3. Tim Berners-Lee wrote the first proposal for the World Wide Web in March 1989 and his
second proposal in May 1990. Together with Belgian systems engineer Robert Cailliau, this
was formalised as a management proposal in November 1990. This outlined the principal
concepts and it defined important terms behind the Web. The document described a
"hypertext project" called "WorldWideWeb" in which a "web" of "hypertext documents"
could be viewed by “browsers”.By the end of 1990, Tim Berners-Lee had the first Web
server and browser up and running at CERN, demonstrating his ideas. He developed the
code for his Web server on a NeXT computer. To prevent it being accidentally switched off,
the computer had a hand-written label in red ink: "This machine is a server. DO NOT
POWER IT DOWN!!"
4. The main job of a web server is to display website content
through storing, processing and delivering webpages to users.
A web server is software and hardware that uses HTTP (Hypertext
Transfer Protocol) and other protocols to respond
to client requests made over the World Wide Web.
Every Web server that is connected to the Internet is given a
unique address made up of a series of four numbers between
0 to 255 separated by periods. For example, 184.108.40.206
6. Request a file from web document
(*html, *.gif, etc.)
Find existing thread/process corresponding to the
user's connection, or start new one.
Parse HTTP request, extracting file name and path
of requested file.
Find and retrieve requested file, or return error
Parse response and display in web
browser.Repeat until all files in web
document have been retrieved.
Add HTTP header and send response to user.
Getting IP Address from DNS: In the First step, web browser gets the IP (Internet
Protocol) from domain name. IP address can be received with two methods like as Finding IP
address in Cache and requesting IP address in multiple DNS (Domain Name Servers).
Browser Request Fully URL: Web browser fully aware which IP address website is
located at, so it can send request full URL from server side.
Web Server sends Requested Page: Now web server responds with sending requested web
page toward web browser. If those web pages do not present then appropriate error message will
be display on the web browser. For example – “Error 404 will be display, if your requested pages do
not present”.” Error 401 will be display, if user inserts incorrect credential information such as
username and password.”
8. The document root is the root directory of servable documents
Suppose the site name is www.bloomers.com and the document root is named
topdocs, and it is stored in the /admin/web directory
Then, /admin/web/topdocs is the document directory address
If a request URL is
The server will search for the file named
The server can have virtual document trees
Sometimes a different disk, possibly on a different machine, is used after the original
disk is filled
9. The server root usually has four files/subdirectories
1) One is the code for the server itself
2) conf - subdirectory for configuration information
3) logs - subdirectory to store what has happened
4) cgi-bin - subdirectory for executable scripts
10. Virtual hosts - multiple sites on the same system
Proxy servers - to serve documents from the document
roots of other sites
Besides HTTP, support for FTP, Gopher, News, email
Support for database access
11. A client-server architecture or model is an application network separating
tasks between the clients and servers that live in the same system or
have to communicate through a computer network. The server-client
mainly relies on sending the request to another program to access the
service made accessible by the server. This server runs a few programs
that share the resources with & distribute work among the clients.It is also
known as the networking computing model or client server network as all
requests and services are delivered over a network.
A client-server relationship corresponds to the request–response pattern
and should adhere to the common communications procedure that
defines the language, rules, or dialog patterns used. The client-server
communication adheres to TCP or IP protocol suite.
13. A 1-Tier Architecture:
All client or server configuration settings, UI environment,
data logic, as well as marketing logic are there on the same
system. The 1-tier architecture services are quite reliable but
tough tasks to handle as they have all data in various
variance that will be allotted the complete replication of the
whole work. 1-Tier architecture also has different layers.
For example –Business, Presentation, Data Access layer
using a single software package. Data will be saved on a local
machine. Some applications manage 3 tiers like an MP3
player and MS Office; however, these applications are
presented in a 1-tier architecture system.
14. B 2-Tier Architecture:
In 2-Tier Architecture, the UI is stored at the client machine,
and the database gets stored on a server. The business logic
and database logic are filed at server or client but have to be
well-maintained. Suppose Data Logic and Business Logic are
collected at the client-side, it’s called fat client-server
architecture. Suppose Data Logic and Business Logic are
handled on a server, its thin client-server architecture. It is
In 2-Tier architecture, server and client need to come in the
direct incorporation. Suppose a client provides any input to a
server there must not be any intermediate. It is generally done
for rapid results and to avoid confusion between various
clients. For example, an online ticket reservations application
uses this 2-Tier architecture.
either with BL & DL
BL & DL
15. C 3-Tier Architecture:
It consists of the presentation tier that is the User Interface layer, an application tier
that is a service layer, which performs the detailed processing, and a data tier that
consists of the database server, which stores information. Three-tier architecture can
be split into 3 parts, the presentation layer (or Client Tier), the Application layer (or
Business Tier), and the Database layer (or Data Tier). It works in the following ways:
The Client system handles the Presentation layer; the Application server looks after
the Application layer, and the Server system supervises the Database layer.
BL & DL
16. • Client and server machines need different amount of hardware and
• Client and server machines may belong to different vendors.
• A client or server application interacts directly with a transport layer
protocol to establish communication and to send or receive information.
• The transport protocol then uses lower layer protocols to send or receive
individual messages. Thus, a computer needs a complete stack of
protocols to run either a client or a server.
• A single server-class computer can offer multiple services at the same
time; a separate server program is needed for each service.
17. A Advantages:
• Cost-efficient needs less maintenance cost & Data recovery is made
• The capacity of the Client/Servers will be changed separately.
• Centralized system with data in one single place.
• Clients can be prone to viruses, worms, and Trojans if present in a
Server/uploaded in the Server.
• The server can be prone to Denial of Service attacks.
• Data packets will be modified or spoofed during the transmission.
• Phishing and capturing login credentials and other useful info of
user are quite common and Man in a Middle attack will be
18. A Mail Servers: Email servers can be used for sending &
receiving emails. Different software allows email handling.
B File Servers: They are the centralized location for the files. For
example, cloud services for Microsoft Office and Google docs will
be accessed from your devices, and files that you save from the
computer will be accessed from your phone. In this way, file stores
will be centralized and accessed by multiple clients.
19. EXPLAIN THE CLIENT-SIDE OF WWW
Processing taking place on the users computer:
• On client-side it generally refers to the device through
which the user is accessing the internet.
• A browser is needed to execute the scripts on the machine
i.e. any file with an extension like .js or .html requires a
browser to run.
• Reduces load on the server processing unit. For example,
CDNs are distributed networks comprised of strategically
placed edge servers that enable the rapid delivery of web
content to users across the world.
• A CDN can reduce your server load and speed up your
website by caching your site's static content.
20. • Web server is a program or the computer that
provide services to other programs called client.
• The Web server accepts, approve and
respond to the request made by the web
browser for a web document or services.
• The web server gets HTTP requests and
send HTTP responses.
Web Server Web Browser
• There exist three types of processing
models for web server i.e Process-based,
Thread based and Hybrid.
• Web servers provide an area to store and
organize the pages of the website.
• Example: Apache, Nginx, IIS etc.
• Web Browser is an Application program that
displays a World wide web document. It usually
uses the internet service to access the
• The Web browser requests the server for the
web documents and services.
• The web browser sends an HTTP request
and gets an HTTP response.
• Doesn’t exist any processing model for the
• Web browser stores the cookies for different
• Example: Crome, Brave, MS Edge etc.
A web server is computer software and underlying hardware that accepts requests via HTTP (the network protocol created to distribute web content) or its secure variant HTTPS. A user agent, commonly a web browser or web crawler, initiates communication by making a request for a web page or other resource using HTTP, and the server responds with the content of that resource or an error message. A web server can also accept and store resources sent from the user agent if configured to do so.