PHP Version 4
If you've never heard of PHP, you're certainly not alone. However, you've probably visited one of the many sites driven by PHP, such as the widely popular Linux application portal Freshmeat.net.
PHP is a server-side HTML-embedded scripting language that allows developers to build web applications. PHP's features are comparable to Microsoft's ASP (Active Server Pages) and VBScript. Both PHP and ASP are interpreted scripting tools that allow HTML and code to be mixed in the same file. Both have effective APIs for building database-driven applications. However, unlike ASP, PHP is open source and cross-platform. PHP can run on Windows NT under Microsoft's IIS web server or on any UNIX variant as an Apache module or CGI.
PHP, which stands for “Personal Home Page”, was originally developed by Rasmus Lerdorf as a macro tool for tracking visitors to his home page. It grew from its simple roots into a complete tool for building web applications by version 3. Released in June 1998, PHP version 3 (often referred to as “PHP3”), was primarily developed by Andi Gutmans and Zeev Suraski.
Since then, PHP has continued to grow in popularity. It's not possible to determine exactly how many PHP-powered sites there are, but NetCraft's survey data suggest that over 500,000 web sites are running PHP. Additionally, E-Soft's Apache module survey shows over 100,000 PHP-enabled Apache servers. E-Soft anticipates PHP will become the leading add-on module for Apache, ahead of extensions for FrontPage and mod_perl.
Andi Gutmans and Zeev Suraski began working on version 4 in November 1998. Version 4 is a complete rewrite of PHP's scripting engine. Unlike PHP 3.0, the new “Zend” scripting engine bundled with PHP 4.0 is a separate product. Eventually, Zend will be used for other scripting applications. (Incidentally, the name “Zend” is derived from the the developers' names: Zeev and Andi.)
The most significant change in version 4 is a dramatic increase in speed. The Zend team posted preliminary benchmarks of PHP/Zend and ASP/VBScript. Due to the similarities in concept, ASP is considered PHP's greatest source of competition. The various test cases show PHP/Zend running significantly faster than ASP on identical hardware under Windows NT/SP4 and IIS.
Performance was not the only design issue with Zend. Asked what other design goals he had for PHP/Zend, developer Zeev gave the following list:
Complete platform independence—in both operating system and web server.
Modular design—PHP 4.0 is well split into components that communicate with each other through standard interfaces (compiler, executor, web server abstraction layer, function modules, etc.)
Stability and scalability (an almost direct result of the modular design).
New extendibility through object-oriented (OO) overloading support. For example, PHP 4.0 natively supports OO syntax for accessing Windows COM objects and is likely to support CORBA components in the future.
PHP 4.0 includes a variety of new features. A command-line interactive debugger will be included that supports break points and stepping through scripts. The debugger has not yet been released as of PHP 4.0 Beta 2.
Support for Windows COM objects has also been added, giving developers access to the wide variety of available Windows server components.
Because of the new automatic resource deallocation, resources don't need to be freed within the script, since they are freed as soon as they are deallocated. This is similar to Java's garbage collection. Note that PHP 3.0 will also free resources automatically, but not until after the script is finished processing.
New syntax changes include support for a foreach loop. Additionally, the terms “true” and “false” are now predefined. Pointers can now be implemented allowing two variables to represent the same variable.
New output buffering allows developers to abort a page after processing has begun. This simplifies proper error handling in scripts.
In March of this year, a closed beta was released to PHP developers and a handful of other sponsors. The first public beta of PHP 4.0 was released in July, followed by Beta 2 in August.
Feedback from the first beta release was very positive. The official word from Zeev Suraski on the release date for 4.0: “We'll release PHP 4.0 once it is stable enough for users.” The remaining work is checking all the PHP modules to make sure they're PHP 4.0-compatible. After this is complete, PHP 4.0 should be ready for release. Most likely, this will be before the end of the year.
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
Free to Linux Journal readers.Register Now!
- SUSE LLC's SUSE Manager
- My +1 Sword of Productivity
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- Managing Linux Using Puppet
- Non-Linux FOSS: Caffeine!
- Tech Tip: Really Simple HTTP Server with Python
- Doing for User Space What We Did for Kernel Space
- Parsing an RSS News Feed with a Bash Script
- Rogue Wave Software's Zend Server
- SuperTuxKart 0.9.2 Released
With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide