written for Java, which keeps the language viable as a platform for revenue producing products. Prior to the switch to GPL status, Java program developers had to pay a licensing fee to Sun.

IBM has been after Sun to take Java to open source status for years. Their Works Projects has been a center for the development of open source products, primarily based on Linux. From their perspective, Sun’s decision to grant GPL status for Java is viewed as an opportunity to unite with Linux and provide a stronger platform to challenge Microsoft. The politics of software can be enormously complicated, especially when there’s an elephant like Microsoft in the house. But what Sun has accomplished with this move is provide an opportunity for programmers to zero in on Java products as potentially large revenue sources.

Unlike Linux, which was spun off of UNIX to provide an alternative to Windows, Java stands in a class of its own. While Linux has survived in the marketplace, it has never mounted a major challenge to Windows. Java’s unique qualities and the intellectual property that protects those qualities will now be an open book for programmers developing new applications.

It will also provide the opportunity to bundle Java products with Linux based software. Sun’s internal interest in this move is to stimulate more developers to use the language, in order to revive its own internal software business. Since taking a huge hit in their high-end server market, Sun has been struggling to find a new path and has increasingly looked to software as an opportunity.

Sun’s EVP for software summed up the value of the move for the company and its product. “People have been hesitant to distribute Java worldwide with Linux (distributions) because of (concerns over) license alignment,” Green said. “This is the last gate to ensure that Java will be distributed worldwide.”

Ground source heat pumps (GSHPs), often called geothermal heat pumps, tap into the heat naturally generated many meters below the surface of the earth. Just a little ways down, the earth’s temperature is warm and relatively stable, so these systems can bring controllable and effective heating, cooling, and hot water to residential and commercial buildings. Best of all, they allow people to do all this without having to use expensive and carbon-producing fossil fuels such as oil and gas.

There are two types of ground source heat pump systems: those with closed loops and those with open loops. In closed loop systems, liquid (usually with some sort of antifreezing/antiboiling agent mixed in) circulates through pipes buried beneath the earth’s surface. During the winter, when the goal is warming a house, the fluid absorbs heat from the earth and carries back to the building. This very hot liquid can be effectively used to heat a home, and also quite obviously becomes a free-flowing source of useable hot water. During the summer, the system is designed to actually draw heat out of the building, and either use it to heat water for household use or deliver it back into the ground. Open looped systems are similar, except that the water supply within the pipes is continually refreshed.

The bulk of geothermal (GSHP) systems are the pipes that are buried far underground, so what is needed in your home is a unit likely no bigger than your current hot water heater and furnace. If you currently use oil, you may be able to get rid of or at least substantially downsize the size of your oil tank. Many people worry about the longevity and upkeep costs of this type of system because the bulk of the cost goes into burying the pipe underground. Recently however many companies have been offering 40-75 year warranties on the parts of the system that is buried.

If you already have a forced air oil or gas-fed furnace system it may be easy for you to convert to what is called a “dual system”. In this case you would choose which heating and cooling system would be primary at any particular time – most likely the geothermal system – and the other system will only work when needed, such as during an extremely cold spell in the winter.

GSHPs are quiet and safe. There are no exposed parts, fans, storage tanks, etc. that can hurt kids or pets. Nothing is burned so there is no flame. The heating source is the earth so there is nothing to wear out. They are also quiet because the earth is doing the work of the motors in your current furnace.

The initial cost for ground source heat pumps is greater than that of a conventional oil or gas system. However, that initial cost is often made up in three to six years depending on the cost of fuel and the temperature in your area. The greatest benefit of these systems is that you no longer have to use oil or gas at all, so not only are you not subject to the price fluctuations and uncertainty of these fuels, but you also reduce your own “carbon footprint” in the process.

Ground source systems are easy to install, particularly when they are replacing another forced-air system. In this case it is as simple as a retrofit after the pipes are placed. However, they can also be installed to completely replace the system you already have. If you don’t already have central air conditioning, that can be an automatic and immediate benefit of these systems. Contact an experienced installer and he or she can tell you exactly what would be involved in installing a geothermal heat pump in your home.

How To Buy Your Favorite Designer Brands For A Fraction Of The Retail Price. Most Popular Brands Available: Gucci, Dior, Fendi, Prada, Armani, D&g, Cavalli, Ferragamo. Find Tons Of Discount Designer Apparel, Accessories, And Handbags. Up To 90% Off!

Designer Wholesale Sources.