MCSE

This situation occurs when the minimum hardware requirements of OS is not sufficient then blue screen appears.

It is the technical term for data transmission in the direction from the subscriber to the network. Or rather, back to the provider or Internet provider. It is called as back channel. The opposite transmission direction, the 'transmission channel', is called the 'uplink' in technical jargon.

A panel of network ports contained together, usually within a telecommunications closet that connects incoming and outgoing lines of a LAN or other communication, electronic or electrical system. In a LAN, the patch panel connects the network's computers to each other and to the outside lines that enable the LAN to connect to the Internet or another WAN. Connections are made with patch cords. The patch panel allows circuits to be arranged and rearranged by plugging and unplugging the patch cords.

User interface

# Business Logic and

# Shared data

They were originally introduced to run classes of applications that could service hundreds and sometimes thousands of clients. TP Monitors provide an OS - on top of existing OS - that connects in real time these thousands of humans with a pool of shared server processes.

The client

# The server and

# Middleware

The client side building block runs the client side of the application.The server side building block runs the server side of the application.

The middleware building block runs on both the client and server sides of an application. It is broken into three categories:-

# Transport stack

# Network OS

# Service-specific middleware

SQL is a powerful set-oriented language, which was developed by IBM research for the databases that adhere to the relational model. It consists of a short list of powerful, yet highly flexible, commands that can be used to manipulate information collected in tables. Through SQL, we can manipulate and control sets of records at a time.

# Service

# Shared resources

# Asymmetrical protocols

# Transparency of location

# Mix-and-match

# Message based exchanges

# Encapsulation of services

# Scalability

# Integrity

Client/Server computing is the ultimate "Open platform". It gives the freedom to mix-and-match components of almost any level. Clients and servers are loosely coupled systems that interact through a message-passing mechanism.

RPC hides the intricacies of the network by using the ordinary procedure call mechanism familiar to every programmer. A client process calls a function on a remote server and suspends itself until it gets back the results. Parameters are passed like in any ordinary procedure. The RPC, like an ordinary procedure, is synchronous. The process that issues the call waits until it gets the results.

Under the covers, the RPC run-time software collects values for the parameters, forms a message, and sends it to the remote server. The server receives the request, unpacks the parameters, calls the procedures, and sends the reply back to the client. It is a telephone-like metaphor.

# Resource Manager

# Transaction Manager and

# Application Program

Non-GUI clients - Two types are-

1. Non-GUI clients that do not need multi-tasking(Example: Automatic Teller Machines (ATM), Cell phone)

2. Non-GUI clients that need multi-tasking(Example: ROBOTs)GUI clientsOOUI clients

MOM allows general-purpose messages to be exchanged in a Client/Server system using message queues. Applications communicate over networks by simply putting messages in the queues and getting messages from queues. It typically provides a very simple high level APIs to its services.

MOM's messaging and queuing allow clients and servers to communicate across a network without being linked by a private, dedicated, logical connection. The clients and server can run at different times. It is a post-office like metaphor.

Middleware is distributed software needed to support interaction between clients and servers. In short, the software is in the middle of the Client/Server systems. In addition, it acts as a bridge between the clients and servers. It starts with the API set on the client side that is used to invoke a service and it covers the transmission of the request over the network and the resulting response.It neither includes the software that provides the actual service - that is in the server's domain nor the user interface or the application login - that is in client's domain.

It treats all processors as equal. Any processor can do the work of any other processor. Applications are divided into threads that can run concurrently on any available processor. Any processor in the pool can run the OS kernel and execute user-written threads.

It includes the communication stacks, distributed directories, authentication services, network time, RPC, Queuing services along with the network OS extensions such as the distributed file, and print services.

It imposes hierarchy and a division of labor among processors. Only one designated processor, the master, controls (in a tightly coupled arrangement) slave processors dedicated to specific functions.

If the number of incoming clients requests exceeds the number of processes in a server class, the TP Monitor may dynamically start new ones, and this is called Load balancing.

# Database Servers

# TP Monitors

# Groupware

# Distributed Objects

# Intranets

Clients and Servers are separate logical entities that work together over a network to accomplish a task. Many systems with very different architectures that are connected together are also called Client/Server.