Click on me, if you just want to see the magazine

Date: Wednesday, 8 August 2001
Ed: Billatnapier
Source: Chapter 5, Mastering Computing
Price: £12 (UK)/ $16 (US) - Sorry about the increase in price
This is a special edition of the Jargon Buster, and presents some of the most asked questions relating to IT terms. More information can be found in Mastering Computing. [Show essay][Previous edition][Next edition]
Question: I've just had a lecture on the WWW and the Internet, and my head is spinning (not literately, of course). I counted 20 acronyms that I have got a clue about. Can you help? They included HTML, HTTP, VB Script, ASP, PHP, CGI, PERL, CSS, RSA, DHCP, TCP/IP, IP, and many more.
Oh dear. Computing is a difficult enough learning the principles, without have to try and understand some of the term. If you're ever struggling with a term, just put your hand up and ask what it means.
Well here goes. I assume that you don't just want to know what the acronym stands for, so I'll try and give you a quick overview of the terms. Well, HTML is the standard com-puter language that is read by a WWW browser, and contains special tags which iden-tify the format of the WWW page, such as text contained with <B> and </B> will be shown as bold. HTML is fine for basic formatting, but it is not so good at getting user interaction, thus VBScript (Visual Basic) is a simplified form of Visual Basic (which is the most popular programming language in the world) and is used to provide some basic func-tions, such as time() to display the current time. VB script integrates into HTML, and can hide itself from WWW browsers by imbedding it in-between the <SCRIPT LANGUAGE= "VBSCRIPT"> and the </SCRIPT> tags.
sub myheader_onClick
myheader.Style.Color = "BLACK"
end sub

TCP/IP. What can you say about TCP/IP? It's one of the most successful inventions of all time. It has allowed computers, and any electronic device to connect to each other over the Internet. The IP part allows for addressing on a word-wide basis, while the TCP part allows for the data to be split into seg-ments, each which are uniquely identified so that the receive can build them back into the transmitted data. You can think of TCP a bit like a write sending his manuscript to the publisher. On each chapter that he sends to marks it with the Chapter number, and the page numbers. Then he puts each chapter in a parcel and addresses it (which is equivalent to the function of the IP protocol). The postal service will then routes the parcel to eventually find the destina-tion (these are equivalent to routers on the Internet). When the publisher receives the parcels they will be opened-up and the chapters will each be reordered in the correct order (just as TCP does). When received the publisher will phone-up the writer to say that they have received the parcel. This provides an acknowledgement to the writer that his manuscript has been received correctly (not that the postal could not guarantee that the manuscript had been read, and all they could say was that the parcels had been delivered to the right address). This ac-knowledgement is also part of the TCP protocol, and allows for data to be acknowledged.
Client-side or server-side includes. What?
HTML is the standard language which is used to present WWW page, and is interpreted by the WWW browser. Unfortunately HTML is a rather limited language, and can only really present static information, and is not good at getting user interaction, thus need languages have been added to HTML to enhance it. Typically this is to process user information, or to respond to user events (such as mouse clicks, or text input). The place where the processing of the additional script defines whether it is a server-side include or a client-side include. If the WWW browser processes the script, then it is a client-side include, otherwise it a server-side include. Typical client-side includes are VBScript and JavaScript. Typical server-side includes are PHP and ASP.
Okay. I've explained HTML and VBScript (look two pages back), so I'll continue. ASP is similar to VBScript, but rather than the browser processing the script, the WWW server actually does it before it sends the page to the WWW browser. ASP is a Microsoft technology and will typically only run on a Microsoft server (such as with an Microsoft IIS server).
ASP pages are named with an asp file extension (such as default.asp). An example is:
<B>Current time is <%=Time()%> </B>
which will display the current time. When this is sent to the WWW browser it will have the Time() function expanded into HTML code, such as:
<B>Current time is 10:35pm</B>
for which the WWW browser will display as:
Current time is 10:35pm
ASP is a Microsoft technology for server-side includes in HTML pages, whereas PHP is a UNIX equivalent, and typically runs on an Apache WWW server.
Let's continue with CGI and Perl. A CGI program is one that is called from a WWW browser. These can be written in many languages, such as Visual Basic, C++, Java and Perl. Visual Basic, C++ and Java normally require to be compiled into an ex-ecutable form for it to run on the server. Perl is different in that it is a scripted language, and does not have to be compiled before it is used. Normally Perl programs perform some sore of system function, such as getting information on the cur-rent WWW connection. They must be kept in a secure way so that external users cannot gain access to the server, thus they are placed in a special directory called the cgi-bin. Scripts placed in this place are allowed to gain access to the system. An example Perl program to show the IP address of the user is:
print "Content-type: text/html","\n\n";
print STDOUT "\n";
$remote_addr = $ENV{'REMOTE_ADDR'};
print STDOUT "<P>Your IP address is: ";
print STDOUT $remote_addr;

Another particular problem with HTML is that it is not very good at precisely defining text format, especially between different types of browser. Thus the CSS standard has been defined. This involves including a CSS file in the HTML page, which contains definitions for the text styles used in the page. For example to define the first header (H1) style:
{font: bold 16pt Verdana, Arial, Helvetica, sans-serif; background: transparent; color: #000000}
which defines the header style (H1) is Verdana font, of 16 points, and black. Thus <H1>Hello</H1> will become:


So why choose server-side or client-side?
Well a server-side include is better for compatibilty with the WWW browser, as it converts the additional script into standard HTML. For example in ASP:
would be processed as an ASP script (as it is contained with <% and %>), and converted to the HTML code:
<P>Thur, 5 Oct 2001</P>
Thus it does not depend browser version. With client-side include the code is processed by the browser, thus it depends if the browser can actually process the script. Fortunately now most browsers are fairly compatible with the client-side includes, but you can never be too sure how different browser versions are going to present the page.
So what about RSA, DHCP, TCP/IP and IP addresses? Well RSA is the encryption technique which allows a user to generate to encryption keys: one public and one private one. The public one is advertised to anyone who wants to send the user an encrypted message. Once the message has been encrypted with the public key, only the private key can then decrypt it. The great advantage of public-key encryption is that you can use the same public key for all your messages.
Every computer (or node) on the Internet requires a unique address, which is known as an IP address. An example IP address is This address identifies the loca-tion of the computer. Devices could routers are used to pass information about the location of destination IP addresses. An IP address can either be permanently assigned to a computer, or they can be allocated to them dynamically, when they required the IP ad-dress, with a DHCP server which contains a table of IP addresses. This table could be generated from a pool of addresses, or could be based on the physical address of the network adaptor. This gives enhanced security.
DEAR JARGON-BUSTER. What's the things that have united the World?
TCP/IP protocols. Which allows global communications using the Internet. It is a relative new comer to the Top 10 and went straight to No. 1.
The Internet. Which now provides a global infrastructure that has no respect for politics, borders or race.
The Telephone. Which before TCP/IP was easily in first place, but now takes third place to TCP/IP and The Internet as its importance is now reducing as it faces extensive competition from the Internet (especially from Voice Over IP) and e-mail.
Air travel. Which has made the world a much smaller place, in terms of traveling time.
RFC822/823. Which defines the format of e-mail messages. MIME should also get a mention here as it allows for the attachment of many types of content to an e-mail message.
Television. Within a fraction of a second information from around the world can be transmitted to virtually anywhere. At one time events would take days or weeks to report, but which time lives my have been lost. These days very little can be hidden from the camera.
The United Nations. Sometimes it works, other times it doesn't, but at least it is there, and the world should be a safer place because of it.
Trans-continental cables and satellites. Which have allowed the countries of the world in interconnect.
Personal Computers. Which allow the interconnection of virtually any computer on the Internet to any other computer. Wow!
HTTP protocol and WWW browsers. Which have allowed the distribution of information around the world.