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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.

A Truly Smarter Phone

By: Cathal O’Riordan
In 10 years people will visit museums and marvel at the sheer size and weight of the early generation mobile handsets. Hardly worthy of the term ‘mobile’ by today’s standards, these colossal brutes had limited battery power and user features. For example, the Nokia Mobira Senator, circa 1982, weighed 9.8 Kg. Thankfully, as advancements were made in microelectronics the size of mobile handsets continued to diminish to become the small and sometimes unobtrusive devices we use in our everyday lives.
Traditionally mobile phones have been voice-centric, used mainly for making and receiving calls. Achievable data transmission rates over Global System for Mobile (GSM) networks have made it impractical to offer services like e-mail (with attachments), Internet or video/music streaming but the recent introduction of the General Packet Radio System (GPRS) and forthcoming 3rd Generation (3G) networks make these types of services a reality to customers. Manufacturers of both hardware and software are now facing new challenges, as they endeavour to provide the content-rich environments mobile users have come to expect of their desktop systems.
We are now seeing the latest evolution of mobile handsets with the introduction of the Smart Phone to the mobile market. A Smart Phone is a combination of both phone and Personal Digital Assistant (PDA) in a single device. It offers the capabilities of a traditional mobile phone but in addition allows a user to perform many of the tasks currently available on more familiar systems. Heralded as the Swiss-army knife of portable electronics, these devices boast colour-rich displays, Personal Information Management tools (calendar, e-mail, appointments etc.), Internet Browsing, Multimedia Messaging Service (MMS), document/spreadsheet editing software, personalisation (ring tones, colour schemes, images etc.), streaming media, games and digital image capture all packaged in a small convenient unit. This level of functionality comes at a price though. Smart Phones are expected to be marketed as premium priced handsets fetching anywhere between EUR200 and EUR800.
The Smart Phone market is becoming very competitive with leading companies like Microsoft, Palm, Sony Ericsson, Motorola, and Nokia all entering the arena. Each company is shaping the industry with the expertise it brings from its indigenous marketplace. Software manufacturers such as Microsoft and Palm produce the platforms or operating systems, which are then licensed for distribution with phones from equipment manufacturers. For example, Microsoft, in association with UK based mobile manufacturer Sendo (http://www.sendo.com) is set to launch its first mobile phone operating system called Smartphone 2002 (the actual phone will be called the Sendo Z100). Code-named “Stinger”, it is similar in appearance to the accomplished Windows PC platform and will thrust Microsoft into yet another popular consumer market. However, Smartphone 2002 has been fraught with delays and is not expected for release until early 2003. Other leading competitors such as Symbian and Palm OS have already launched their Smart Phone platforms and have been adopted by both mobile manufacturers and consumers alike. Symbian has been a popular choice amongst the latest phones from Nokia and Sony Ericsson. The Nokia 7650, 3650 and Sony Ericsson P800 all exploit the rich feature-set of the Symbian platform.
Nobody is certain who will be the emerging victor in the Smart Phone market. Each mobile manufacturer is backing the platform they think is a clear winner, but in this new and unpredictable environment no one is a safe bet. Industry sceptics fear that users will be unable to use the features of a Smart Phone in the way they were intended because of the relative immaturity of high-speed mobile networks. Although the underlying principle of a Smart Phone is to operate both with and without the presence of a connection to the Internet or network, for most features this is a necessity. What is apparent though is the benefit of the Smart Phone to the consumer. Users will now be able to proclaim true mobility where the applications and services they once associated with their PC or laptop will soon be available from a mobile phone.

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