Sometime in the mid 1960s, a bunch of geeks at AT&T's Bell Labs decided it would be fun to create a new
operating system called Multics. (This was no small task, because computers at the time were about the size
of a football field and two stories high.) Multics fizzled in 1969 when Bell cut the cord, but some of the
geeks continued work on what became known as UNIX; and it became wildly popular inside AT&T.
Since AT&T was not allowed to sell computer software at the time,
it gave away UNIX (complete with
source code) to any educational institution. AT&T produced new
versions of UNIX called System III and
System V in the early 1980s, but all the while, geeks at the University
of California at Berkeley and other
places were busy hacking away on their own versions of Unix based on the
AT&T code. Some cross-pollination did occur, but there are still
significant differences between the Berkeley (commonly called
BSD Unix) and AT&T flavors. In the early 1990s, AT&T sold UNIX
to Novell, which was bought by
Digital Equipment Corporation, which sold it to SCO (Santa Cruz
Operation) in 1995. For the next 15 years,
SCO then tried (with little success) to sue just about everyone,
claiming that Linux or some variant
of UNIX, or a product based on them, violated their copyright and/or
licensing terms. SCO now teeters on
the edge of bankruptcy, after a court ruled in 2010 that Novell is the
owner of the UNIX copyrights.
So how does this affect Linux? Much of the legal wrangling was over whether or not snippets of the
original UNIX code found their way into Linux, and if so, was it a legal violation of any sort. Novell
seems to have put this to rest by stating "We don't believe there is Unix in Linux" and pledging
not to sue anyone over UNIX or Linux ownership issues.
Today, there are now lots of Unix variants sold or given away by many different companies and
universities. While these various flavors can make it difficult to write portable software, efforts to
standardize Unix (two of the more notable ones being POSIX and COSE) offer hope for greater
compatibility in the future.
Like any operating system, Unix has some cryptic commands and less-than-intuitive aspects. (Three of the
most important Unix commands have the peculiar names cat, grep, and awk .) Either serious hallucinogens
or a warped sense of humor came into play at some point in the creation of Unix. I don't let this bother me,
though, taking comfort in my favorite platitude: "Unix was written by geeks on drugs." Seriously, though,
Unix is really no more difficult to learn than DOS or Windows--it's just different.
Can Linux Replace Windows?
Until recently, running Unix meant investing in a powerful workstation
that cost megabucks. Linux changes all that, because it's a complete
version of the Unix operating system (software that controls the basic
functions of the personal computer) that
runs on ordinary personal computers. The added fact that it's freely
available and "open source" makes it all the more attractive.
Linux is perfect for people who want to operate their own low-cost
Internet servers, and it's robust enough to satisfy the needs of many
Internet service providers. Linux is a multiuser and multitasking
environment, and it can access huge amounts of me
mory (gigabytes) and huge amounts of disk storage space (terabytes).
Linux offers virtually everything that Windows has been promising for
years and may not deliver in a truly stable form for some time to come.
Don't make the mistake of assuming that Linux is some kind of watered-down or underpowered Unix for
the masses. Linux is Unix. POSIX certification (compliance with the industry standards for Unix) makes it
official that Linux can do everything that a Unix system is supposed to do. The only difference is that Linux
works on a personal computer, whereas other versions of Unix run on larger workstations or mainframes.
Linux is also being taken very seriously by the computer industry, with new Linux-compatible versions of
popular software packages being announced every month. The Apache Web server software running on
Linux platforms powers about half of all Web sites today. Even more telling, Microsoft considers Linux a
major threat to its Windows empire.
What Is Linux?
In the early 90s, a geek named Linus Torvalds at the University of Helsinki in Finland thought it would be
fun to write a Unix kernel from scratch. He called it Linux, and it was cool but pretty much useless without
all the utility programs needed to make it a complete operating system. At the same time, Richard Stallman
and his pals at the Free Software Foundation were writing a bunch of freeware Unix utilities collectively
known as the GNU Project. It was cool but pretty much useless without a kernel to make it a complete
operating system.
News of Linux spread quickly over the Internet, and many other Unix programmers joined the effort to
enhance it. What we now know as Linux is a combination of Torvald's Linux kernel, the GNU Project
software, and some other nifty software bit and pieces developed by programmers from all around the
world.
Today Linux is a complete and reliable implementation of the Unix operating system, with the following
notable features:
32-bit or 64-bit operation (it uses all the speed and power of your CPU)
Virtual memory (it can use all of your system's RAM)
Full support for X Windows (Unix's standard graphical user interface)
TCP/IP networking support (allowing connection to the Internet)
GNU software support (including a huge amount of free Unix software from the GNU Project)
Linux was written totally from scratch
without using any of the original AT&T UNIX code. (Throughout this site, UNIX refers to the original
trademarked UNIX project invented by AT&T. The term Unix is used here as a generic term for other
variants of the operating system.)
Because of that (and because the author is a nice guy), Linux is
free. You can obtain the source code, modify, sell or give away the
software so long as you provide full source code and don't
impose any restrictions on what others do with it.
For a computer to do anything useful, it needs both application software (programs you use) and an
operating system (programs the computer uses). The operating system sits between the physical hardware
that makes up a computer (the monitor, keyboard, CPU, hard drive, and so forth) and the end-user software
that people use to process documents, play games, and all that good stuff.
We commonly think of the CPU as the brain of a computer, but in reality, it can't do much besides crunch
numbers and move data around in the computer's memory. The job of the operating system (OS) is
twofold:
To work with computer hardware to process user requests by
interpreting keystrokes from the keyboard,
displaying text and images on the screen,
storing files on the hard disk,
sending documents to a printer,
communicating over a modem.
To manage the application software's use of memory (RAM) and processor time.
If you've used a multitasking environment like Windows or a multiuser mainframe system, you've seen the
concept of "time-slicing" in action. While your computer has only one CPU, which can do only one thing at
a time, the OS can make it seem like several people or programs are using the CPU simultaneously.
Similarly, even though the real memory (RAM) is shared by all running applications, the OS can make it
seem like you have it all at your disposal, all the time, by sharing it between applications--using a
technique called paging.
The OS time-slices by giving one user or application exclusive use of the hardware for a brief instant, and
then doing the same for the next user or application. On systems with adequate horsepower, this approach
works so that you never even know about that little game of round-robin going on behind the scenes. On a
wimpy computer or a mainframe with too many users, it's toe-tappin' time for everybody.
. What is JSP ? Describe its concept. 2 . Explain the benefits of JSP? 3. Is JSP technology extensible? 4 .Can we implement an interface in a JSP? 5 What are the advantages of JSP over Servlet? 6. Differences between Servlets and JSP? 7 . Explain the differences between ASP and JSP? 8 . Can I stop JSP execution while in the midst of processing a request? 9. How to Protect JSPs from direct access ? 10. Explain JSP API ? 11. What are the lifecycle phases of a JSP? 12. Explain the life-cycle mehtods in JSP? 13. Difference between _jspService() and other life cycle methods. 14 What is the jspInit() method? 15. What is the _jspService() method? 16. What is the jspDestroy() method? 17. What JSP lifecycle methods can I override? 18. How can I override the jspInit() and jspDestroy() methods within a JSP page? 19 . Explain about translation and execution of Java Server pages? 20 . Why is _jspService() method starting with an '_' while other life cycle methods do not? 21. How to pre-compile JSP? 22. The benefits of pre-compiling a JSP page? 23.How many JSP scripting elements and explain them? 24. What is a Scriptlet? 25. What is a JSP declarative? 26. How can I declare methods within my JSP page? 27. What is the difference b/w variable declared inside a declaration and variable declared in scriplet ? 28.What are the three kinds of comments in JSP and what's the difference between them? 29. What is output comment? 30. What is a Hidden Comment? 31. How is scripting disabled? 32. What are the JSP implicit objects? 33. How does JSP handle run-time exceptions? 34. How can I implement a thread-safe JSP page? What are the advantages and Disadvantages of using it? 35. What is the difference between ServletContext and PageContext? 36 . Is there a way to reference the "this" variable within a JSP page? 37 . Can you make use of a ServletOutputStream object from within a JSP page? 38 .What is the page directive is used to prevent a JSP page from automatically creating a session? 39. What's a better approach for enabling thread-safe servlets and JSPs? SingleThreadModel Interface or Synchronization? 40. What are various attributes Of Page Directive ? 41 . Explain about autoflush? 42. How do you restrict page errors display in the JSP page? 43. What are the different scopes available fos JSPs ? 44. when do use application scope? 45. What are the different scope valiues for the ? 46. How do I use a scriptlet to initialize a newly instantiated bean? 47 . Can a JSP page instantiate a serialized bean? 48.How do we include static files within a jsp page ? 49.In JSPs how many ways are possible to perform inclusion? 50.In which situation we can use static include and dynamic include in JSPs ? 51.Differences between static include directive and include action ?
JSP (Java Server Pages) and ASP (Active
Server Pages) are two of the commonly used server side scripting
languages that are used today in web development. ASP was created by
Microsoft as part of its IIS
that provides the user with tools needed to create a web site on his
Windows computer. It can be considered as free as ASP itself does not
cost money, but the fact that you need Windows means that you are still
going to spend money. JSP was created by Sun Microsystems as an
extension to Java.
Despite having the same task, JSP
and ASP achieves their tasks in different ways. ASP code are
interpreted on the fly each time it is accessed while JSP pages can
either be interpreted or compiled into a servlet. This means that JSP
pages actually takes a little bit longer to load because it needs to be
compiled first. But after it has loaded, it would actually perform
faster just as long as the code does not require any changes. Once the
code changes, it needs to be recompiled which takes longer. In cases
where code changes happens very often to the point that the performance
deteriorates a lot, the coder can opt to have his pages interpreted on
the fly just like ASP with the more or less the same level of
performance. JSP coders also have a choice of either compiling into a
Java servlet, which are still platform independent, or into the
operating system’s native bytecode.
As of today, most web developers are
using either JSP or the improved version of ASP called ASP.NET. For
people who are using a web server that’s running Microsoft Windows,
using ASP or ASP.NET is already a given. Those who use open source
software like Linux can choose between a few options that are either
free or not. Most people use other open source software like PHP while
JSP stands a distant second.
Summary:
1. JSP and ASP are both server side scripting languages
2. JSP is from Sun Microsystems while ASP is from Microsoft
3. ASP costs money while JSP is free.
4. ASP code is interpreted while JSP code is compiled at run time
5. JSP code can run faster than ASP if there are fewer changes
6. Majority of Windows users use ASP while users of open source operating systems like Linux use JSP among others.
Before I get started, you should know that HTML code almost always uses beginning and ending tags. These tags surround the text that will be affected by the code.
A beginning tag is generally a word surrounded by brackets. The closure tag is surrounded by the same brackets but with a forward slash right after the opening bracket.
For example, if you want to bold a portion of a sentence, then you would use <b> for the opening tag and </b> for the closing.
Let’s say you want to bold the word "Hello!" in the sentence below. Then your HTML code would look like this:
<b>Hello!</b> My name is Carla.
The output would be:
Hello! My name is Ajitesh.
Only the word "Hello!" is bolded because the tags surround that word. If you wanted to bold the entire sentence, then you would have put the closure tag, </b>, after the word "Ajitesh". Be sure to always include your closing tag because if you forget, your entire page will be affected by the tag.
You can apply this same concept to many other HTML codes. Here are several of the basics...
Here you will see a sample HTML page with the basic structure.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<html>
<head>
<title>Title that is displayed at the top of your web browser and also used as the title by many search engines</title>
<meta name="description" content="10-15 word description of your site read by some search engines">
<meta name="keywords" content="main keywords of your site separated by commas. Read by some search engines">
</head>
<body>
<p align="left">
This is my new web page. I hope you like it. Please come back and visit again. If you need help creating your web site visit <a href="http://www.2createawebsite.com">2 Create a Website.com</a>.
</p>
</body>
</html>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The <html> tag just tells the browser where the HTML starts. It is not necessary to include this tag to get your page to show.
The <title> tells your browser the title of the page and you’ll see this text at the very top of your web browser. This is also used by most search engines when indexing your page. Whatever text you have here will be title of your site when displayed in the search engines.
The <meta name> information is also somewhat useful for some search engines. They may use whatever is in your "description" tag to describe your site. Others may randomly take an excerpt of the <body> of your page for a description of your site. The keyword tag may also be helpful with your ranking in some engines. Insert 3 or 4 of your main keywords or keyword phrases separated by commas here.
A few years ago, the <meta name> information was quite crucial in getting a top listing with the search engines. However, things have changed drastically with the explosion of so many new sites and the fact that many people abused it. I would still recommend using these tags but don’t expect to get a top ranking because of them.
The body of your site should be included inside the <body> tags.
Need Help With Your Design?
I have some pretty cool, FREE HTML templates you can download. Just select the design you want, download the files to your desktop, edit them on your PC to start designing your site.
Hyperlinks are links that take you to another page or web site. You create them by using the code below:
<a href="http://www.thepage.com">Name of link</a>
The link would appear as, Name of link
Open Links in a New Browser Window
If you don’t want people to leave your site completely when they click on links to other sites, you can set the link to open up a new window. The "target" attribute allows you to do this:
<a href="http://www…… "target="_blank">
Absolute vs Relative URLs
URL is another name for a web site address and stands for Uniform Resource Locator.
There are two different types of URLs you can use to link to various pages, absolute and relative.
Absolute URLs
Absolute URLs include the complete path to the file’s location, including the names of all the directories and subdirectories.
Let’s say you have a folder inside your web site's root directory called "music" and you want to link to a page inside the "music" folder called brahms.html.
If you don’t want to ever have to worry about going back and editing your hyperlinks if your site structure changes then relative URLs are the way to go.
Relative URLs are more or less like shorthand that tells the browser to go backward one or more directories to find the file.
Let's say you're on the page we referenced above, brahms.html (located in the "music" folder) and you want to link back to the home page: (http://www.yoursite.com/index.html)
Using a relative URL, you would tell the browser to go back 1 directory by using the dot-slash method.
<a href="../index.html">Home</a>
The two dots followed by a slash instructs the browser to go up 1 more level to get to the main (root) directory.
Changing the Hyperlink Colors
The default color for hyperlinks on an HTML page is blue, but you can change it to whatever color you'd like by using the link code inside the <body> tag. Here's an example:
<body link="green" vlink="yellow" alink="purple">
In the above example, hyperlinks will be green, links that have already been visited will be yellow and active links will be purple. (An active link is one that has just been clicked, so for a split second the link will change colors as the mouse activates it).
Creating Email Links
Creating email links are just as simple. All you need is the "mailto" function to get this to work properly:
If you want to create a link that will take the visitor to another section of the same page (rather than a new page or site), then you can create an anchor link. There are two steps to this process:
1) First, go to the place in your HTML code where you want the anchor to go. This is the spot on the page that the browser will move to when a person clicks on the link.
Insert the code <a name="name1">This is the Text Where the Anchor Will Land</a> "name1" is just the name of the anchor I chose. You can all it anything you want.
2) Now to link to that section of the page, use the hyperlink code:
<a href="#name1">click here</a>
Basic Table Tags
The three most important tags for tables is the opening table tag, <table> and the table row and table data tags - <tr> and <td> respectively.
The <tr> tag represents a row for the table
The <td> tag represents a cell inside the row.
Now, with that in mind, let's create a simple table:
<table>
<tr> <td>A</td> <td>B</td> <td>C</td> </tr>
<tr> <td>X</td> <td>Y</td> <td>Z</td> </tr>
</table>
And this is what the table would look like published:
A
B
C
X
Y
Z
Notice that by looking at the code, you can tell how many rows and columns are included just by looking at the code. The two opening <tr> tags indicate two rows and the three opening <td> tags on each line represents three data cells (or three columns).
Adding Table Borders
Adding a border simply involves inserting the border attribute to the opening table tag. So in the above table the code would be adjusted accordingly:
<table border="2">
<tr><td>A</td> <td>B</td> <td>C</td> </tr>
<tr><td>X</td> <td>Y</td> <td>Z</td> </tr>
</table>
Notice the "2" represents the thickness of the border. If you had set it to "0" then there would have been no border at all. If you wanted it very thick then you could set it to 8, for example. So now your table will look like this:
A
B
C
X
Y
Z
Changing a Table's Border Color
You can change the color of a table border by simply adding the bordercolor attribute.
<table border="2" bordercolor="red">
<tr><td>A</td> <td>B</td> <td>C</td> </tr>
<tr><td>X</td> <td>Y</td> <td>Z</td> </tr>
</table>
And here's what it would look like...
A
B
C
X
Y
Z
Adjusting Table Cell Spacing and Cell Padding
You can increase the space within the table cells and the space between the cells by using the cellpadding and cellspacing attributes.
The cellspacing attribute adjusts the space between the cells and cellpadding adjusts the space within (around) the cell.
See how setting the cellspacing attribute to "10" drastically increased the spacing between the cells, and the cellpadding attribute set to "3" added a little of space within each individual cell.
Specifying a Table Width
You can specify the width of a table by using either a percentage or a pixel width.
<table width="100%" border="2">
<tr><td>A</td> <td>B</td> <td>C</td> </tr>
<tr><td>X</td> <td>Y</td> <td>Z</td> </tr>
</table>
Since the width is set to 100% that means the table will take up 100% of the screen and the columns in the table will be adjusted evenly. Here's what it would look like.
A
B
C
X
Y
Z
As we mentioned, you can also set the table width using pixels instead of percentages. So instead of setting it to 100%, you could set it to 300 pixels:
<table width="300" border="2">
<tr><td>A</td> <td>B</td> <td>C</td> </tr>
<tr><td>X</td> <td>Y</td> <td>Z</td> </tr>
</table>
The table would look like this:
A
B
C
X
Y
Z
Setting Column Widths
Sometimes you may not always want your columns to be the same size. If this is the case, you need to set values on your table data <td> cells. Again, you can set them by using percentages or pixel widths.
See how the column width for the first column in both rows is set to 70%. Notice there is no value set for the other 2 columns. If you do not set a value for the remaining columns, their width will automatically be adjusted to take up the remaining space and they'll share it equally.
Since the table width is set to 300 pixels, and the first column is instructed to take up 70% of those 300 pixels (roughly 210 pixels), the other 2 columns divide the remaining 30% of the table (roughly 45 pixels a piece).
You could also have expressed the column widths of this table in pixels instead of percentages. The code would have looked like this:
See how the width of the columns in each row add up to 300 (210 + 45 + 45) -- which is the width of the table.
What's the Difference Between Using Percentages and Pixel Widths
Many people prefer to express their table width and column widths in percentages because that will ensure that the table takes up the same amount of screen no matter how big or small the screen resolution is.
If someone is using a 21 inch monitor to view your site and you have a table width set to 300 pixels, the table will show up very small on their screen. However if you set the table width to 70%, it will take up 70% of the screen no matter what size the person is using.
So it's really up to you to decide what's the best layout for your tables.
Specifying a Table's Height
You can also set the table height by adding the height tag to the table code.
See how the first column is aligned to the center? You can also right align the columns by using the align="right" inside the <td> cells.
Vertically Aligning the Content Inside the Table Cells
So far we've kept the table cell alignment at the default, which is the middle. Notice in the above table that the A, B, and C are all three aligned in the middle of their cells. Well you can change their alignment to either top, bottom, or middle by using the valign (which stands for vertical align) tag:
I've set the table height to "250" so the alignment would be more noticeable. Notice that the A in both rows are aligned to the top. You can also align to the "bottom" or the "middle".
Creating a Left Navigation Layout With Tables
As we mentioned earlier, most left and right navigations are created using tables. All you do is create a table with one row, two columns and no border. Then align both of your columns to the top (using the valign tag) so your text will start in the top of the columns, not the middle. Depending on if you're going to have a right or left navigation, you'll make one column significantly smaller than the other.
Notice I set the border to "0" but it's still showing in the example. I just did that to show how the layout would look. If you set your border to "0" you won't see any lines around your table.
So there ya have it! That's a general overview of tables. There's so much more you can do with them, but if you can understand the basic layout, you'll be able to do so much with the design of your web site.
Once you have the image you want to use you can insert it into your web page.
Next you’ll need to do is upload the graphic to your web server. Your web hoster will either provide the environment for you to upload your images or you'll have to use an FTP program.
When you upload the graphic, make sure you pay attention to what folder you’re putting it into because that will affect how you write the HTML.
Let’s say you upload the graphic called "apple.gif" to your "images" folder on your web server. The image folder is located inside your "root" directory.
Your HTML code will look like this:
<img src="images/apple.gif">
Now let’s say you have uploaded the graphic to the "fruit" folder/directory that is located inside of the images folder then the code would appear as:
<img src="images/fruit/apple.gif">
The Alt Tag
If you want text to pop up when you run the mouse over the graphic, then you need to add the alt tag.
<img src="images/apple.gif" alt="This is my apple">
Specify Height and Width
If you want to adjust the height and width of the image then you need to use the height and width tags:
<img src="images/apple.gif" alt="This is my apple" height="100" width="150">
It is recommended that you always include the height and width of your images because it makes your pages load faster.
Adding a Border
To add a border to your image need the "border" attribute. It’s very simple:
<img src="images/apple.gif" border="5"> The 5 represents the thickness of the border. The higher the number, the thicker the border. The number 0 is equivalent to no border. Or you could just leave the border attribute out if you do not want one.
Multiple Attributes
Let’s say you want your graphic to have a border of 2, be 100 x 250 pixels (height x width) and have an alt tag:
<img src="images/apple.gif border="5" height="100" width="250" alt="This is my apple">
Please note that it does not matter what order you put the attributes in (border, alt, etc.). Just make sure you do not leave out any of the punctuation.
"Help, My Graphic Won’t Show!"
If your graphic does not show up and you receive the "broken image" icon, check the following:
Make sure the file is uploaded and is actually in the directory you are pointing to in your HTML code.
Check the case of the actual filename. If you saved the file as "APPLE.gif" but typed "apple.gif" in the HTML code then the image will not show. Case does matter.
Check your HTML code and make sure you have included all the punctuation.
Creating a Clickable Image
Linking images is helpful if you have buttons or banners on your site and you want the visitor to be taken to another web page or site when they click on the image. To accomplish this, use the following code:
If used properly, backgrounds can really enhance your site. If used incorrectly, they can make your site very difficult to read.
If you plan to use a "loud" background that you think is cool, be sure to keep your visitors in mind. Even though you may love it, it may be distracting for the average visitor and you certainly do not want a background that takes away from your text.
In general, try to use light backgrounds on dark text.
To insert a background color on your web page, use the following code INSIDE your <body> tag:
<body bgcolor="red" >
You can specify any color, or you can use a hex value .
Inserting a Background Image
If you want an image for your background then you would use the background and image tag together:
<body background="images/weave.gif">
Keeping in mind that "images/weave.gif" is the location of the graphic. So you’re telling the browser that the graphic is located in your images folder off the root/main directory. You can also use the absolute path to your image. For example,http://www.yourdomain.com/images/weave.gif
Hex values are used for generating colors other than the standard reds, blues, greens, yellows, purples, etc. As you learned above, to specify a purple font you just use the tag <font color="purple">.
But HTML doesn't understand colors like "sky blue" or "pea green" so if you want these kinds of colors, you need to specify a hex color value.
The hex color code chart below will give you the HTML code you need for your desired colors...
1. Drag the bar on the "Hue" selector to generate the desired base color.
2. Next double click inside the Brightness/Saturation grid to activate the cursor. Drag it until the desired brightness is achieved.
The "Swatch" bar shows you the final color result.
3. The Hex Color Code is generated at the bottom of the grid. Simply copy and paste the code into your page.
To indent your text about an inch to the right, simply use the open and closing <blockquote> tag around the text you want to indent.
<blockquote> This text will be indented indented </blockquote>
See how the code makes the text in the paragraph below behave:
sample text sample text sample text sample text sample text sample text sample text sample text sample text sample text sample text sample text sample text sample text sample text sample text sample text sample text sample text sample text sample text
Horizontal lines are great for breaking up paragraphs of text or separating sections of your page.
To create the standard/default horizontal line, you'll just simply insert the <hr> code. This will create a line that looks like this:
Setting Horizontal Line Width, Size and Color
To set the width of your line, simply add a "width" attribute. For example, <hr width="250"> will create a line that is 250 pixels wide. See below...
You can also set the size of the line by inserting a value. So if you wanted a line that is 250 pixels wide and 6 pixels thick, you'd use the following code:
<hr width="250" size="6">
This will produce the line below:
Lastly, you can control the color of the line by inserting the color attribute:
<hr width="250" size="6" color="blue">
You may also use hex colors to define the color of the line.
