Client server technology main

Client Server Technology

UNIT -1

Definition Client requests to the server for data or

information Server serves the data or information Fulfils the requirements of the client &

sends the results back to the client Client performs some logical operations

Definition Client Server Computing (CSC) is that Server Operating

System (OS) accepts requests for data from Client Operating System & returns the results(services) to the Client.

Client manipulates or calculates data and presents the results to the user.

What is Networking?

Connecting computers so that they can share files, printers, applications, and other computer related resources.

Advantages:- File server Network printer Application servers Centralized servers

Different types of networks Local Area Networks(LAN) Wide Area Networks(WAN) Metropolitan Area Network(MAN) Internet

Different types of Networking Peer-to-Peer Networking Workgroup Networking Server-based Networking Terminal-based Networking

History 1969, the Department of Defence USA built

ARPANet(Advanced Research Project Agency). For sharing of data research centres. ARPANet started with just 4 computers on the network

University of

UTAH – Great

Salt Lake City

University of California - Santa Barbara

Stanford Research

Institute – California

University Of Los Angeles

History ARPANet converted into:

-MILNET – Military Network – which was only for the military network.

New smaller ARPANet, which had the non military sites. 1971, 2 dozen sites attached to ARPANet. 1972, 40 different sites attached to ARPANet.

History 1980, another network called CSRNet – Computer Science

Research Network was linked to ARPANet. CSRNet was created to connect several independent

networks. This was the birth of internet and networking 1986, the NSF built own network National Science

Foundation (NSF)Net which was also linked to other main networks.

Powerful network in terms of speed

History Networking Technology developed, new networks all linked

to the ARPANet, Computer Science Research Network (CSRNet) and NSF Net.

Networks connected together is known as the ‘Internet’. ARPANet was finally shut down in 1989

Evolution of Client Server Concept

Evolution Evolution [growth] of networking Various reasons can be broadly categorized into following:

1. Hardware Trends2. Software Trends.3. Networking Trends.

Hardware Trends

Hardware Trends can further be divided into the following:-Power/Speed-Chips [Micro Processor]-Memory-Storage Devices

-Power/ Speed

-Chips

Chips used were 386, 486 [in MHz]. Now a days chips are available in GHz such as 1.0,2.0,

1.2,1.4,1.7,2.0, Xeon etc..

-Chips AMD’s powerful chips Athlon, Pthlon,

Sympthon etc., Processors are categorized:-

P1 -> 33Mhz ---166 Mhz. P2 ->200Mhz ---450Mhz. P3 ->500Mhz ---1.4Ghz. P4 ->1.7Ghz --- 2.0,2.1,2.4,Xeon, AMD’s

[Athlon, Pathlon]. i3, i5, i7 -> 1.7Ghz --- 3.3Ghz

-Memory

MemoryHard Disk Drive(H.D.D)

RAM for different Processors Extended

Data Output (EDO)

Static Dynamic (SD)

Dual Data Rate(DDR)

DDR3

Storage Devices Storage devices categorized into two main types:

1. Fixed Storage Devices.-H.D.D-Floppy Disk Drive-Compact disk (C.D) Drive-Digital Versatile Disk (DVD) Drive

2. Removable Storage Devices-Pen Drive-Universal Serial Bus (USB) Hard Disk

Storage Unit 4 Bits = 1 nibble 8 Bit =1 byte 1024 byte = 1KB [ Kilo byte ] 1024 KB = 1MB [ Mega Byte ] 1024 MB = 1GB [Giga Byte ] 1024 GB = 1TB [ Tera Byte] 1024 TB = 1 PB [ Pera Byte ] 1024 PB = 1 Exabyte 1024 EB = 1Zettabyte 1024 ZB = 1 Yottabyte 1024 YB = 1 Brontobyte 1024 BB = 1 Geopbyte

Software Trends

1. Graphical User Interface (GUI) Concept.2. RDBMS.3. Multi Threading Processing.

1. GUI concept GUI is Graphical User Interface. WYSWYG [What You See is What You Get].

2. RDBMS RDMBS is Relational DataBase Management System. Manage & Maintains Large DataBase. E.g. Oracle, FoxPro, SQL, MS Access. Data is stored in Tabular format. Development in C/S or networking, it is possible for various

users to access the same data at a time.

2.RDBMS

3. Multi-Thread Processing A thread is the smallest unit of process or an execution Multithreaded S/w such as Microsoft LAN manager

Network Operating S/w MS 2003 Server…etc. Support multiple threads of execution the printer, one the

keyboard I/O and another executing application code. Multithreading support allows the S/w to make more

efficient use of the H/w.

Networking Trends

Connects two or more computers for data or device sharing is known as networking.

Network is an Inter Process Communication (IPC) system in which data or message transferred b/w process and threads

Network Architecture has rules and protocols for how transfer occurs within the architecture

Networking Trends Different H/w and S/w can communicate as long as they

use the same protocols and data formats. The earliest micro LAN’s were easy to install. Provides Security and Authentication of Data Access. Categories are LAN, WAN, MAN or Virtual Private Network

(VPN)

Advantages of CST computing/ need & motivation for C/S Approach

Advantages

Networking plays a very important role. It is life line of today’s modern offices. LAN to intranet to internet.

Advantages Connectivity. Sharing Devices. Flexibility and Scalability. Centralized Control. Faster Delivery of Systems. Resource Utilization. Reduction in Network Traffic.

Advantages -Connectivity Connectivity is to connect other computers or resources. Provides the interactivity share our data or information

among multiple computers. We can also share our files on the network.

Advantages -Connectivity

‘File Sharing’ ‘Resource Sharing’ ‘Remote Accessing’.

Advantages -Connectivity

Accessing a Remote Computer through Network All these facilities are provided by the ‘Network

OS’ or the ‘Server OS’.

Advantages -Sharing Devices In CST we share various devices Sharing of resources is done through networking

Advantages -Flexibility and Scalability Segmenting the application task, an organization can

easily add a new technologies. Enhance existing technologies without interruption Add a new computer or node on a network also removed.

Advantages -Flexibility and Scalability

Add or remove Computers Data access through networking is easy

Advantages -Centralized Control

Centralized facility is the one in which data is transmitted through channel.

In past centralized facility was difficult to implement and maintain.

Client Server Technology (CST) allows facilities to combine Centralized and Decentralized Architectures.

Advantages -Centralized Control Decentralized portion of the system consists of

the processing done on the client and is the responsibility of the business and user.

Centralized portion of the system consists of the processing performed on the server and is the responsibility of Internet Securities professional as are the link to the server.

Advantages -Centralized Control Server maintains an Intelligent Database with rules and

security E.g.: Backup and Recovery procedures are centralized

Advantages -Faster Delivery of Systems

Workstation environment, powerful multitasking CPU availability, single user database and integrated testing tools.

All combine to provide the developer with considerable productivity improvements in a lower cost environment.

Server application functionality, database, and network services is transparent and almost automatic.

Network components & communication channel or media are helpful to perform faster delivery on networks.

Advantages -Reduction in Network Traffic

Excessive network traffic is one of the most common causes of poor system performance

Designers take special care to create to a avoid such situation

Reduction in Network Traffic

In client server model, it is possible to reduce the network traffic and

Provide frequent transmission of data between computers through a routers and fiber optic cable.

Client Server Environments

The Environments

Client Server is a network architecture. Components: The Client and The Server. Client runs an application using Graphical

Interface (G.I) Through this application can request the Server.

The Environments Server accepts the request and responds. Servers are classified as Web Servers, File Servers,

Terminal Servers, Mail Servers etc. Servers may have different size, OS or different purpose Basic architecture remain same

The Environments

Example of CS Technology is the internet Internet are stored on a Server machine User requests for the application to the Server Server searches

Characterization of Client/Server Computing

COMPONENTS OF CLIENT SERVER TECHNOLOGY / COMPUTING

Components

There are mainly three components.1. The Client2. The Server3. The Network

The Client Client is the desktop machine Micro or Workstation computer Network s/w sends the request to the server Accepts result form Server and passes result back to Client Client may perform some application logics

The Server

Server machine is designed for server functionality

Comparison to desktop machine Increased Memory capabilities Increased Storage capabilities

The Server

Increased processing power [ through multi processor technology].

Improved Reliability with built in reliability features such as:-Uninterruptible Power Supply-Fault Tolerance-Disk Mirroring

The Server

Evaluating server h/w:-1. Reliability2. Availability3. Flexibility

1. Reliability

Server Machine is considered as brain of networking

Directly or Indirectly controls whole network Responsible for speed and performance of

network Server machine has to be very reliable

1. Reliability

The reliability is checked by the fact that how often does it fail?

What is the mean time between failures? Does it perform automated regular data

backups? Does it has any strategy to deal with power

cuts? All these questions and many important

features of server make it a reliable machine.

2. Availability

Availability refers? Systems have self healing routines Fault tolerant alarms Specific configuration rebooted from a remote

site

Flexibility & Scalability

The application tasks, an organization can easily migrate to new technologies or enhance existing technologies with or no interruption

Application does not have to be redesigned to use a new interface s/w or be moved to new platform

We can always add a new computer or remove a node from the network

Data access through networking is also very easy through a GUI

3. The Network

Network connecting devices Managed and maintained by network Managed I/O processes

2. Distributed Working

Distributed computing is a method of computer processing

The Role of ClientUNIT II

The Client

Request to Server Network Operating System(NOS) Software who

helps in making the request and forwarding the request to the server

NOS software translates or adds the specifics required

IPC (Inter Process Communication).

The Client

Processes might be on the same computer Service provided by the NOS is redirection. Service intercepts client workstation Operating

System(OS) calls redirects them to the Server OS

The Client

Request for files, printers, serial devices, application programs

Redirected to the correct server location. Possible for some services to provided by the

client workstation.

The Client

Local disk drivers may be labelled A: or C: and the remote drives by label Z:, D: or anything else.

How does redirection works ? Requests for drive A: or C: is passed through to

the local file system by the redirection software.

The Client

Requests for other drives are passed to the server operating system.

Printers are accessed through virtual serial ports

NOS requester software constructs the Remote Procedure Call.

Application programming interface (API) calls to the NOS server.

The Client

NOS server then processes the request as it is were executed locally and response back to the application.

Novell commercialized this redirector concept for the INTEL and MS DOS platforms and it has been then adopted by all NOS.

Dynamic Data Exchange (DDE) Provides automatic information exchange It provides the linking Windows alternatives to DDE DDEML stands for Dynamic Data Exchange Management

Library Provides better interface then DDE

DDE

Mediator b/w called and calling app Calls for services are made to DDEML Passes data b/w application from different

vendors Example- Chart from excel can be linked to a

database to provide the latest data whenever the chart is referenced.

Dynamic Link Library(DLL)

File containing executable routines that can be loaded on demand by an application.

Providing standard services for many different calling applications

DLL are loaded into RAM only when needed by the calling application

DLL are files that have the extension .dll

Object Linking & Embedding

Technique or Concept which you can link or embed the object with one another

Allows user to build compound document Document is treated as a Collection of objects

rather than file Double clicking on an object starts up the

original application software and allows the user to modify the object.


Create and edit documents by using different applications

For example you can embed bitmap images, sound clips, spread sheet files and other objects in Microsoft Word documents.

Basically this feature provides us with ‘Linking’ and ‘Embedding’


Linking:- A link is added in a document Link points to the source data stored

somewhere Linked objects are stored in the document as a

path to the original linked data Changes in the data will be reflected in the

original data also.


Embedding:- Embedding adds one document directly into

other document Embedded objects are stored with the

document that contains them Change in the data in embedded file is not

reflected in the original data

CORBA

‘CORBA’ stands for Common Object Request Broker Architecture

Component architecture developed by the Object Management Group and its member companies.

Technology for creating, distributing and managing component programming

CORBA

Designed to provide interoperability b/w applications in heterogeneous distributed environments.

CORBA is not supported by Microsoft Instead has developed its own distributed

object management architecture The architecture developed by MS is called

COM(Component Object Mode) or DCOM(Distributed COM)

HOW CORBA works?

Requests service through an Object Request Broker (ORB)

ORB allows components of distributed applications

Applications communicate without knowing where the application is located in network

HOW CORBA works?

ORB’s are in fact the middleware s/w that enables client and server programs to establish session with each other.

Independent of their location in the network or their programming interface

Client issues a call which is intercepted by the ORB

HOW CORBA works?

ORB takes call and is responsible for locating a server machine that is able to process the request

Once it has located the server, it invokes the object’s methods and passes any parameters submitted by the client

The requests are then processed and the result is sent back to the client

HOW CORBA works?

ORB’s communicate among themselves using GIOP(General Inter ORB Protocol)

They also Communicate through the IIOP(Internet Inter ORB Protocol).

So ORB’s can fulfill the request of any client

CORBA vs OLE

CORBA is specification of Object Management Group(OMG)

OLE (Object Linking Embedding) focuses on data sharing b/w applications on a single desktop

CORBA addresses cross platform data transfer and moving object over networks

CORBA vs OLE

CORBA support enables windows and UNIX clients to share objects.

A word processor operating on Windows platform can include graphics generated from UNIX workstation.

RPC(Remote Procedure Cell)

Message passing programming technology developed by Sun Microsystems and extended by the Open Software Foundation (OSF)

Applications to execute procedures and interact with services on a remote computer on network

CST on MS windows server 2000 and window NT platforms is enabled using RPC’s

How it works?

RPC is to pass messages b/w components of a distributed application that are located on different computers on a network.

Local Procedure Calls(LPC’s) provide a mechanism for enabling different parts of an application located on a single computer to communicate with each other.

How it works?

RPC’s provide a mechanism through which computers on different networks can communicate with each other

In fact RPC’s use a wide variety of IPC mechanisms such as NetBIOS (Network Basic Input Output System), windows sockets, mail slots to establish connections between the RPC client and the RPC server

How it works?

The Remote Procedure Call service (RPC service) is a component of the Windows NT executive running in kernel mode

It is responsible for message passing b/w the client and the server components of a distributed application

Message is passed b/w client server application such as MS outlook express and MS exchange server

How it works?

On a windows NT based network the server first registers itself with the RPC Locator service

The client part of the application which is on the local computer can then query the RPC locator service to determine the location of the required server part.

The RPC server located server is a part of the operating system located on the client machine.

How it works?

A process called the remote procedure stub then packages the clients function call into a suitable RPC message and sends it to the remote computer using RPC run time process

At the remote machine a process called the application stub receives the RPC message

How it works?

It unpackaged the message into a function call and executes it, returning any resulting values to the client part in a similar fashion.

From the view point of the client part of the application, the server part appears to be on the same computer.

CST Application

CST Applications

Applications that run on a network, technically different from application running on a local machine.

Applications which are specially designed to run on network are known as ‘Distributed applications’.

The technology of creating and running an application in parts is also called ‘application partitioning’.

CST Applications

A distributed application consists of a server portion where most of the processing and storage is performed.

This server portion is always executed and stored on the server

This is also known as the ‘Back-End’.

CST Applications

The part of the application that runs on the client and which provides the interface to the client is known as the ‘front-end’

The front-end through its interface provides many functionalities to the client.

The client can performs many important tasks using this interface.

CST Applications

In the CST model, an application is split into a front- end client component and a back-end server component.

The front-end part of the application runs on a workstation and receives data that is input by the user.

The client’s front-end prepares the data for the server by preprocessing it in some fashion.

CST Applications

This processed information is then sent to the server.

The data is sent to the server in form of some request.

The back-end server component receives the client’s request and processes it and returns information to the client.

The client receives the information and presents it to the user

CST Applications

A good example of CST application is a web application that is designed for Internet Information Services(IIS).

Such applications are prepared by using ASP(Active server pages) programming and client side scripting.

The ASP program runs on the server and the client side scripting runs on the client.

CST Applications

Basically a CST application has three main components: The front-end application The back-end application Network operating system

The Front-End & Back-End

In its general meaning, the term ‘Front-End’ refers to the initial and the end stages of process flow.

These terms acquire more special meanings in particular areas

The general idea is that the front-end is responsible for collecting input from user.


The input can be in a variety of formats but is processed in such a way that it conforms to a specification that the back-end can use.

The connection of the front-end to the back-end is through the interface

In a s/w design, the front-end is the part of s/w system that interacts directly with the user.

Front-End

Back-End


The back-end is the part which contains components that processes the output for the front- end.

The separation of the ‘front-end’ and ‘back-end’ is a kind of abstraction.

Abstraction helps to keep different parts of the system separated

There are many example of front-end and the back-end which are used in computer field.


Front-end is the part or the interface that helps a user to interact with the machine.

For example:- Windows explorer can by defined as the front-end to the computer file system.

Similarly the GUI interface on the machines can be defined as the front-end of the machine.

Most of the s/w packages have a front-end with which user interacts and operates the s/w.


In complies the front-end translates a computer programming source language into an intermediate representation

And the back-end works with the internal representation to produce code in a computer language

The back-end usually produces machine language code that runs faster


Similarly when we create s/w using dot net, dot net works as the front-end.

Whereas the database where the data is stored Example:- SQL or Oracle is called the back-end.

Network Software

In order to define ‘Network s/w’ one must define the individual terms ‘Network’ and ‘s/w’

A network is made up of two or more computers that are linked together.

Networks can be used for a variety of purposes Generally networks are used to send

information from one computer to another computer.

Network Software

They are also used to play games or talk to a friend or to combine computing power.

S/w can be defined as a program or a set of programs written to perform specific tasks.

So, using the definitions of network and software we can define network s/w as follows:

Network Software

Network s/w makes it possible for computers to communicate or connect to one another.

It can also be defined as the s/w which helps to send information from one computer to another.

The network s/w contains information about how data is to be sent in packets to another computer.

Network Software

Packet information includes the ‘header’ and the ‘trailer’

The header and the trailer contains information for the computer to which the information is being sent.

This information includes address of the computer to which the packet is sent, and how the information is coded etc.

Network Software

Information is transferred b/w computers as either electrical signals in wires, as light signal in fiber optical cable or as electromagnetic waves.

Thus network s/w is the s/w which helps computers in a network to communicate with each other.

They are also responsible for sending/exchanging information b/w two computers

Some network s/w are Windows Server2003, Linux, Window Server 2000, Novell Network etc.

Role of serverUNIT III

On the basis of Usage

1. FILE SERVER2. COMPUTER SERVER3. DATA SERVER4. COMMUNICATION SERVER5. APPLICATION SERVER

1. Manages workgroups applications & Data Files Shared by the group and among the groups File Servers are I/O oriented

1. Large amount of data Storage and data transfer Space for storage is allocated and free space is managed

by the file server Whenever data from a file is requested, a file server

transmits all records of a file and the entire index to the client

1.

Requires many slots for network connection It also needs a large storage capacity and fast

hard disk sub-system. The main work of file server is to manage,

maintain and serve the file whenever a file is requested.

2. Compute Server

Compute Server is used in a 3 Tier Architecture Processing Server CS passes client requests to a data server Forwards the result Processing on the client request. Processing authenticity for security.

3. The Data Server

Data storage and management. Conjunction of one or more computer servers

3. The Data Server

Processing is done by rule based procedures Data validation, requires data management

function. Multiple searches of data and frequent updates

of massive tables.

3. The Data Server

Task require fast processors Large amount of memory and substantial hard

disk capacity. Servers send relatively small amount of data

across the network.

4. The Communication Server Communication Servers provide gateways to LAN’s,

Network System requirements with perhaps the greatest demands

being those for multiple slots and fast processors. Powerful h/w to translate networking protocols.

5. Application Server

Application server is a machine that Server as a host

Applications are downsized from a host, one option is to install the application on a smaller machine that runs the same s/w & to hook all the users to the new box

Process Requires no modifications to the based app s/w

Host is server to GUI based clients

On the basics of SizeMICRO SERVERSUPER SERVER

Micro Server :- Performs all the functions which a Server needs Micro Servers used the Intel 486 Chips to run at 33Mhz or

higher with 16 MB RAM.

Micro Server

Multiprocessing provided by certain O.S do not provide multiprocessing

Example:- Novell’s Netware does not provide multi tasking

Micro Servers use Intel 3.06GHz or Xeon or higher processing speed chips with 1 to 4 GB RAM

OS support Symmetric multiprocessing

Micro Server

Latest Servers use Dual Core Technology having 64 Bit processing capabilities

Tremendous processing and executing powers

2. Super Server

Super Server is specifically designed for the CST

Provides certain hardware features Multiple processors, large amounts of memory High speed disk arrays Specialized applications are used

Super Server Higher configuration h/w & s/w Advantage over a Micro Server

Increased Processing Power : multiple processors Increased I/O capabilities : Increased disk capacity : Improved Memory Management : Improved reliability :

Super Server Improved maintainability : Eg : Param (Pune, India)

ANURAG (India) CLAY 1, CLAY 2 and CLAY 3, CRAY.

Features of Server Server plays a very important role in the network Speed and the Performance of a network Server machine is a powerful machine The general features possessed by a server are as follows :

Multi Processing Multi Threading

Features Disk Arrays

Disk Mirroring Disk Duplexing Parity Checking RAID Components

1. Multi Processing Multiple processors to increase processing speed Workload is shared by the processors Multiple processing can be further classified

1. Symmetric Multiprocessing Dynamically assigned to any processor Processing speed and resources are maximized Capability supported by the Network Operating System(NOS) or

Server Operating System (SOS) Application s/w should also support multiprocessing

SCHEDULER

Network Services

File Systems

DBMS Engine

Print

Disk I/O

Processor Processo

r

Processor

Processor

Symmetric Multiprocessing

1. Multi Processing

2. Functional Multi Processing Assigns a set of tasks to a processor Multi processing also supports multi threading Concurrent execution of multiple tasks

Network Services

File System Print Disk

I/O

Network Services Processo

r

File Systems Processor

Print Process

or

Disk I/O Process

or

Functional Multiprocessing

2. Multi Threading

Thread is smallest unit of execution System can schedule it to run A path of execution through a process Thread consists of stack, an instruction pointer,

a priority, the CPU state and an entry in the system’s scheduler list.

Thread may be blocked, scheduled to execute or running.

2. Multi Threading

Thread communicate by sending messages to each other and they compete for ownership of various semaphores

The allocation of computing resources between the individual threads

Thread asks the system for an instruction to carry out.

2. Multi Threading

If no instruction is ready, the thread is suspended until it has something to do

If the instruction is ready, the thread performs the task and makes another request to the system for work

3. Disk Array

Fault tolerant disk arrays, Redundant Array of Inexpensive Disks(RAID)

Such Disks are standard on super servers Disk Array’s usually include a file server and

software that controls access to the individual drives.

Data File

RAID Redundant Array of Inexpensive Disks

RAID

Multiple drivers are treated as a single logical drive by the server operating system

Transparently recover from the failure The data is actually broken into chunks and

simultaneously written to multiple disks

RAID

If a disk fails, the data can be reconstructed by reviewing the places of data

RAID currently has five levels of data protection and error correction

1. Disk Mirroring

Disk Mirroring is the process of creating a mirror duplicate of a disk

Such facilities are usually provided by the SOS In this system two disks are attached to the

same disk controller

2. Disk Duplexing

Creating duplicate disk. Individual controllers are provided for each disk One of the disk is duplicated

3. Parity Checking

An extra bit is added to ensure that the information is transmitted accurately

The extra added bit is called the ‘Parity Bit’

4. Redundant Components

Redundant Server Components such as disk driver. Power supplier an automatic supplier and automatic recovery features are option on servers and standard on super servers.

Some super servers offer mirrored processors and include remote alarms that immediately warn of network trouble.

Network Operating SystemNOVELL NETWARELAN MANAGER

Network Operating System

Server Operating System is NOS Operating system which is aware of a network Additional features than a normal operating

system


These features include: File and Printer Sharing Data Security and Authentication Distributed Applications Messaging Centralized Administration


Its main task is to receive and respond to user requests for services

A NOS manages the services of a server Various Network management tools Run many other software Generally an operating system manages the

resources of the server


Software to communicate with other computer via a network

Manages multiple requests concurrently Self contained operating system


For example:- Windows NT, UNIX Remote drives on the server can be accessed The server to handle requests from the client to

share file and applications as well as network devices

Network Operating System LAN’s which can either be peer to peer networks or CST

based. Example:- NOS include Windows NT, Novell Netware and

Banyan VINES. Cisco’s Internet Work Operating System (IOS) can be used

as OS on router


Peer-to-peer network, the NOS allows each station to be Client & Server

Non peer to peer network, dedicated servers are used

File and print services a network OS include directory services.

Messaging service as well as network management and multi protocol routing capabilities.

Network Operating System NOS can be used for a variety of purposes.

The basic functions of a NOS are: Authenticate user access Share files and printers and exchange messages.


Centralizing administration of multiple computers from a single management console.

Distributed applications that share processing on multiple computers.


Some of the popular NOS are: Microsoft Windows 2000/2003/2008/2012. Novell NetWare Various flavours of UNIX LINUX Mac OS etc..

1. Novell NetWare

Novell that support DOS, Windows, OS/2 and Macintosh clients

Network Operating System Supports file and printer sharing, email, remote

access, inter LAN communication via a bridge or a gateway

1. Novell NetWare

Controlling system resources and their uses. Different versions

Version depends on type of services

Novell NetWare

The different versions of Novell Netware are : Novell NetWare Lite Novell NetWare 2.2 Novell NetWare 3.11 Novell NetWare 4.0

With each new version of Novell NetWare some new additional features were added to it.

Novell NetWare

Some of the features include: Increased number of clients can be connected

the server. Better memory management. Support for latest processor. Support for increased RAM. Support for Multiple protocols.

Novell NetWare

Better security options (Example:- Disk Mirroring, disk duplexing or redundant components)

NetWare is used by organization, large and small

Provides common services

LAN Manager

Developed by IBM LAN manager is NOS for networking Different network OS according to

characteristics Requires that the server run OS/2 Clients use Macintosh or any OS Works across multiple protocol

LAN Manager

Basic Features provided are: Concept of Domain Name System. Support for Multiprocessing. Remote access service Latest features a Server needs

Server Operating System

LINUXOS/2

Linux

Introduction Supports a large number of hardware Provides multiuser multitasking OSE(Operating

System Environment) Freely used on WS(Web Server), DNS(Domain

Name System), File Server(FS) etc… Server side Application:

Apache Web Server Samba Server

Samba enable a Linux Server to provide file and print services to other platforms such as Windows and Apple Macintosh.

OS/2

OS/2 server platform, intel’s product Provided by IBM in SAA(System Application

Architecture) model Multitasking services Network Operating System directly supported

with OS/2 are LAN Manager and LAN Server. Combination of Novell with OS/2 DataBase And

Applications Server.

System Application Architecture

SAA is IBM’s distributed environment SAA define standards for CUA(Common User

Access), CPI(Common Programming Interfaces), Common Communication Link.

SAA framework is AD/Cycle AD/Cycle designed to use third party tools

client server ArchitectureUNIT IV

Concept & Components of C/S

C/S architecture is based on framework Consists of many PC’s, workstations & small

mainframe machines Connected with communication media or

channel.

Tiered Architecture Generally there are two types of nodes in a network. One is Client and another is Server. Two Tiered Architecture “the Client and the Server”. Directly sends a response to the CS. Direct communication between CS.

Main types of DBMS architecture:1. Two tier Architecture2. Three tier Architecture

Two Tiered Architecture In a two tiered architecture there is no third party

[machine ] involved.

The server

2 Tiered Architecture

Client

Advantages of 2 Tier Architecture

Easy to update data Easy to upgrade and maintain such networks

Disadvantages of 2 tier Architecture

Traffic jams in networking Large number of clients sends requests and this

causes troubles for the server More Clients more trouble Server goes down and the Clients requests

cannot be fulfilled

Three Tiered Architecture

Networks consists of three different kinds of nodes: Client : which requests data Server : which processes data Database Server : which stores data.

Such an architecture is called ‘ Three Tiered Architecture’.

Client

The Google Server

The Facebook Server

3 Tiered Architecture


3-tier architecture one Server free to only processing.

Server stores all the data only and does no need to do any processing.

Load/Burden is reduced on the Server. Servers perform much better


Better security control on data. A Hacker has to pass through the processing

server to reach to the database

Disadvantages of 3 Tier Architecture

Load on the network Difficult to run or test a software

Communication Between C/S

Client requests to the server for data or information

Server is the machine which serves the data or information.

ORB are the middleware that enable Client & Server programs to establish session with each other

Client & Server can communicate, independent of their location on the network or programming interface

Process of Client invoking or call to an Application Programming Interface(API)

Client issues the call, which is intercepted by the ORB ORB takes call & is responsible for locating a server object

that is able to implement the request ORB communicate among themselves using the General

Inter-ORB Protocol (GIOP) or Internet Inter-ORB Protocol(IIOP)

Any ORB can fulfil any Client request on the network

Use of API Application Programming Interface let C and Assembly

language interact with services and programming tools Window OS provides API to access standard operating

system and networking services and functions Window OS provide predefined sets of API for various

purposes:- (Telephony)TAPI for accessing voice, data of fax (Messaging)MAPI for messaging functions

API call to the computer browser service

Middleware technology in CSC

Three tier architecture Intermediate layer between the client and

database server

Open System Interconnection(OSI)

Intro: OSI was developed by ISO(International

Organization for Standardization) Model for universally accepted networking

protocols Model describes how information moves Conceptual model composed of 7 layers

Upper Layer of software layer

Heart of OSI

Lower Layer of hardware layer

7654321

OSI Reference Model: 7 Layers

OSI Model

1. Physical Layer First layer of OSI model ‘Nut & Bolts’ layer Physical interface b/w devices Physical and electrical connection Transmission media Different protocols

2. Data Link Layer

2nd layer of the OSI model Converts frames of data Responsible:

Framing, Flow control, Error free Communication Bridges and NIC work on this layer Ensures that the data is transferred reliably Responsible for addressing, Frame sequencing,

error detection and recovery

Data Link Layer

Layer deals with getting data packets on and off the wire

Error Detection, Correction and Retransmission Layer is divided into two layers

LLC – Logical Link Control MAC – Media Access Control

Frame

PacketData Trailer

Data Header

CRC(Cyclic Redundancy Check)

Source MAC AddressDestination MAC Address

A cyclic redundancy check (CRC) is an error-detecting code commonly used in digital networks and storage devices to detect accidental changes to raw data.

http://en.wikipedia.org/wiki/Error_detection_and_correction

http://en.wikipedia.org/wiki/Telecommunications_network

3. Network Layer

Addressing and routing of packets Establishing and releasing connections Transferring data, Generating and confirming

receipts and resetting connections Packets sent from one device to another Routing and flow control are formed here

Packets

SegmentNetwork Header

Source IP AddressDestination IP Address

4. Transport Layer The Heart of the OSI model Responsible for providing reliable transport services to

Upper Layer Flow control Multiplexing for combining data from several sources Layer uses TCP/IP protocol Port is a Logical Communication Channel

Segment

DataTransport Header

Source Port NoDestination Port NoProtocol NoSequence No

It provides data delivery mechanism b/w the application in the network

Hello!

How

ARE You ?

sequencing

Hello!1/5

How

2/5

ARE

3/5You4/5

?5/5

5. Session Layer

Responsible for: Establishing and Terminating a session in a

network Synchronizing data exchange b/w 2 computers NetBIOS protocol works at this layer Sessions ID’s

Examples: RPC – Remote Procedural Call SQL – Structured Query Language ASP – AppleTalk Session Protocol

6. Presentation Layer

Presentation layer is responsible for1 Data Translation2 Data Compression3 Data Encryption.

Interpretation of graphics commands

E.g.: ASCII, MIDI, WAV, MP3 etc.

6.1. Data Translation Application layer will need to convert data Receiving format understood and accepted OSI model to ensure smooth file transfer Data formats include postscript, American Standard Code

for Information Interchange (ASCII), or BINARY such as Extended Binary Coded Decimal Interchange Code (EBCDIC)

6.2. Data Compress

The goal of data compression is to represent an information source (a data file, an image) as accurately as possible using the fewest number of bits

For example, 25.888888888 This string can be compressed as: 25.[9]8

Interpreted as, "twenty five point 9 eights", the original string is perfectly recreated, just written in a smaller form

6.3. Data Encryption.

Process of transforming information (plaintext) Using an algorithm (called cipher) to make it

unreadable to anyone except those possessing special knowledge

Usually referred to as a key. Result of the process is encrypted information

(referred to as cipher text).

7. Application layer

Window b/w user and other networking services

Runs the s/w with which the user interacts

FTP and HTTP protocols are used Layer acts as an interface b/w

user and network

7. Application layer Protocols HTTP – Hyper Text Transfer Protocol FTP – File Transfer Protocol POP – Post Office Protocol SMTP – Simple Mail Transfer Protocol SSL – Secure Socket Layer Telnet – for remote computer access

IPC (Inter Process Communication)

Allows one process to communicate with another process

Processes run on same computer or on different computers which are connected through a network

IPC techniques are divided into methods Message passing, Synchronization, shared

memory and Remote Procedure Calls(RPC)

Client Server Computing written by Munesh Trivedi

Or Mamta Rani The Essential Client/Server survival Guide

written by Robert Orfali , Dan Harkey Or Jeri Edwards

Unit V

C/s system development

Network Management

Network means connecting two or more computers in such a way that they are able to share data & h/w

Networks can by very small or very large Every type of network faces problems regularly Problems need to be solved regularly for easy &

good performance of the network

Network Management

Network can face the following problems:-1. No connection2. Wrong or no user accounts3. Faulty or loose wires4. Domain name problems5. Server down6. H/w problems (switch, router)

Network Management

7. No services available8. Wrong or invalid permissions9. Server OS problems

Network has to be managed regularly “Network Administrator”

Five key OSI management areas Fault management Performance management Inventory management Accounting management Configuration management Security management

Remote System Administrator

Able to create very large network C/S machine very far form each other Access files or folders Install or uninstall any s/w, format, restart Save time & money Facility provided by the OS

Remote System Administrator

Remote administrator can also be very dangerous Unauthorized user can easily Access Hacking Difficult to catch such user

LAN Management

LAN Limited area in a campus Regular problems Management is also compulsory Same Network management

The responsibility of network administrator or LAN administrator that the entire network will not be crashed or failed.

The data or information will never be lost on any cost

LAN network management there are certain issues or services Network Maintenance Network Integration Capacity Planning Equipment Maintenance Security Administration Network Cabling & Installation Network Application & Administration Server & PC Data Backup

1. Network Maintenance

The computer are connected with each other The structure & layers what type of connections

are used for better network We can use routers at some places, hubs,

switches Facilities of disk mirroring, disk duplexing There is less possibility of network failures We can maintain the network & make it work

efficiently & effectively

2. Network Integration

Network Integrity mean that all the systems should work & function Homogenously

System should have a contact with the Server

Developing Application On RDBMS

RDBMS S/w used to store large amount of data Processes data & provide information to user Technical users use SQL & RDBMS GUI

Developing Application On RDBMS

Designed in s/w like VB6 or VB.net Screen fully graphical, friendly & easy to use Screens acts as “FRONT-END” RDBMS acts as “BACK-END” Used in Banks, Railways, govt. offices etc…

GUI Design Concepts GUI Gives controls to work in GUI Help to work easily & fast Controls include textbox, radio button etc… Important role in designing graphical screens

Client server technology main

Technology

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