Datasheet

Part I ✦ PHP: The Basics

Genuinely open source software like PHP cannot seek to limit the purposes for which it is

used, the people allowed to use it, or a host of other factors. The most critical of these rights

is the one allowing users to make and distribute any modifications along with the original

software. In the most extreme case, where one or more developers decide to release a sepa-

rate, complete version of a piece of software, this practice is referred to as code forking.

If somewhere down the road you develop irreconcilable differences with the PHP develop-

ment team, you can take every bit of code they’ve labored over for all these years and use it

as the basis of your own product. You couldn’t call it PHP, and you’d have to include stuff in

your documentation that gave due credit to the authors— the rationale is that source code

distributions make it next to impossible for any single person or group to hijack a program to

the detriment of the community as a whole, because every user always has the power to take

the source and walk.

Users new to the open source model should be aware that this right is also enjoyed by the

developers. At any time, Rasmus, Zend, and company can choose to defect from the commu-

nity and put all their future efforts into a commercial or competing product based on PHP. Of

course, the codebase up to this point would still be available to anyone who wanted to pick

up the baton, and for a product as large as PHP that could be a considerable number of vol-

unteer developers.

This leads to one other oft-forgotten advantage of open source software: You can be pretty

sure the software will be around in a few years, no matter what. In these days of products

with the life spans of morning glories, it’s hard to pick a tool with staying power. Fans of OS/2,

Amiga, NeXT, Newton, Firefly, Netscape, BeOS, Napster, and a host of other once-hot technolo-

gies know the pain of abandonment when a company goes belly-up, decides to stop support-

ing a technology, or is sold to a buyer with a new agenda. The open source model reduces the

chances of an ugly emergency port in a couple of years and thus makes long-term planning

more realistic.

Many extensions

PHP makes it easy to communicate with other programs and protocols. The PHP develop-

ment team seems committed to providing maximum flexibility to the largest number of users.

Database connectivity is especially strong, with native-driver support for about 15 of the most

popular databases plus ODBC. In addition, PHP supports a large number of major protocols

such as POP3, IMAP, and LDAP. PHP4 added support for Java and distributed object architec-

tures (COM and CORBA), making n-tier development a possibility for the first time. PHP5

extends this support even further, offering a fully incorporated GD graphics library and

revamped XML support with DOM and simpleXML.

Most things that PHP does not support are ultimately attributable to closed-source shops on

the other end. For instance, Microsoft has not thus far been eager to cooperate with open

source projects like PHP. Potential users who complain about lack of native Mac OS 9 or .NET

support on the PHP mailing list are simply misinformed about where the fault lies.

Fast feature development

Users of proprietary Web development technologies can sometimes be frustrated by the

glacial speed at which new features are added to the official product standard to support

emerging technologies. With PHP, this is not a problem. All it takes is one developer, a C

compiler, and a dream to add important new functionality. This is not to say that the PHP

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