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PHP In Business Part 2

By: Keith Hearne
Following on from the last article in which we talked about in business, we take a deeper look at the technology and give a further insight into the benefits of PHP for your business.
1. Efficient Development and Maintenance
PHP can help to quantify the roles between developer and designer, offering a variety of libraries to work with page templates, which introduces efficient development methodology and simplifies maintenance. Developer’s focus on the application logic, and designers can change the layout of a dynamic page without involving the developer or interfering with the program logic, making for faster application development, maintenance becomes easier and both can be handled by separate team members.
2. Faster Time to Market
IT managers and developers demand high productivity from their development environments. PHP is lightweight, can solve complex web development problems quicker and its easily to use in comparison to other, more cumbersome solutions. Programmers familiar with C, Perl, or Java, can get acquainted with PHP in a matter of days, producing small database enabled applications after just one afternoon.
3. Connectivity
PHP offers a broad range of database connectivity, both open source and commercial. The native database access offers better performance and tighter control than layered access methods such as ODBC (which is still available for databases not supported natively). PHP also supports most current Internet standards: IMAP, FTP, POP, XML, WDDX, LDAP, NIS, and SNMP to list but a few. All this from one common tool set, without the need for expensive third party modules.
4. Existing Enterprise Logic
Since version 4.0, PHP supports direct access to Java objects on any system with a Java Virtual Machine available, as well as Distributed COM on Windows. This means a significantly lower Cost of Ownership and enables business to leverage existing technology and develop new applications in an easier way.
5. Portability
PHP has the advantage of being platform independent and can run on all popular platforms, including Linux, Windows, MacOS, and even OS/2. This portability is the key to scalable applications, so there is no need to worry about platform-specific features.
6. Performance
PHP can provides a performance gain and with free add-ons such as The Zend Optimizer from Zend Technologies, can perform on-the-fly code optimizations to enhance the running speed of PHP applications (typically executing 40% to 100% faster).
echnology is getting faster, development is getting quicker and so the methods employed to achieve this must be reliable, robust and fast. If your business requires rapid development, performance, scalability, security and more then PHP is a strong option for you to consider.

PHP In Business (An Introduction)

By: Keith Hearne
One of the Web’s hottest server side technologies at the moment is PHP. Recent studies carried out by Netcraft have found that PHP is in use on over 6% of all Web domains in the world (see http://www.netcraft.com/survey), which is surprising when you consider that a good deal of people, even those in the computer industry themselves do not necessarily know what PHP is. Clearly, the rise of PHP has gone largely unnoticed.
What Is PHP? PHP is an Open Source language developed by Rasmus Lerdorf, a then Toronto-based IT-consultant who unleashed the first version of PHP way back in 1994 and then in 1997, Zeev Suraski and Andi Gutmans, two developers from Israel, rewrote the core engine of PHP and the language parser, turning PHP into a complete programming language.
PHP borrows its language style and syntax from a number of other sources, including C, Java, Perl, and others while its principles are similar to those of Sun’s JSP, or Microsoft’s ASP which can all used to create dynamic web content. For many people with previous programming experience, this means implementing their first Web-based application in PHP is a simple affair, as they already have an implicit understanding of how their program should go together.
Why PHP? There are a number of reasons that would appeal to the decision of using PHP.
* PHP is Open Source. This is very beneficial to PHP’s notoriety, the main reason being cost. How Much? Nothing! You install PHP and away you go, you’re up and running and programming in PHP. Total cost? The time and effort it takes to set it all up. This is what makes this technology very attractive to the hacker mentality that the Internet was built on. Why pay for something when you can get something just as good or better for free?
* PHP performs sophisticated mathematical calculations, provides network information, offers mail and regular expression capabilities, and much more.
* PHP’s strongest feature is its database interfacing capability, supporting many of the most popular database servers on the market, including MySQL, Oracle, Sybase, MySQL, Generic ODBC, and PostgreSQL, to name a few. In particular, PHP’s interfacing capabilities with MySQL (see http://www.mysql.com) perhaps the most powerful database server found on the market today are very impressive with MySQL having its own PHP API.
So with web based businesses such as Amazon, Xoom and Lycos all using PHP, as well as hundreds of thousands small to medium Web sites. Can you afford not to get clued in to PHP?
A simple download for PHP is available at http://www.php.net. Go surf!!!!
(This article is Part 1 of a 2 part series)

ADSL – What is it and do I need it?

By: Shane Dempsey
Let’s face it, in Ireland home Internet access is just too S-L-O-W. If you have a 56 Kbps (Kilo bits per second) modem you’re unlikely to get download speeds above 4 Kilobytes per second (8 bits to a byte and congested networks). Start adding images to web pages and they quickly grow to well over 50 Kilobytes making access quite slow even if common images are stored on your computer or cached. The good news is that the situation will improve and there are faster Internet access methods. ISDN is one of possibility but this is a relatively old technology, fast by comparison with 56K modems.
Asymmetric Digital Subscriber Loop (ADSL) is a much newer modem technology, which has been developed over the last 10 years to provide a broadband (transmission over a wide range of frequencies), always-on connection over an ordinary telephone line, on top of the existing telephone service. As the name suggests, it’s asymmetric and provides a greater downstream capacity (towards the customer) than upstream capacity. The cable linking the Local Exchange or Central Office of the telephone network with the customer’s premises is designed to deliver the 4 kHz of bandwidth needed for the standard analogue voice telephone service but can carry signals at much higher frequencies. Above 20 kHz, the signals are severely distorted. ADSL modems carry the broadband signals at frequencies between 20kHz and 1.104MHz (M stands for Mega or million) and use sophisticated encoding/decoding techniques to overcome the distortion.
The modulation scheme (how data is transmitted over the wire) is constantly adapted to compensate for the distortion at these high frequencies. ADSL modems can theoretically deliver up to about 8Mbit/s downstream and almost 1Mbit/s upstream but the actual transmission rate that can be achieved is strongly dependent on the length and quality of the copper cable. Customers must be within a few kilometers of their local exchange. In general, ADSL modems contain a Public Switched Telephony Network (PSTN) splitter, allowing ADSL and telephone signals to be carried on the same copper pair. The splitter acts as a filter, routing low frequency PSTN signals to the telephone and high frequency ADSL signals into the ADSL encoder/decoder.
Most ADSL operators offer a range of service options. Each option provides varying levels of downstream and upstream transmission rates. Eircom is still carrying out trials on their ADSL service, called I-Stream. Home customers of the service can expect to pay around EUR250 for equipment and setup and around EUR100 per month. Business customers wishing to connect a network of 4 or more users to the web via ADSL will pay about 390 Euro for equipment and setup and a further EUR225 a month. These products offer 512/128 Kbps and 1Mbps/256 Kbps transmission rates, respectively.
This is not the complete story however as ADSL is ‘always-on’ technology. This means that your machine or network is always connected to the Internet. This means that you don’t have to wait 30 seconds or so while your computer dials up and you receive e-mails instantly. The downside is that you absolutely require security software that can act as a firewall to stop from stealing information or tampering with your computer.

Telephony

By: Boris Rousseau
The history of mankind has been greatly influenced by his successes and failures in communicating his perception of the world around him to others. Marshall McLuhan, the Canadian communications expert, argued that the technology of communication greatly affects our understanding of the message to be communicated. “The medium is the massage” [1]
In the developed world, telephony is the dominant communications technology. Over 20% of the world’s population has access to a telephone [2]. Indeed an advanced and reliable telephony network is considered necessary for a nation to consider itself developed. Like most everyday technologies, telephony can seem a like magic. Strictly speaking, telephony involves reproducing sounds a distance. Typically the sounds are those produced by the human voice and are transmitted as electrical impulses over wires in a similar manner to that proposed by Alexander Graham Bell in 1876. Other transmission technologies such as wireless or radio transmission and optical fiber are also widely used but rarely provide the direct connection between the home and the network. This direct connection is often known as the access network or ‘last mile’.
The network itself is made up of a collection of telephony switches or exchanges that are used to route voice data from one telephone to another. Exchanges are the practical alternative to connecting every telephone to every other telephone using a wire or group of wires for each connection. A phone call is a virtual connection or circuit between two telephones that is maintained by the network for the duration of the call and provides a consistent and reliable flow of voice data between phones.
In Ireland the vast majority of home telephones are analogue. This refers to the data transmission method used. Voice data is represented by electrical impulses that are analogues of the voice that produced them. The strength of the electrical signal varies linearly with the loudness of the human voice
that produced it. This is an acceptable method of transmission over short distances. Unfortunately the world is an extremely hostile place for telephone wires and analogue telephony transmissions. There are many factors that can produce small degradations in the signal, cumulatively producing inaudible and unclear reproductions at the other end of the ‘phone line’. To preserve the signal’s integrity over long distances it becomes necessary to represent the voice as digital data. This happens before transmission in the case of digital transmission systems like Integrated Services Digital Network (ISDN) and between or at telephone exchanges for a normal ‘analogue call’. This protects data’s integrity two ways. The level of the signal is sampled at regular intervals and then approximated or quantised by a fixed number within a certain tolerance of the signal’s strength or amplitude. The samples are then transmitted as binary data. Simply put, binary or base-2 data represents numbers using a sequence of 1s and 0s. It is much easier to recover the state of a signal where there are only two possible states at any one time then it is if the state is an analogue of something infinitely variable, like loudness of the human voice. Counter-intuitively it is also possible to transmit binary voice data faster. The information is conveyed in a more elaborate form but is harder to corrupt and can therefore be transmitted faster and using a wider range of transmission technologies e.g. Ultra High Frequency (UHF) radio or optical fiber.
I’ve only provided a brief introduction into the complexity of the communications devices that we take for granted. Mobile phones and the wireless network will be explored in more detail in later columns.
[1] The Medium is the Massage, Marshall McLuhan et al., 1967
[2] State of the World Forum, State of the World Index, 2000

XML

By: Boris Rousseau
You may have heard of HTML (Hyper-Text Markup Language), the underlying format used for defining all Web pages. The beauty of HTML was its simplicity, but it was not very flexible. If people wanted to add new types of markup (e.g. a way of centring all headings) a whole new version of HTML was needed.
XML was developed to avoid this problem. Instead of simply defining one standard, it is a standard for defining standards (i.e. a meta language). As long as you follow the rules, you can define what you like, you just need to make the definitions available as well. So, XML is really nothing more than a standardised system for using a text format for representing structured information (most commonly on the Web). This structured information may contain both content (words, pictures, etc.) and some indication of what role that content plays (for example, book, author, title).
XML stands for eXtensible Markup Lanugage. Each of these words describes an important part of what XML is and what it does.
The first word is Extensible, which gives XML much of its strength and flexibility. In XML, you create the tags you want to use. XML extends your ability to describe a document, letting you define meaningful tags for your applications. For example, if your site contains many library terms, you can create a tag called for those terms.
The second word in XML is Markup. This is the purpose of XML: to identify elements within your document. By marking up your document, you begin to give meaning to the pieces within. You identify the bits and pieces in a way that gives them value and context. And, with extensible markup you can mark up the document in ways that match your needs.
The third word in XML is Language. This states that XML follows a firm set of rules. It may let you create an extensible set of markup tags, but its structure and syntax remain firm and clearly defined. In technology, the term “language” is often automatically appended to the word “programming” as in “programming language”.
IT people often assume that all languages are for programming and for creating a set of actions. But a language is just a way of describing something – be it a program’s actions or a markup definition. Extensible Markup Language is a means of marking up data, using a specific syntax.
All this description justifies the fact that XML is a great way to share information over the Internet, because:
* it is open; XML can be used to exchange data with other user across different platforms in an independent way.
* self-describing nature makes it an effective choice for business-to-business and extranet solutions because of its extensible and markup nature.
* you can share without any prior coordination. Mechanisms in XML allow you to discover the structure of a class of XML documents.
To illustrate this, here is a short example of XML document describing a library:

Charles M. Schulz

As you can see above, an XML document comprises three parts:
* An optional prolog
* The body of the document, consisting of one or more element, in the form of a hierarchical tree that may also contain character data
* An optional epilogue comprising comments, processing instruction (note, there is no epilogue in the above example)
Whether they realize it or not, many people will be coming in contact with XML in the years to come, whether it be that the web page they are reading was actually originally authored in XML, or the menu on their mobile phone was written in XML. In particular business people will find that XML becomes core to the way business computing is done. Already the Irish Tax Office are experimenting with submission of tax returns using a standard format, actually specified using XML.

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