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Christopher Frenz

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Top Stories by Christopher Frenz

The ability to perform pattern-matching operations on text is a skill that is highly useful to any programmer. Whether you are creating a routine to validate data entered into a form, performing parsing and mining on data sets, or searching for sequence similarities in the human genome, chances are that the ability to construct a regular expression will be of great value to you. A single regular expression can often be used to create the same pattern-matching functionality that would otherwise require a lengthy subroutine. Yet despite these apparent benefits, many .NET developers find regular expressions daunting because they have a syntax based on Perl 5 regular expressions and are thus somewhat different from the typical .NET language constructs. In this article I will discuss the basic syntax of regular expressions and how they operate in order to demystify them... (more)

Using PHP to Enhance Password Security

When dictating password policies to users, it is common for such policies to require that users generate passwords that contain a combination of uppercase and lowercase letters, as well as numbers and special characters. Moreover, it is well established that the strengths of such passwords are further enhanced if the passwords do not in any way resemble dictionary words, since minor substitutions of dictionary words and names are often included in the dictionaries used in dictionary-based attacks and in some rainbow table variants. Thus "D3veloper" would be a less than ideal pass... (more)

The Development of a Perl-based Password Complexity Filter

If you watch the news regularly, it is easy to notice that in almost any given week some company seems to have experienced an electronic break-in or in some other way experienced a form of computer or network compromise. While computer security professionals can help to mitigate such risks via the proper configuration of firewalls, careful crafting of Access Control Lists, the application of updates, and the judicious application of file permission, among other measures, it's important that one of the most fundamental ways of improving the security of a computer or network resour... (more)

Creating Mobile Controls with the Mobile Internet Toolkit

The Mobile Internet Toolkit comes prepackaged with a variety of controls that address the most common mobile computing tasks. However, specialized tasks can arise that these generic controls are not powerful enough to address, or for which they simply fail to meet the requirements. In these cases it is beneficial to develop a custom control that is suited to fulfilling the required tasks. In this article, I will concentrate on developing and implementing such custom controls within a mobile application. The primary focus will not be on creating custom user controls and/or inheri... (more)

Windows for Supercomputers

In late May 2004, Microsoft made the announcement that it was considering entering the High-Performance Computing (HPC) Market, a market that has traditionally been dominated by custom-engineered Unix-based machines. In recent years, advances in technology have made possible the construction of lower-cost computing clusters that utilize off-the-shelf hardware such as Intel- and AMD-based processors. The operating system of choice for these lower-end clusters has been Linux. In fact, this market is representative of one of Linux's strongest footholds. Many in the Linux camp consid... (more)