nayapaan

2011-04-18T21:17:00.000-07:00

कोई दीवाना कहता है कोई पागल समझता है
मगर धरती की बैचेनी को बस बादल समझता है।
मैं तुझसे दूर कैसा हूँ, तू मुझसे दूर कैसी है
ये तेरा दील समझता है या मेरा दील समझता है।
मुहब्बत एक अहसासों की पावन सी कहानी है
कभी कबीरा दीवाना था, कभी मीरा दीवानी है।
यहाँ सब लोग कहते हैं, मेरी आंखों में आँसू हैं
जो तू समझे तो मोती है , जो ना समझे तो पानी है।
समंदर पीर का अम्बर है लेकीन रो नहीं सकता
ये आंसू प्यार का मोती है इसको खो नहीं सकता
मेरी चाहत को दुल्हन तू बना लेना मगर सुनले
जो मेरा हो नहीं पाया वो तेरा हो नहीं सकता
भ्रवर कोई कुमद्दीनी पर मचल बैठा तो हंगामा
हमारे दील में कोई खवाब पल बैठा तो हंगामा
अभी तक डूब कर सुनते थे सब कीस्सा मोहब्बत का
मै कीस्से को हकीक़त में बदल बैठा तो हंगामा

जींदगी की असली उड़ान अभी बाकी है
हमारे इरादों का इम्तीहान अभी बाकी है।
अभी तो नापी है सीर्फ मुट्ठी भर ज़मीन
आगे सारा आसमान अभी बाकी है ॥...

लहरों से डर कर नौका पार नहीं होती,

MERI ANKHON MEIN

2011-02-25T00:07:00.003-08:00

Mere Bistar Pe So Raha Hai Koi
Meri Ankhon Mein Jaagta Hai Koi

In Pahado Mein Rehte Hain Humzaad
Bol Kar Dekh Bolta Hai Koi

Aaj Main Jagoonga Ki Sote Hue
Meri Palko Ko Choomta Hai Koi

Mera Shaitan Mar Gaya Shayad
Mere Seene Pe So Raha Hai Koi

Rang Ye Bhi Bahut Purana Hai
Sochta Koi, Bolta Hai Koi

Saath Pardon Mein Chup Ke Dekh Liya
Kapde Badlo To Dekhta Hai Koi

ITNI SIYAH RAAT

2011-02-25T00:07:00.001-08:00

Taaro Ki Chilmano Se Koi Jhankta Bhi Ho
Is Kaynaat Mein Koi Manzar Naya Bhi Ho

Itni Siyah Raat Mein Kisko Sadayein Doon
Aisa Chirag De Jo Kabhi Bolta Bhi Ho

Rango Ki Kya Bahar Hai Pathar Ke Baag Mein
Lekin Meri Jameen Ka Ik Hissa Hara Bhi Ho

Uske Liye To Maine Yahan Tak Duayein Ki
Meri Tarah Se Koi Use Chahta Bhi Ho

2011-01-01T02:26:00.000-08:00

Every moment is precious

to realize the value of

One year : Ask a student who has failed in his exam.

One month : Ask a mother who has given birth a

premature baby.

One week : Ask an editor of weekly periodical.

One day : Ask daily wage labour.

One hour : Ask the lovers who waiting to meet one another.

One minute : Ask the person who missed the flight / train / bus.

One second : Ask – some one who survived and

accident.

One mili second : Ask the sprinter who missed the gold medal in Olympics.

so, Tresure every moment you have !

Yesterday is History.

Tomorrow is mystery.

But Today is a gift.

So we all it “PRESENT.”

the different types of hazards

2010-12-29T01:48:00.000-08:00

There are three types of hazards.

[1] Structural hazards

[2] Data hazards

[3] Control hazards

[1] STRUCTURAL HAZARDS

When a machine is pipelined the overlapped execution of instructions requires pipelining of functional units and duplication of resources to allow all possible combinations of instructions in the pipeline. If some combinations of instructions cannot be accommodated because of resource conflicts, the machine is said to have a structural hazard. The most common instances of structural hazards a lies when some functional units is not fully pipelined Then a sequence of instructions using that not pipelined unit cannot proceed at the rate of one per clock cycle. Another common way that structural hazards appear is when some resource has not been duplicated enough to allow all combinations of instructions in the pipeline to execute.

For Example

A machine may have only one register. File write part but under certain circumstances the pipeline might want to perform two writes in a clock cycle.

[2] DATA HAZARDS

A major effect of pipelining is to change the relative timing of instructions by overlapping their execution. This introduces data and control hazards. Data hazards occur when the pipeline changes the order or read/ write accesses to operands. So, that the order differs from the order seen by sequentially executing instructions on not pipelined machine.

[3] CONTROL HAZARDS

Control hazards can cause a greater performance loss than the data hazards when a branch is executed. It may or may not change the PC to something other than its current value recall that if a branch changes the PC to its forget address, it is a taken branch, if it falls through. It is not taken branch then the PC is normally not until the end of MEM, after the completion of the address calculation and comparison.

The simplest method of dealing with branches is to stall the pipeline as soon as we detect the branch until we reach the MEM stage, which determines the new PC of course. We do not want to saw the pipeline until we know that the instruction is a branch.

What is Pipelining? Explain the principles of pipelining

2010-12-29T01:45:00.000-08:00

Pipelining is an implementation technique where by multiple instructions are overlapped in execution. Today pipeline is the key implementation technique used to make fast scopes.

PRINCIPLES OF PIPLINING

Assembly lines have been widely used in automated industrial plenty in order to increase productivity their original form is a flow line of assembly stations where items are assembled continuously from separate parts along a moving conveyor belt. Ideally all the assembly stations should have equaled processing speed otherwise the slowest station becomes the bottleneck of the entire pipe. This bottleneck problem plus the congestion caused by improper buffering may result in many idle stations waiting for new parts. The a proper sequence of subtasks becomes a crucial factor in determining the performance of the pipeline.

The precedence relation of a set of subtasks [ T1, T2, … TK] for a given task T implies that some task Tj cannot start until some earlier task Ti [Kj] finishes the inter dependencies of all substasks form the precedence graph with a line precedence relation. Task Tj cannot start until all easies subtasks {Ti, for all K=J} finish a liner pipeline can process a succession of subtasks with a inter precedence graph. The stages are pure combinational circuits performing arithmetic or logic operations over the data stream flowing through the pipe. The stages are separated high-speed interface latches separate the stages. The latches are fast registers for holding the intermediate results between the stages.

Addressing Modes

2010-12-29T01:42:00.000-08:00

(A) REGISTER MODE

The operand is the contents of a processor register the name (address) of the register is given in the instruction processor register are used as temporally storage locations. Where the data in a register are accessed using the register mode.

(B) ABSOLUTE MODE

The operand is in a memory location the address of this location is given explicitly in the instruction. The absolute mode can represent global variables in program a declaration such as integer A.B; in a high level language program will cause the complier to allocate a memory location to each of the variables A and B.

(C) IMMEDIATE MODE

The operand is given explicitly in the instruction address and data constants can be represented in assembly language using the immediate mode.

For example

The instruction move 200 immediate, replaces the value 200 in register or clearly the immediate mode is only used to specify the value of a source operand.

Using a subscript to denote the immediate mode is not appropriate in assembly languages. A common collection is to use the sharp Sign (#) in front of the value to indicate that this value is to be used as an immediate operand.

(D) INDIRECT MODE

The effective address of the opened is the contents of register or memory location whose address appears in the instruction we denote indirection by pacing the name of the register or the memory address.

the function of functional units of computer

2010-12-29T01:41:00.000-08:00

Following figure shows the functional units of a computer it consists of five main parts.

(1) INPUT UNIT

(2) OUTPUT UNIT

(3) MEMORY

(4) ARITHMETIC AND LOGIC UNIT

(5) CONTROL UNIT

The input unit accepts the coded information from the keyboard of a video terminal or from other computer over digital communication line. ALU and control unit together called as CPU or simply a processor.

(1) INPUT UNIT

Computer accepts the coded information through the input unit. It has the capability or reading the instructions and data to be processed the most commonly used input devices are keyboard of a video terminal. This is electronically connected to the processing part of a computer. The keyboard is wired such that whenever a key is pressed the corresponding letter or digit is automatically translated into its corresponding code and is directly sent either to memory the processor.

(2) OUTPUT UNIT

Output unit displays the processed result. Examples are video terminals and graphic displays. Input and output unit is usually combined under the term I/O unit for example considers the keyboard of a video terminal. This consists of keyboard for input and a cathode ray tube display for output. I/O devices do not alter the information. Content or meaning of the data some devices can be used as output only.

(3) MEMORY UNIT

Memory unit is an integral part of a computer system. Main function of a memory unit is to store the information needed by the system. Typically it stores programs and data. The system performance is largely dependent on the organization. Storage capacity and speed of operation of the memory system can be broadly classified into four groups.

I. Internal memory

II. Primary memory

III. Secondary memory

IV. Cache memory

(4) ARITHMETIC AND LOGIC UNIT

The arithmetic and logic unit is the ‘CORE’ of any processor its unit that performs the calculations. A typical ALU will have two inputs ports and a result port. It will also have a control input telling it which operation to perform and additional outputs for condition codes.

Arithmetic unit

The arithmetic unit performs typical arithmetic operations such as addition subtraction. Increment and decrement usually by unity. This unit includes the necessary hardware required for operation on signed and unsigned integers. Floating point numbers and BCD numbers etc. this multiplayer selects either Y OR X depending on the selection line so which is also the carry-in input of the addle.

If so = 0 output is f = x + y

If so = 1 output is f = x + y + 1 were y + 1 is 5

Hence the output is f = x – y

(Compliment of Y)

Consider a simple logic unit which can perform two logic operation AND or EX- OR here also multiplexer selects either or these operations depending on the state of so.

If so = o output G = X AND Y

If so = 1 output G = X CD Y

Some additional hardware can be added to the above basic logic unit perform the Boolean operations.

For example

X = X + 1

Y + Y + Y * Y = X OR Y

Arithmetic and logic units are combined together to form ca complete ALU. Outputs F and G are multiplexed with a nibble multiplexer to get a single output depending on the selection lines of the nibble multiplexer the selection line is sometime known as mode selection line since it selects the desired mode either arithmetic or logic.

(5) CONTROL UNIT

The purpose of control unit is to control the system operations by routing the selected data items to the selected processing hardware at the original time control unit acts as nerve centre for the other units. This unit decodes and translators each instruction and generates the necessary enable signals for ALU and other units. Control unit has two responsibilities. I.e. Instructions interpretation and instruction sequencing

The operation of the computer can be summarized as below.

v The computer accepts in formation through the input unit and transfers it to the memory.

v Information stored in the memory is fetched into arithmetic and logic unit to perform the desired operations.

v Processed information is transferred to the output unit.

v All activities inside the machine are controlled by a control unit.

Why .NET

2010-12-29T01:36:00.000-08:00

Despite its substantial popularity, com suffers from a numbers of limitations.

.Com itself offered for binary code reuse; it did not offer a model for source code reuse. An implication of this is that, although com offered interfaced-based inheritance. It did not support code-based inheritance.

Although .com offered the promise of a language independent architecture, reality often fulfill short of the premise. The root of the problem was the fact that seamless interoperability with com presupposed that each language was able to create and manipulate common automation compatible data types. This however was not the case. As a result although com made some real advances in the area of language independence it also had some real weaker ness.

.Com was extremely complex and for the most part only c++ programmers were able to work with com directly for VB programmers the visual basic failed to give the developer full control over com when it was needed and many visual basic programmers often locked sufficient even of those features that they were able to control.

In addition .com did not offer an integrated class library comparable to the .net FCL. Instead the developers of each application or operating system service were free to implement whatever object model made sense to extend their application. As a result, there are major gaps in the functionality made available through .com automation and there is not a good deal of consistency across object models.

The .NET platform and the .NET framework class library were developed in an effort to address these weaknesses of.com.

polymorphism

2010-12-29T01:33:00.001-08:00

In computer science, polymorphism is a programming language feature that allows values of different data types to be handled using a uniform interface. The concept of parametric polymorphism applies to both data types and functions. A function that can evaluate to or be applied to values of different types is known as a polymorphic function. A data type that can appear to be of a generalized type (e.g., a list with elements of arbitrary type) is designated polymorphic data type like the generalized type from which such specializations are made.

The calling of a variety of operations using the same interface.

For example, a sub class can refine the implementation of a method or property inherited from its super class.

The property or method is there by redefined even if the super class is used as the interface class.

Thus, the logical device class can define the variable status as a string and can return the values “on” or “off”.

The modern sub class of logical device can redefine status by returning “on” or “off” and “connected”.

If all logical devices are enumerated any logical device that happens to be a modem can return the value “connected” for the status property.

Polymorphism enables a single method to exhibit different behaviors when used with different objects.

Method overloading is one form of polymorphism which a lows us to have two or more method declaration.

Example of overloading

Public overloads function find data (by val, name as srn as Array list find data and return result end function

Can be overloaded as shown below

Public overloads function find data (by val age as integer)

As array list find data and return result end function

Overloading constructers:

A constructor performs various. Tasks those are not visible to you as the programmer even if you were no code for the constructer. These tasks are all associated with building a complex.

Example

Public overloads sub new ()

Initialize object here

End sub

Public overloads sub new (by Val ID as integer)

Use the ID value to initialize the object

End sub

Explain event and event handlers

2010-12-29T01:32:00.001-08:00

The control classes such as buttons and edit boxes expose standard windows events such as click, key press, mouse move, drag drop and others.

You can work with an event in your application using delegates.

You do not have to understand delegates in great detail to work event handless in an application.

However, understanding how to create and use delegates is useful if you are building controls. Working with other application that trigger events or are using there ads with WFC components.

It is also interesting if you want to understand the details of the java code created by the forms designer

This section provides some background on delegates and then addresses the practical aspects of handling events.

If you want to handle events for multiple controls or multiple events for the same control, you request a separate notification for each control event combination you can use the source object passed to the event handler to get detail about.

Which button was clicked

ü Event driven programming

WINDOW APPLICATION

Allows you to create the windows, dialog boxes and controls in your application you draw and view controls on a form. While you are designing a form

Each form window has maximized, minimize and close button.

ü You can create either fixed or movable forms. The form you design will have the same features at designs time and as run time unless you specify otherwise in the forms properties.

ü Use the buttons in the toolbox to draw controls on the form.

ü Use the form layout window command from the view menu to preview the layout of your form on a screen.

ü The basic unit of the windows application is the form.

Artificial intelligence? Discuss briefly the history of artificial intelligence.

2010-12-29T01:31:00.000-08:00

Artificial intelligence (AI) is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its chances of success. John McCarthy, who coined the term in 1956 in organized the workshop at Dartmouth College. Defines, it as "the science and engineering of making intelligent machines." Where researches are interested in the field of automata theory, neural nets and study of intelligence proposed and adopted the name artificial intelligence for the field.

HISTORY OF ARTIFICAL INTELLIGENCE:

v In fact it is the different disciplines like philosophy, mathematics, economics, neuroscience, psychology, computer engineering, control theory and cybernetics and linguistics have contributed ideas, viewpoints and techniques to AI.

v It is Alan Turing who first proposed theory of computation.

v He proposed for the possibility of a computational machine that could behave in a way that could be perceived as intelligent.

v He developed a simple, universal and non numeric computing model which is capable of computing any computable function.

v Alan Twing (1936) is called the father of AI.

v Some of the diverse ideas / works that gave momentum to evolution of AI are listed below.

ü Allen’s theory of computation (1936)

ü Russel and whitehead’s principia mathematic

ü Wieners book on “cybernetics” (1948)

v AI has emerged as a separate field rather than a branch of other areas like mathematics operation research or decision theory.

v AI is the only field that laid emphasis on the methodology i.e. to build machines that can work in complex changing environment in an intelligent manner.

v Since 1956 researchers, industry people and scientists are succeeding in applying as in different areas like spacecrafts. Computer vision, media diagnosis, robotics, computer games, structural engineering, chemical and geological data analysis.

logical channel in groupe special mobile (GSM)

2010-12-29T01:26:00.000-08:00

Logical channels in GSM (groupe special mobile)

All the common channels are embedded in different traffic channels. They are grouped by the same cycle (51*8 BP). Where BP stands for burst period which is 517 rs

1). DOWN LINK COMMON CHANNELS

2). UP LINK COMMON CHANNELS

(1) DOWN LINK COMMON CHANNELS:

There are five downlink unidirectional channels shared or grouped by a TCH.

Ø Frequency collection channels (FCCH) repeats once every 51*8 BPS; used to identify a beacon frequency.

Ø Synchronization channels (SCH) follows each FCCH slot by 8 BPS.

Ø Broadcast control channels (BCCH) is broadcast regularly in each cell and received by all the mobile stations in the idle mode.

Ø Paging and access grant channel (PAGCH) issued for the incoming call received at the mobile station. The access grant channel is answered. From the base station and allocates a channel during the access procedure of setting up a call.

Ø Cell broadcast channel (CECH) each cell broadcasts a short message for 2 sec’s from the network to the mobile station in idle mode. Half a down link TCH 18 is used and special BCH design constraints exist because of the need for sending two channels is parallel.

Ø The mobile station (MS) finds the FCCH bursts then looks for an SCH burst on the same frequency to achieve synchronization. The MS then receive BCCH on several time slots and select a proper cell, remaining for a period in the idle mode.

(2) UP LINK COMMON CHANNELS:

The random-access channel (RACH) is the only common up link channel. RACH is the channel that the mobile station chooses to access the calls.

Ø Signaling channels:

All the signaling channels have one of the physical channels and the logical channels names are based on their logical functions.

Ø Slow associated control channel (SACCH)

A slow rate TCH used for signaling transport and used for non-urgent procedures mainly hand over decisions. It uses the eighth rate.

Ø Fast associated control channel (FACCH)

Indicator cell establishment authenticates subscribers or commands a hand over.

Ø Stand alone dedicated control channel (SDCCH)

Occasionally the connection between a mobile and the network is used slowly for passing signaling information and not for calls.

Ø Voice/ data channel

Each time slot of a voice channel contains 260 bits per block. The entire block contains 316 bits. Each time slot of a data channel contains 120 of 240 bits per block.

Digital Enhanced Cordless Telecommunications

2010-12-29T01:24:00.000-08:00

Digital Enhanced Cordless Telecommunications, usually known by the acronym DECT, is a digital communication standard, which is primarily used for creating cordless phone systems. It originated in Europe, where it is the universal standard, replacing earlier cordless phone standards, such as 900 MHz CT1 and CT2 DECT is European standard system. It is a CT-2 like system and the application are slightly different from the cellular system.

APPLICATIONS:

v Use the public network to mobile communication within the home and the immediate vicinity.

v Provide business communication locally. In this case, the PSTN has been removed the radio fixed point (RFP), also labeled or cluster controls.

v Local loop using DECT to provide wireless local loops is a cost effective alternative to running copper wires to residential premises.

SYSTEM STRUCTURE:

ü Duplex method – TDD

ü Access method – TDMA

ü RF power of handset – 10 MW

ü Channel bandwidth - 1728 MHz/ channel

ü Number of carriers - 5 (a multiple carrier system)

ü Frequency - 1800 MHz to 1900 MHz

CHARACTERISTICS:

ü Frame – 10 MS

ü Time slots - 12

ü Bit rates - 388 kb/ slot

ü Modulation - GFSK ( Gaussian fsk)

ü Hand off - YES

mobile integrated radio systems. [MIRS]

2010-12-29T01:23:00.000-08:00

MIRS is a cellular like system developer by Motorola to operate at the special mobile radio (SMR) band shown in the following figure.

Band	Mobile transmission	Base transmission
A cellular band A	829-835, 845-8465 MHz	869-880, 890-891 MHz
B cellular band B	869,880,890-891.5 MHz	880-890,891.5-895 MHz
ESMR	806-821 MHz	851-866 MHz

v MIRS system is called by the manufactures. The system providers call this system ESMR. The SMR band is in the part of FCC CFR in the private sector.

v Public information on this system is limited however the operational function is the same as the cellular system. Since many existing SMR system are still in operation the MIRS frequency channels in the SMR band are restricted depending on the area in which they operate. Therefore a special frequency assignment will be imposed in the MIRS system.

v Top level system specifications are as follows.

v Full duplex communication system frequency

- 806 to 824 MHz mobile transmitter

- 851 to 869 MHz base transmitter

v Channel band width – 25 MHz

v Multiple access – TDMA

v Number of time slots 0 6

v Rate of speech coders – 4.2 kbps / slot

v Modulation – 16 QAM

v Speech coders – VSELP

v No equalizer is implemented

v Hand off

v Transmission rate – 6.5 kbps/ slot

v Forward error correction – 3 kbps

v Inter leavens.

personal communication network. [PCN]

2010-12-29T01:22:00.001-08:00

The PCN system was first initiated by LORD YOUND in 1988. The characteristics of PCN are as follow.

v Operating frequency 1.7 to 1.88 GHz ( 1710-1785 MHz and 1805-1880 MHz)

v Uses 30 GHz or up for microwave back bone system.

v Covers both small cells and large cells.

v Coverage inside and outside buildings

v Hand over

v Call delivery

v Portable hand set

v User intelligent network

PCN uses the DCS – 1800 system. Which is similar to GSM but up converts the frequency to 1.7 to 1.88 GHz therefore the network structure the signal structure and the transmission characterize are similar between PCN and GSM but operation frequencies are different.

the parts of basic cellular system

2010-12-29T01:21:00.000-08:00

In a cellular communication system a geographical area as subdivided into small regions where each small region is called as a cell

A basic cellular system consist of three parts as listed below

- a mobile unit

- a cell site

- a mobile telephone switching office (MTSO)

The mobile unit (Mobile Telephone) contains a control unit, a transceiver (combination of transmitter and receiver) and on antenna sister.

Whenever a mobile unit wants to step a call it contents the cell site of the particular cell in which it exists at that time.

The cell site consists of control unit, antennas power plant and data terminals.

The cell site is infecting acting as an interface to the MTSO.

After the mobile unit contacts the cell site, the cell site in contacts the MTSO which processes the call further depending on whether it is a mobile to mobile call or mobile to fixed station call.

A little thought from the reader will indicate that a fixed subscriber to mobile call originates through the telephone exchange and passes through the MTSO and cell site towards the mobile unit.

Grade of Service (GOS)

2010-12-29T01:15:00.000-08:00

In loss systems, the traffic carried by the network is generally lower than the actual traffic offered to the network by the subscribers.

The overload traffic is rejected and hence is not carried by the network.

The amount of traffic rejected by the network is an index of the quality of the service offered by the network.

This is termed Grade of Service (GOS) and is defined as the ration of lost traffic to offered traffic.

Offered traffic is the product of the average number of calls generated by the users an average holding time per call.

On the other hand, the actual traffic carried by the network is called the carried traffic and is the average occupancy of the servers in the network.

GOS is given by

GOS= A – AO

Where

A = Offered traffic

AO = Carried traffic

A-AO = Lost traffic

The smaller the value of grade of service, the better is the service.

The recommended value for GOS in India is 0.002 which means that two calls in every 1000 calls or one call in every 500 calls may be lost.

Usually, every common subsystem in a network has an associated GOS value.

The GOS of the full network is determined by the highest GOS value of the subsystems in a simplistic sense.

A better estimate takes into account the connectivity of the subsystems, such as parallel units.

Since the volume of traffic grows as the time passes by the GOS value of a network deteriorates with time

In order to maintain the value within reasonable limits. Initially the network is sized to have a much smaller GOS value than the recommended one so that the GOS value continues to be within limits as the network traffic grows.

The blocking probability PB is defined as the probability that all the servers in a system are busy.

When all the servers are busy, no further traffic can be carried by the system and the arriving subscriber traffic is blocked.

At the first instance, it may appear that the blocking probability is the same measure as the GOS.

The probability that all the servers are busy may well represent the fraction of the calls lost, which is what the GOS is all about.

However, this is generally not true.

Example:

In a system with equal number of servers and subscribers. The GOS is zero as there is always a server available to subscriber.

multiplexing

2010-12-29T01:14:00.000-08:00

Multiplexing is the process where multiple channels are combined for transmission over a common transmission path.

Different types of multiplexing

There are two types of multiplexing.

(1) Frequency division multiplexing.

(2) Time division multiplexing.

(1) Frequency division multiplexing (FDM):

Frequency division multiplexing (FDM) is a scheme in which numerous signals are combined for transmission in a single communications line or channel. Each signal is assigned a different frequency within the main channel.

(2) Time division multiplexing (TDM):

Time division multiplexing (TDM) is a method of putting multiple data streams in a single signal by separating the signal into main segments, each having a very short duration. Each individual data stream is reassembled at the receiving end based on the timing.

Tone

2010-12-29T01:11:00.002-08:00

(A) BUSY TONE:

It is a burst 400 Hz signal with silence period in between. The burst and silence durations have the sum value of 0.755 or 0.3755. A busy tone is sent to the calling subscriber whenever the switching equipment or junction line is not available to put through the call or the called subscriber line is engaged no distinction is made between these conditions. It is not possible for a calling subscriber to conclude on the basis of the busy that the called party was actually engaged in a conversation.

(B) DIAL TONE:

This tone indicates that the exchange is ready to accept dialed digits from the subscribed. The subscriber should start dialing only after hearing the dial tone otherwise; initial dial pulses may be missed by the exchange. Which may result in the call landing on a wrong number Most often the dial tone is send out by the exchange even before the handset is brought near the ear. Sometimes however, a few seconds may elapse before the dial tone is heard this happens practically in common control exchange which is use shared resources for user interfaces. The dial tone is 33 Hz or 50 Hz or 400 Hz continuous tone.

(C) ROUTING TONE:

Routing tone or call-in-progress tone is a 400 Hz or 800 Hz intermittent pattern. It has 0.5 on/off period. In analog electronic exchanges it is a 400 Hz pattern with 0.5 on period and 2.5 off period. In digital exchanges it has 0.15 on/off periods at 400 Hz.Pride and Prejudice

simplex, half duplex and full duplex communication

2010-12-29T01:11:00.000-08:00

SIMPLEX COMMUNICATION:

In the simplex form of a telephone circuit, there is a one-way communication involving two entities. One receiving and the other transmitting this form of one way communication is known as simplex communication.

FULL DUPLEX COMMUNICATION:

An entity is capable of both receiving and sending although these do not take place simultaneously. An entity is either receiving or sending at any instant of time. When one entity is transmitting, the other is receiving and vice versa such or form of communication. Where the information transfers take places both directions simultaneously, then it is called full duplex communication.

HALF DUPLEX COMMUNICATION:

An entity is capable of both receiving and sending although these do not take place simultaneously. An entity is either receiving or sending at any instant of time. When one entity is transmitting, the other is receiving and vice versa such or form of communication. Where the information transfers take place both ways but not simultaneously is known as half-duplex communication.

FTP applications

2010-12-27T00:34:00.000-08:00

File Transfer Protocol (FTP) is a standard network protocol used to copy a file from one host to another over a TCP/IP-based network, such as the Internet. FTP is built on client-server architecture and utilizes separate control and data connections between the client and server. FTP users may authenticate themselves using a clear-text sign-in protocol but can connect anonymously if the server is configured to allow it.

Transferring a file via FTP requires two participants and FTP client program and FTP server program.

The FTP client is the program that we run on our computers.

The FTP server is the program that runs on the huge mainframe some where and stores tens thousands of files.

It is similar to an online library of files.

The FTP client can download or upload files to the FTP server.

Using web browser you can download the files but you can not upload the files.

There are many FTP programs that you can download from the internet.

FTP applications will help you to upload the files to the websites. Which you are maintain

Windows has its own command line based FTP program.

To execute it select run from windows taskbar and type FTP and press enter

By typing open command you can connect to any FTP server

To connect to FTP sever you must have a login name and the password.

Most of the FTP servers allow anonymous connections.

In this case username is anonymous and password is your email address.

To upload the files you can use input command.

To list the available commands you can type help

Another important FTP program, which is available as a shareware is WS FTP

Using this window based program it is easier to maintain your websites.

E-mail works

2010-12-27T00:33:00.000-08:00

The @ at sign, a part of every e-mail address

Electronic mail, commonly called email or e-mail, is a method of exchanging digital messages across the Internet or other computer networks. Originally, email was transmitted directly from one user to another computer. This required both computers to be online at the same time, a la instant messaging. Today's email systems are based on a store-and-forward model. Email servers accept, forward, deliver and store messages. Users no longer need be online simultaneously and need only connect briefly, typically to an email server, for as long as it takes to send or receive messages.

An email message consists of two components, the message header, and the message body, which is the e-mail’s content. The message header contains control information, including, minimally, an originator's email address and one or more recipient addresses. Usually additional information is added, such as a subject header field.

v To understand this let us assume person a sends a mail to b.

v The bgl sever checks the network of a mail server with the lowest traffic and upload a mail to this server.

v This server in turn holds the mail while checking the network for a mail server with the lowest activity and uploads a mail there.

v This process continues until the mail is uploaded to hotmail server into b mailbox

v The recipient downloads it from the destination mail sever

v Email works in the same way as the postal system does

v When you write an email message and mail it. It gets posted in the mail server which could be on your private network or the internet

v This is analogy to your local post office where all your letters end up after. You deposit them in the letterbox.

v The mail server also plays or large parts in controlling the data traffic on the network.

v It stores messages when network traffic is high and forwards them when network traffic is low there by reducing network congestion.

v It also acts as a gateway or a translator between different types of email system like the internets POP3 or *400.

v Once the message reaches the destination mail server. They are stored until the recipient collects it.

TCP / IP

2010-12-27T00:32:00.000-08:00

The TCP/IP model, or Internet Protocol Suite, describes a set of general design guidelines and implementations of specific networking protocols to enable computers to communicate over a network. TCP/IP provides end-to-end connectivity specifying how data should be formatted, addressed, transmitted, routed and received at the destination. Protocols exist for a variety of different types of communication services between computers.

v Across the internet, hundreds of different programs run on innumerable computers and operating systems.

v For such programs to interact correctly they must follow a set of rules. These rules are called protocols.

v A protocol is a formal description of message format and the rules two or more computers must follow to exchanges those messages.

v Protocols can describe the low-level details of computer – to – computer interfaces. The TCP/IP is a suite of protocols used in the internet.

v TCP/IP is a set of rules that an application can use to package its information for searching across the network or networks.

v The OSI reference model has seven layers.

1. Application

2. Presentation

3. Session

4. Transport

5. Network

6. Data link

7. Physical

v The internet uses the TCP/IP as its protocol engine and this uses only five of the ISO/OSI layer set application, transport, network, data line and physical.

what is internet

2010-12-27T00:30:00.000-08:00

The Internet is a global system of interconnected computer networks that use the standard Internet Protocol Suite (TCP/IP) to serve billions of users worldwide. It is a network of networks that consists of millions of private, public, academic, business, and government networks, of local to global scope, that are linked by a broad array of electronic and optical networking technologies.

§ It is a set of computers talking over fiber optics phone lines, satellite links and other media.

§ It is a place where you can talk to your friends and family around the world.

§ It is a place to get cool game demos.

§ It is an ocean of resources waiting to be mined.

§ It is a place to do research for your thesis or a business presentation.

§ It is an unlimited commercial opportunity.

§ It is a worldwide support group for any problem or need.

§ It is a goldmine of professionals in all fields sharing information about their work.

§ It is the collection of hundreds of libraries and archives that will open to your fingertips.

§ It is an ultimate time-wasted.

§ It is the technology of the future that will help make our lives and those of our children brighter.