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Members - IT girls Google Groups

what is Payload?

When data is sent over the Internet, each unit transmitted includes both header information and the actual data being sent. The header identifies the source and destination of the packet, while the actual data is referred to as the payload. Because header information, or overhead data, is only used in the transmission process, it is stripped from the packet when it reaches its destination. Therefore, the payload is the only data received by the destination system.

Take advantage of the benefits of loosely coupled Web services:
Loosely coupled components can operate independently of each other with no problems. This is an excellent fit when designing Web services, where all components are not always available. Coupling generally refers to the act of joining two things together, such as the links in a chain. But in software development, coupling typically refers to the degree to which software components/modules depend upon each other. The degree to which components are linked defines whether they operate in a tightly coupled relationship or in a loosely coupled relationship. With tightly coupled components, each component and any auxiliary dependent objects must be present at execution time as well as compile time. On the other hand, loosely coupled components can operate independently from one another.

The benefits of location transparency in an SOA:

1. Chief among the benefits of a service oriented architecture is that services and clients operate independently of their locations, known as location transparency. Learn some of the advantages of using it and also a few issues that could arise.
2. One of the major benefits provided by a service oriented architecture (SOA) is the decoupling of the client requesting the service and the service itself.
3. Through a registration and discovery mechanism, the SOA provides location transparency, which allows clients to not know (or care) about where a component or service is actually located.

Difference between URL,URN,URI.
URL
The idea is that a URL is a mechanical link to a resource's location, where it can be downloaded. For this reason, a URL contains a hostname and a local part, all of which can be resolved anywhere on the Internet.URL
A URL is a specialization of URI that defines the network location of a specific resource. Unlike a URN, the URL defines how the resource can be obtained. We use URLs every day in the form of http://damnhandy.com, etc. But a URL doesn’t have to be an HTTP URL, it can be ftp://damnhandy.com, smb://damnhandy.com, etc.
URI
A URI identifies a resource either by location, or a name, or both. More often than not, most of us use URIs that defines a location to a resource. The fact that a URI can identify a resources by both name and location has lead to a lot of the confusion in my opionion. A URI has two specializations known as URL and URN.
URN
What a URN tries to do is different. It tries to give a description of a resource without actually pointing at it. For example:urn:isbn:90-365-17273
A URI identifies a resource by name in a given namespace but not define how the resource maybe obtained. This type of URI is called a URN.
URI is merely the possibly overlapping union of strings that are a URL or a URN

The SSL protocol was originally developed by Netscape, to ensure security of data transported and routed through HTTP, LDAP or POP3 application layers. SSL is designed to make use of TCP as a communication layer to provide a reliable end-to-end secure and authenticated connection between two points over a network (for example between the service client and the server).
The main objectives for SSL are:
Authenticating the client and server to each other: the SSL protocol supports the use of standard key cryptographic techniques (public key encryption) to authenticate the communicating parties to each other. Though the most frequent application consists in authenticating the service client on the basis of a certificate, SSL may also use the same methods to authenticate the client.
Ensuring data integrity: during a session, data cannot be either intentionally or unintentionally tampered with.
Securing data privacy: data in transport between the client and the server must be protected from interception and be readable only by the intended recipient. This prerequisite is necessary for both the data associated with the protocol itself (securing traffic during negotiations) and the application data that is sent during the session itself. SSL is in fact not a single protocol but rather a set of protocols that can additionally be further divided in two layers:
the protocol to ensure data security and integrity: this layer is composed of the SSL Record Protocol,
The protocols that are designed to establish an SSL connection: three protocols are used in this layer: the SSL Handshake Protocol, the SSL ChangeCipher SpecPprotocol and the SSL Alert Protocol. The SSL record protocol is responsible for data encryption and integrity. It is also used to encapsulate data sent by other SSL protocols, and therefore, it is also involved in the tasks associated with the SSL check data. The other three protocols cover the areas of session management, cryptographic parameter management and transfer of SSL messages between the client and the server. Prior to going into a more detailed discussion of the role of individual protocols and their functions let us describe two fundamental concepts related to the use of SSL.

Difference Between HTTP and HTTPS:

• HTTP utilizes tcp/udp (Transmission Control Protocol/User Datagram Protocol) port 80 to transfer packets for unencrypted web surfing. If you visit a website or webpage, and look at the address in the web browser, it will most likely begin with the following: http://. This means that the website is connected to your browser using the regular unsecure language, due to which there is a possiblilty for someone to spy on your computer’s conversation with the website. If you fill out a form on the website, someone might see the information you send to that site.
• HTTPS The "S" in HTTPS indicates a secure site. It is utilizes tcp/udp port 443 for encrypted web surfing via SSL (Secure Sockets Layer) or the more recent TLS (Transport Layer Security) protocols. HTTPS provides for reasonably secure bi-directional encrypted communication on the Internet. Https is used in many situations, such as log-in pages for banking, forms, corporate log ons, and other applications in which data needs to be secure. However, if not implemented properly, https is not infallible, and therefore it is extremely important for end users to be wary about accepting questionable certificates and cautious with their personal information while using the Internet.

location transperency:
In computer networks location transparency describes names used to identify network resources independent of both the user's location and the resource location.
A distributed system will need to employ a networked scheme for naming resources.
In other words it is an idea that the resources can be accessed by a user from anywhere on the network without knowing where the resource is located. A file could be on the user's own PC, or thousands of miles away on other servers.
url:
Uniform Resource Locator is a compact string of characters used to represent a resource available on the Internet.[1] In popular usage and many technical documents, it is a synonym for Uniform Resource Identifier (URI).
uri:
a Uniform Resource Identifier (URI) is a compact string of characters used to identify or name a resource on the Internet. The main purpose of this identification is to enable interaction with representations of the resource over a network, typically the World Wide Web, using specific protocols. URIs are defined in schemes defining a specific syntax and associated protocols.
urn:
A Uniform Resource Name (URN) is a Uniform Resource Identifier (URI) that uses the urn scheme, and does not imply availability of the identified resource. Both URNs (names) and URLs (locators) are URIs, and a particular URI may be a name and a locator at the same time.

SECURE SOCKET LAYER(SSL):How It Works

Secure Sockets Layer (SSL) technology protects your Web site and makes it easy for your Web site visitors to trust you in three essential ways:
1.An SSL Certificate enables encryption of sensitive information during online transactions.
2.Each SSL Certificate contains unique, authenticated information about the certificate owner.
3.A Certificate Authority verifies the identity of the certificate owner when it is issued.

SECURE SOCKET LAYER

The Secure Sockets Layer (SSL) is a commonly-used protocol for managing the security of a message transmission on the Internet. SSL has recently been succeeded by Transport Layer Security (TLS), which is based on SSL. SSL uses a program layer located between the Internet's Hypertext Transfer Protocol (HTTP) and Transport Control Protocol (TCP) layers. SSL is included as part of both the Microsoft and Netscape browsers and most Web server products. Developed by Netscape, SSL also gained the support of Microsoft and other Internet client/server developers as well and became the de facto standard until evolving into Transport Layer Security. The "sockets" part of the term refers to the sockets method of passing data back and forth between a client and a server program in a network or between program layers in the same computer. SSL uses the public-and-private key encryption system from RSA, which also includes the use of a digital certificate.

Dynamic Link Library

Dynamic-link library (also written without the hyphen), or DLL, is Microsoft's implementation of the shared library concept in the Microsoft Windows and OS/2 operating systems. These libraries usually have the file extension DLL, OCX (for libraries containing ActiveX controls), or DRV (for legacy system drivers). The file formats for DLLs are the same as for Windows EXE files — that is, Portable Executable (PE) for 32-bit and 64-bit Windows, and New Executable (NE) for 16-bit Windows. As with EXEs, DLLs can contain code, data, and resources, in any combination.

Features of DLL

Memory management
In Win32, the DLL files are organized into sections. Each section has its own set of attributes, such as being writable or read-only, executable (for code) or non-executable (for data), and so on.
The code in a DLL is usually shared among all the processes that use the DLL; that is, they occupy a single place in physical memory, and do not take up space in the page file. If the physical memory occupied by a code section is to be reclaimed, its contents are discarded, and later reloaded directly from the DLL file as necessary.

In contrast to code sections, the data sections of a DLL are usually private; that is, each process using the DLL has its own copy of all the DLL's data. Optionally, data sections can be made shared, allowing inter-process communication via this shared memory area. However, because user restrictions do not apply to the use of shared DLL memory, this creates a security hole; namely, one process can corrupt the shared data, which will likely cause all other sharing processes to behave undesirably. For example, a process running under a guest account can in this way corrupt another process running under a privileged account. This is an important reason to avoid the use of shared sections in DLLs.

If a DLL is compressed by certain executable packers (e.g. UPX), all of its code sections are marked as read-and-write, and will be unshared. Read-and-write code sections, much like private data sections, are private to each process. Thus DLLs with shared data sections should not be compressed if they are intended to be used simultaneously by multiple programs, since each program instance would have to carry its own copy of the DLL, resulting in increased memory consumption.

XSD Restrictions/Facets

When an XML element or attribute has a data type defined, it puts restrictions on the element's or attribute's content.
If an XML element is of type "xs:date" and contains a string like "Hello World", the element will not validate.
With XML Schemas, you can also add your own restrictions to your XML elements and attributes. These restrictions are called facets.

In otherwards,Restrictions are used to define acceptable values for XML elements or attributes. Restrictions on XML elements are called facets.

The following type of restrictions are allowed in xml schema:
Restrictions on Values
Restrictions on a Series of Values
Restrictions on Whitespace Characters
Restrictions on Length
Restrictions for Datatypes and
Other Restrictions on a Series of Values

Definition For COM

Component Object Model (COM) is Microsoft's framework for developing and supporting program component objects. It is aimed at providing similar capabilities to those defined in the Common Object Request Broker Architecture (CORBA), a framework for the interoperation of distributed objects in a network that is supported by other major companies in the computer industry. Whereas Microsoft's Object Linking and Embedding provides services for the compound document that users see on their display, COM provides the underlying services of interface negotiation, life cycle management (determining when an object can be removed from a system), licensing, and event services (putting one object into service as the result of an event that has happened to another object).

OVERVIEW OF CORBA

The Common Object Request Broker Architecture (CORBA) [OMG:95a] is an emerging open distributed object computing infrastructure being standardized by the Object Management Group (OMG). CORBA automates many common network programming tasks such as object registration, location, and activation; request demultiplexing; framing and error-handling; parameter marshalling and demarshalling; and operation dispatching. See the OMG Web site for more overview material on CORBA.

COM

Component Object Model (COM) is a Microsoft centric interface standard for software componentry introduced by Microsoft in 1993. It is used to enable interprocess communication and dynamic object creation in any programming language that supports the technology.  The term COM is often used in software development industry as an umbrella term that encompasses the OLE,OLE Automation, COM+ and DCOM technologies.

Please refer to the below link for further details.

http://msdn.microsoft.com/en-us/library/ms809980.aspx.

CORBA

The Common Object Request Broker Architecture (CORBA) is a standard defined by the Object Management Group (OMG) that enables software components written in multiple computer languages and running on multiple computers to work together.

CORBA is a mechanism in software for normalizing the method call semantics between application objects that reside either in the same address space (application) or remote address space (same host or remote host on a network).

Dynamic Link Library(DLL)

A dynamic-link library (DLL) is an executable file that acts as a shared library of functions. Dynamic linking provides a way for a process to call a function that is not part of its executable code. The executable code for the function is located in a DLL, which contains one or more functions that are compiled, linked, and stored separately from the processes that use them. DLLs also facilitate the sharing of data and resources. Multiple applications can simultaneously access the contents of a single copy of a DLL in memory.
Dynamic linking differs from static linking in that it allows an executable module (either a .dll or .exe file) to include only the information needed at run time to locate the executable code for a DLL function. In static linking, the linker gets all of the referenced functions from the static link library and places it with your code into your executable.
Using dynamic linking instead of static linking offers several advantages. DLLs save memory, reduce swapping, save disk space, upgrade easier, provide after-market support, provide a mechanism to extend the MFC library classes, support multilanguage programs, and ease the creation of international versions.

Document Object model(DOM)

The Document Object Model (DOM) is a platform- and language-independent standard object model for representing HTML or XML and related formats.
The XML DOM (Document Object Model) defines a standard way for accessing and manipulating XML documents.

The Common Object Request Broker Architecture (CORBA) is a standard defined by the Object Management Group (OMG) that enables software components written in multiple computer languages and running on multiple computers to work together.

please go through this link http://www.omg.org/gettingstarted/corbafaq.htm

Dyanamic Link Library

IT is a library of executable functions or data that can be used by a Windows application. Typically, a DLL provides one or more particular functions and a program accesses the functions by creating either a static or dynamic link to the DLL. A static link remains constant during program execution while a dynamic link is created by the program as needed. DLLs can also contain just data. DLL files usually end with the extension .dll,.exe., drv, or .fon.

Facets in XML Schema

Restrictions are used to define acceptable values for XML elements or attributes. Restrictions on XML elements are called facets.

XML Schemas are the Successors of DTDs

XML Schemas are the Successors of DTDs
We think that very soon XML Schemas will be used in most Web applications as a replacement for DTDs. Here are some reasons:
XML Schemas are extensible to future additions
XML Schemas are richer and more powerful than DTDs
XML Schemas are written in XML
XML Schemas support data types
XML Schemas support namespaces

XML Schema

Please go through this tutorial for XML Schema from w3schools.

http://www.w3schools.com/schema/schema_intro.asp

The Benefits of XSLT

Extensible Stylesheet Language(XSLT) gives you all the traditional benefits of a high-level declarative programming language, specialized to the task of transforming XML documents.
The usual benefit cited for higher-level languages is development productivity. An XSLT application for transforming XML data structures can be made much more resilient to changes in the details of the XML documents than a procedural application coded using the low-level DOM and SAX interfaces. In the database world this feature is known as data independence, and it was the quest for data independence that led to the success of declarative languages like SQL and the demise of the older navigational data access languages. I firmly believe the same will happen in the XML world.
As with all declarative languages, there is a performance penalty. But for the vast majority of applications, the performance of today's XSLT processors is already good enough to meet the application requirements, and it is getting better.

USE OF SCRIPTING LANGUAGE

Scripting languages assume that there already exists a collection of useful components written in other languages.
Scripting languages aren't intended for writing applications from scratch; they are intended primarily for plugging together components.
Scripting languages such as Perl,Visual Basic, and the Unix shells represent a very different style of programming than system programming languages.
In order to simplify the task of connecting components, scripting languages tend to be typeless.A typeless language makes it much easier to hook together components.

Why Use a DTD?

1. With a DTD, each of your XML files can carry a description of its own format.
2. With a DTD, independent groups of people can agree to use a standard DTD for interchanging data.
3. Your application can use a standard DTD to verify that the data you receive from the outside world is valid.
4. You can also use a DTD to verify your own data.

Entity

Entities are simply a data-replacement facility.
For Example: An entity declaration says, "wherever you see X, replace it with Y". Then, you sprinkle a bunch of X's around your document, which are the entity references. When the XML parser sees an X, it mentally substitutes Y in its place.

Parsed vs. Unparsed Entities

Entities may be either parsed or unparsed. A parsed entity's contents are referred to as its replacement text; this text is considered an integral part of the document. An unparsed entity is a resource whose contents may or may not be text, and if text, may not be XML. Each unparsed entity has an associated notation, identified by name. Beyond a requirement that an XML processor make the identifiers for the entity and notation available to the application, XML places no constraints on the contents of unparsed entities. Parsed entities are invoked by name using entity references; unparsed entities by name, given in the value of ENTITY or ENTITIES attributes.

DOCUMENT TYPE DEFINITION:
A Document Type Definition (DTD) defines the legal building blocks of an XML document. It defines the document structure with a list of legal elements and attributes.
A DTD can be declared inline inside an XML document, or as an external reference.

Internal DTD Declaration:
If the DTD is declared inside the XML file, it should be wrapped in a DOCTYPE definition with the following syntax:


External DTD Declaration:
If the DTD is declared in an external file, it should be wrapped in a DOCTYPE definition with the following syntax:

The DTD can contain several different types of declarations:

1. Element declarations let you specify what kinds of tags can be used, and what (if anything) can appear inside the contents of the element.
2. Attribute declarations define what attributes you can use inside a given element.
3. Entity declarations define chunks of fixed text that can be included elsewhere.
4. Notation declarations define file types (like JPG and WAV files) so you can refer to non-XML files like image and sound files.

DOCTYPE Declaration & DTDs

The document type (DOCTYPE) declaration consists of an internal, or references an external Document Type Definition (DTD). It can also have a combination of both internal and external DTDs. The DTD defines the constraints on the structure of an XML document. It declares all of the document's element types, children element types, and the order and number of each element type. It also declares any attributes, entities, notations, processing instructions, comments, and PE references in the document.

External DTD

The benefits of using external DTDs is that they can more easily and efficiently be shared by more than one XML document, or in fact, many organizations with the need to standardize communications and data. You can write a DTD once and have multiple documents reference it. Not only does this save typing time, but it assures that as the DTD manager makes changes to the central DTD, all documents that rely on the DTD are updated in one fell swoop. (Of course, DTD changes will not necessarily be backwards compatible, so watch out!).
In order to reference an external DTD, you must change both the XML declaration and the DOCTYPE declaration.

XML schema

An XML Schema:

defines elements that can appear in a document
defines attributes that can appear in a document
defines which elements are child elements
defines the order of child elements
defines the number of child elements
defines whether an element is empty or can include text
defines data types for elements and attributes
defines default and fixed values for elements and attributes

Definition of DTD

A Document Type Definition (DTD) defines the legal building blocks of an XML document. It defines the document structure with a list of legal elements and attributes.

A DTD can be declared inline inside an XML document, or as an external reference.

VB script -basic concept

What is VBScript?
VBScript is a scripting language
A scripting language is a lightweight programming language
VBScript is a light version of Microsoft's programming language Visual Basic

How Does it Work?
When a VBScript is inserted into a HTML document, the Internet browser will read the HTML and interpret the VBScript. The VBScript can be executed immediately, or at a later event.

PCDATA - Parsed Character Data:
XML parsers normally parse all the text in an XML document.
When an XML element is parsed, the text between the XML tags is also parsed:

Four key original design goals for Unicode :

1. To create a universal standard that covered all writing systems.
2. To use an efficient encoding that avoided mechanisms such as code page switching, shift-sequences and special states.
3. To use a uniform encoding width in which each character was encoded as a 16-bit value.
4. To create an unambiguous encoding in which any given 16-bit value always represented the same character regardless of where it occurred in the data.

Types of scripting languages

1. Job control languages and shells
2. GUI Scripting
3. Application-specific languages
4. Web browsers
5. Web servers
6. Text processing languages
7. General-purpose dynamic languages
8. Extension/embeddable languages

Java script

A scripting language developed by Netscape to enable Web authors to design interactive sites. Although it shares many of the features and structures of the full Java language, it was developed independently. Javascript can interact with HTML source code, enabling Web authors to spice up their sites with dynamic content. JavaScript is endorsed by a number of software companies and is an open language that anyone can use without purchasing a license. It is supported by recent browsers from Netscape and Microsoft, though Internet Explorer supports only a subset, which Microsoft calls Jscript.

What is scripting?

Scripts may be evaluated as a document loads to modify the contents of the document dynamically.

Scripts may accompany a form to process input as it is entered. Designers may dynamically fill out parts of a form based on the values of other fields. They may also ensure that input data conforms to predetermined ranges of values, that fields are mutually consistent, etc.

Scripts may be triggered by events that affect the document, such as loading, unloading, element focus, mouse movement, etc.

Scripts may be linked to form controls (e.g., buttons) to produce graphical user interface elements.

Roles in the Mainframe
Mainframe systems are designed to be used by large numbers of people. Most of those who interact with mainframes are end users— people who use the applications that are hosted on the system. However, because of the large number of end users, applications running on the system, and the sophistication and complexity of the system software that supports the users and applications, a variety of roles are needed to operate and support the system.
For Example:
In the IT field, these roles are referred to by a number of different titles, such as:
System programmers
System administrators
Application designers and programmers
System operators
Production control analysts

JavaScript Java


Interpreted (not compiled) by client. Compiled bytecodes downloaded from server,
executed on client.

Object-based. Uses built-in, extensible Object-oriented. Applets consist of
objects, but no classes or inheritance. object classes with inheritance

Code integrated with, and embedded Applets distinct from HTML
in, HTML. (accessed from HTML pages).

Variable data types not declared Variable data types must be
(loose typing). declared (strong typing).


Dynamic binding. Object references Static binding. Object references must
checked at runtime. exist at compile-time.


Cannot automatically write to hard Cannot automatically write to hard
disk. disk.

WAT IS JavaScript

JavaScript is a scripting language most often used for client-side web development. It was the originating dialect of the ECMAScript standard. It is a dynamic, weakly typed, prototype-based language with first-class functions. JavaScript was influenced by many languages and was designed to look like Java, but be easier for non-programmers to work with .JavaScript is also used to enable scripting access to objects embedded in other applications (see below).
JavaScript, despite the name, is essentially unrelated to the Java programming language, although both have the common C syntax, and JavaScript copies many Java names and naming conventions. The language was originally named "LiveScript" but was renamed in a co-marketing deal between Netscape and Sun, in exchange for Netscape bundling Sun's Java runtime with their then-dominant browser. The key design principles within JavaScript are inherited from the Self programming language."JavaScript" is a trademark of Sun Microsystems.

What is JavaScript?

JavaScript is Netscape's cross-platform, object-based scripting language for client and server applications. There are two types of JavaScript:

Navigator JavaScript, also called client-side JavaScript
LiveWire JavaScript, also called server-side JavaScript

What is Scripting language?
A scripting language, script language or extension language, is a programming language that controls a software application. "Scripts" are often treated as distinct from "programs", which execute independently from any other application. At the same time they are distinct from the core code of the application, which is usually written in a different language, and by being accessible to the end user they enable the behavior of the application to be adapted to the user's needs. Scripts are often, but not always, interpreted from the source code or "semi-compiled" to bytecode which is interpreted, unlike the applications they are associated with, which are traditionally compiled to native machine code for the system on which they run. Scripting languages are nearly always embedded in the application with which they are associated.

About Unicode

Unicode provides a unique number for every character, no matter what the platform, no matter what the program, no matter what the language. The Unicode Standard has been adopted by such industry leaders as Apple, HP, IBM, JustSystems, Microsoft, Oracle, SAP, Sun, Sybase, Unisys and many others. Unicode is required by modern standards such as XML, Java, ECMAScript (JavaScript), LDAP, CORBA 3.0, WML, etc., and is the official way to implement ISO/IEC 10646. It is supported in many operating systems, all modern browsers, and many other products.
Incorporating Unicode into client-server or multi-tiered applications and websites offers significant cost savings over the use of legacy character sets. Unicode enables a single software product or a single website to be targeted across multiple platforms, languages and countries without re-engineering. It allows data to be transported through many different systems without corruption.

What is a mainframe?

Mainframe is a computer that supports dozens of applications and input/output devices to serve tens of thousands of users simultaneously.The general term "mainframe" refers to large computers like those in the IBM System z9 and eServer zSeries processor families.What separates the mainframe from other computers is not just its processing capabilities. A mainframe has redundant features and system health awareness capabilities that enable it to deliver 99.999% availability.Mainframes are used by large organizations as their central transaction processing system. Transaction processing in this context requires high availability, security, performance, and responsiveness.

Capabilities of Mainframe

Mainframe architecture includes a variety of network capabilities. Some of these capabilities include:

• IP communication among large numbers of Linux and operating systems running as Virtual machine.
• IP communication among independent operating systems running in logical partitions the same machine .
• System Network Architecture suite of protocols and equipment, including subarea and Advanced Peer-to-Peer Networking with high performance routing.
• Integration of SNA into IP networks using Enterprise technology.

Unicode

A universal character set that defines the characters included in a majority of the languages of the world. It can work with pages and forms that include a mixture of languages within the same page.
ISO-8859-1
Also know as Latin1, includes the latin based languages of the world. It includes most western european languges.

Characteristics of mainframes

1) Reliable single-thread performance, which is essential for reasonable operations against a database.
2) Maximum I/O connectivity, which means mainframes excel at providing for huge disk farms.
3) Maximum I/O bandwidth, so connections between drives and processors have few choke-points.
4) Reliability--mainframes often allow for "graceful degradation" and service while the system is running.

Mainframes

A very large and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously. In the hierarchy that starts with a simple microprocessor (in watches, for example) at the bottom and moves to supercomputers at the top, mainframes are just below supercomputers. In some ways, mainframes are more powerful than supercomputers because they support more simultaneous programs. But supercomputers can execute a single program faster than a mainframe. The distinction between small mainframes and minicomputers is vague, depending really on how the manufacturer wants to market its machines

what classifies a computer as a mainframe?

1. A mainframe has 1 to 16 CPU's (modern machines more)
2. Memory ranges from 128 Mb over 8 Gigabyte on line RAM
3. Its processing power ranges from 80 over 550 Mips
4. It has often different cabinets for
   Storage
   I/O
   RAM
5. Separate processes (program) for
   task management
   program management
   job management
   serialization
   catalogs
   inter address space
   communication

Historically, a mainframe is associated with centralized computing opposite from distributed computing. Meaning all computing takes (physically) place on the mainframe itself.

Mainframe Definition

Mainframes (often colloquially referred to as Big Iron) are computers used mainly by large organizations for critical applications, typically bulk data processing such as census, industry and consumer statistics and financial transaction processing.The term probably originated from the early mainframes, as they were housed in enormous, room-sized metal boxes or frames. Later the term was used to distinguish high-end commercial machines from less powerful units which were often contained in smaller packages.

MAINFRAME COMPUTERS

A mainframe is a large powerful computer that serves many users (hundreds) simultaneously and is sued by large companies for bulk data processing, running several programs simultaneously and sharing of resources amongst the organisations various computer users.
The term ‘mainframe’ was coined in the 1970s when the smaller minicomputers began available. In those days mainframes were huge and could occupy a whole room or take out an entire floor. Today mainframes have decreased in size nut with in an increase in computing power and are sometimes referred to as large servers.
In the 1960s and the 1970s, mainframes were popular, with quite a number of manufacturers, but the arrival of the cheaper microcomputers and the concept of distributed computing reduced the demand for mainframes and a lot of the companies went under.

Why would you want to use a proxy? As I mentioned before, for security. If you are using a good proxy, the web sites you visit will not be able to tell who you actually are, or where you actually came from. For example, if you use a proxy and visit the "Snoop Page", the page most likely will not be able to gather accurate information on your connection.

What is a Proxy Server?
The technical definition for "Proxy": The technique in which one host, usually a router, answers Address Resolution Protocol (ARP) requests intended for another machine. By "faking" its identity, the router accepts responsibility for routing packets to the "real" destination. Proxy ARP allows a site to use a single IP address with two physical networks. A proxy is a server that will act as the "middle-man" between you and whatever else you connect to. It is most commonly used as a "safety net" for your connection. Using a proxy usually hides the true identity of the person using it.

Function of the Web Browser

The function of the web browser is transferring the hypertext.But many have specific features that are unique.Web browser acts as an interface between user and the inner workings of the internet,specifically www.
It also referred to as web clients or universal clients,because in the client/server model,the browser functions as the client program.
Web Browser can be of two types
1.Text based(view only text)
2.Graphical based(allows user to see more of what the www has to offer suchas graphics,photos and multimedia)
Some common browsers are:

• Mosaic
• Opera
• Amaya
• Hot Java
• Lynx(Text based)

what is www?

The World Wide Web (commonly shortened to the Web) is a system of interlinked hypertext documents accessed via the Internet. With a Web browser, a user views Web pages that may contain text, images, videos, and other multimedia and navigates between them using hyperlinks. The World Wide Web was created in 1989 by Sir Tim Berners-Lee, working at the European Organization for Nuclear Research (CERN) in Geneva, Switzerland and released in 1992. Since then, Berners-Lee has played an active role in guiding the development of Web standards (such as the markup languages in which Web pages are composed), and in recent years has advocated his vision of a Semantic Web.

what is internet?

internet is nothing but networks of network with which we can share the information across globe.the world wide web uses internet to privide the information.

Application Server:

An application server is a server program in a computer in a distributed network that provides the business logic for an application program. The application server is frequently viewed as part of a three-tier application, consisting of a graphical user interface (GUI) server, an application (business logic) server, and a database and transaction server. More descriptively, it can be viewed as dividing an application into:
A first-tier, front-end, Web browser-based graphical user interface, usually at a personal computer or workstation
A middle-tier business logic application or set of applications, possibly on a local area network or intranet server
A third-tier, back-end, database and transaction server, sometimes on a mainframe or large server

Advantage Of XML

Advantages:
The first benefit of XML is that because you are writing your own markup language, you are not restricted to a limited set of tags defined by proprietary vendors.Searching the data is easy and efficient. The code is much more legible to a person coming into the environment with no prior knowledge. In the above example, it is obvious that 002 represents an ID whereas

002 might not. XML is self-describing.

Additional specifications of Web Service

Some specifications have been developed or are currently being developed to extend Web Services capabilities. These specifications are generally referred to as WS-*. Here is a non-exhaustive list of these WS-* specifications.
WS-Security
Defines how to use XML Encryption and XML Signature in SOAP to secure message exchanges, as an alternative or extension to using HTTPS to secure the channel.
WS-Reliability
An OASIS standard protocol for reliable messaging between two Web services.
WS-Transaction
A way of handling transactions.

Types of Server

Application Server:-Sometimes referred to as a type of middleware, application servers occupy a large chunk of computing territory between database servers and the end user, and they often connect the two.
Audio/Video servers:-It bring multimedia capabilities to Web sites by enabling them to broadcast streaming multimedia content.
Chatservers :-It enable a large number of users to exchange information in an environment similar to Internet newsgroups that offer real-time discussion capabilities.
Fax server:-It is an ideal solution for organizations looking to reduce incoming and outgoing telephone resources but that need to fax actual documents.
One of the oldest of the Internet services, File Transfer Protocol makes it possible to move one or more files securely between computers while providing file security and organization as well as transfer control.
Proxy Servers:-Proxy servers sit between a client program (typically a Web browser) and an external server (typically another server on the Web) to filter requests, improve performance, and share connections.
Telnet server :-It enables users to log on to a host computer and perform tasks as if they're working on the remote computer itself.

Web service

A 'Web service' is defined by the W3C as "a software system designed to support interoperable Machine to Machine interaction over a network". Web services are frequently just Web APIs that can be accessed over a network, such as the Internet, and executed on a remote system hosting the requested services.
The W3C Web service definition encompasses many different systems, but in common usage the term refers to clients and servers that communicate using XML messages that follow the SOAP standard. In such systems, there is often machine-readable description of the operations offered by the service written in the Web Services Description Language (WSDL)

What is Server?

A Server is a computer or device on a network that manages network resources. For example, a file server is a computer and storage device dedicated to storing files Any user on the network can store files on the server. A print server is a computer that manages one or more printers and a network server is a computer that manages network traffic.

what services can be offered?

What services can be offered?
A service is any application that is accessed by means of a URL for example Google. The output of a service may be XML, HTML an image etc. And in some cases the output of a service may be used as input to other services or as a query for the portal. Examples of integration of services in the portal are:
*a Google image search with an author name as search parameter
*annotation of records
In some cases the result of a link to a service is a web page ,in other cases the results can be integrated in the presentation (like an image or XML with a known schema). It may also possible to process the output of a service with a known HTML layout and make the results available to the portal. It is obvious that there are not very many restrictions in what type of services can potentially be offered to the user. Besides that a lot of intelligence can be added to the portal in dealing with these services in an appropriate way. For example some services might be accessed automatically based on other criteria than only the presence of a metadata field

What is Meant by XML?

XML is a set of rules for designing text formats that let you structure your data. XML is not a programming language, and you don't have to be a programmer to use it or learn it. XML makes it easy for a computer to generate data, read data, and ensure that the data structure is unambiguous. XML avoids common pitfalls in language design: it is extensible, platform-independent.

Usage of web services

Web services are a new breed of Web application. They are self-contained, self-describing, modular applications that can be published, located, and invoked across the Web. Web services perform functions, which can be anything from simple requests to complicated business processes...Once a Web service is deployed, other applications (and other Web services) can discover and invoke the deployed service.

Thick vs. Thin Client Applications
Thin client :
1. A thin client machine is going to communicate with a central processing server.
2. Thin may be defined as simply not needing the software or operating system installed on the user machine
3. This allows all end users' systems to be centrally managed and software deployed on a central server location as opposed to installed on each individual system.
Thick client :
1. A thick client will provide users with more features, graphics and choices making the applications more customizable.
2. Unlike thin clients, thick clients do not rely on a central processing server because the processing is done locally on the user system, and the server is accessed primarily for storage purposes.
3. Thick clients often are not well-suited for public environments.

.NET

Information about .NET

The .NET Framework is a development and execution environment that allows different programming languages and libraries to work together seamlessly to create Windows-based applications that are easier to build, manage, deploy, and integrate with other networked systems.
Built on Web service standards, .NET enables both new and existing personal and business applications to connect with software and services across platforms, applications, and programming languages. These connections give users access to key information, whenever and wherever you need it.

SOAP

SOAP (Simple Object Access Protocol) is a way for a program running in one kind of operating system (such as Windows 2000) to communicate with a progam in the same or another kind of an operating system (such as Linux) by using the World Wide Web's Hypertext Transfer Protocol (HTTP)and its Extensible Markup Language (XML) as the mechanisms for information exchange.

An advantage of SOAP is that program calls are much more likely to get through firewall servers that screen out requests other than those for known applications (through the designated port mechanism). Since HTTP requests are usually allowed through firewalls, programs using SOAP to communicate can be sure that they can communicate with programs anywhere.

Web services have two types of uses.
Reusable application components
There are things different applications need very often.
Web services can offer application components like currency conversion, weather reports or even language translation as services.
Ideally, there will only be one type of each application component, and anyone can use it in their application.
Connect existing software
Web services help solve the interoperability problem by giving different applications a way to link their data.
Using Web services you can exchange data between different applications and different platforms.

Universal Description, Discovery and Integration (UDDI) is a platform-independent, XML-based registry for businesses worldwide to list themselves on the Internet. UDDI is an open industry initiative, sponsored by OASIS, enabling businesses to publish service listings and discover each other and define how the services or software applications interact over the Internet. A UDDI business registration consists of three components:
White Pages — address, contact, and known identifiers;
Yellow Pages — industrial categorizations based on standard taxonomies;
Green Pages — technical information about services exposed by the business.

What is a Web Application?
Simply, there are two kinds of Web sites, those that behave like magazines, places where you read stuff; and sites that behave like software, places where you go to do stuff.

Types of service provider

Application service provider (ASP)
Internet Service Provider (ISP)
Managed Service Provider (MSP)
Master Managed Service Provider (MMSP)
Telecommunications Service Provider (TSP)
Managed Internet Service Provider (MISP)

SOAP Disadvantages:
The SOAP specification contains no mention of security facilities.
SOAP 1.1 specification does not specify a default encoding for the message body. There is an encoding defined in the spec, but it is not required that you use this encoding to be compliant: Any custom encoding that you choose can be specified in the encodingStyle attribute of the message or of individual elements in the message.
Because SOAP deals with objects serialized to plain text and not with stringified remote object references (interoperable object references, IORs, as defined in CORBA), distributed garbage collection has no meaning.
SOAP clients do not hold any stateful references to remote objects.

Service provider

A service provider is an entity that provides services to other entities. Usually this refers to a business that provides subscription or web service to other businesses or individuals. Examples of these services include Internet access, Mobile phone operator, and web application hosting.

Why we use SOAP?

It is important for application development to allow Internet communication between programs. A better way to communicate between applications is over HTTP,because HTTP is supported by all Internet browsers and servers. SOAP provides a way to communicate between applications running on different operating systems, with different technologies and programming languages.

Universal Description Discovery And Integration(UDDI)

Universal Description Discovery And Integration

• It is a directory for storing information about web services.
• It is a directory of web service interfaces described by WSDL
• It communicates via SOAP
• It is built into the Microsoft .NET platform.

Difference between Web server and Application server?

Web server Application server

A Web server serves pages Application server provides
for viewing in a Web browser methods that client applications
can call

A Web server exclusively Whereas an application server
handles HTTP requests serves business logic to
application programs through any
number of protocols.

Where is SOAP used?

One of the most important uses of SOAP is to help enable XML Web Services. A web Service is an application provided as a service on the web. They are functional software components that can be accessed over the Internet. Web Services combines the best of component-based development and are based on Internet Standards that supports communication over the net.

SOAP

What is SOAP?
SOAP stands for Simple Object Access Protocol
SOAP is a communication protocol
SOAP is for communication between applications
SOAP is a format for sending messages
SOAP is designed to communicate via Internet
SOAP is platform independent
SOAP is language independent
SOAP is based on XML
SOAP is simple and extensible
SOAP allows you to get around firewalls
SOAP will be developed as a W3C standard

PROXY SERVER

Proxy servers sit between a client program typically a Web browser and an external server (typically another server on the Web) to filter requests, improve performance, and share connections.

FTP SERVER

FTP Servers :
One of the oldest of the Internet services, File Transfer Protocol makes it possible to move one or more files securely between computers while providing file security and organization as well as transfer control.

Types of servers

Types of servers are

• Web server
• Proxy server
• FTP server

Proxy Server:
A proxy server is a server which services the requests of its clients by forwarding requests to other servers. A client connects to the proxy server requesting some services such as file,connection,web page,or other resources available from a different server. A proxy server provides the resource by connecting to the specified server and requesting the service on behalf of the client. A proxy server that passes all request and replies unmodified is usually called a gateway.

WEB SERVER

Web Server:
A Web server serves static content to a web brower by loading a file from a disk and serving it across the network to a user's web brower. This entire exchange is mediated by the brower and servering talkingto each otherusing HTTP.

SOAP

Advantages:

• Using SOAP over HTTP allows for easier communication through proxies and firewalls than previous remote execution technology.
• SOAP is versatile enough to allow for the use of different transport protocols. The standard stacks use HTTP as a transport protocol, but other protocols are also usable (e.g. SMTP).
• SOAP is platform independent.
• SOAP is language independent.
• SOAP is simple and extensible.

"Internet Information Service" -- IIS

Internet Information Services (IIS) 6.0 is a powerful Web server that provides a highly reliable, manageable, and scalable Web application infrastructure for all versions of Windows Server 2003. IIS helps organizations increase Web site and application availability while lowering system administration costs. IIS 6.0 supports the Microsoft Dynamic Systems Initiative (DSI) with automated health monitoring, process isolation, and improved management capabilities. In IIS 6.0, an isolation mode that simulates the IIS 5.0 Web process model. Also called compatibility mode

Difference B/W Internet and World Wide Web

The Internet and the World Wide Web (WWW or Web) are not the same thing, though they are related. The Internet encompasses the Web, but it also encompasses other online protocols in addition to the Web. In basic terms, the difference between the Internet and the World Wide Web is that the former is a massive system of connected international networks, while the latter is one type of service available within that network
This is another difference between the Internet and the World Wide Web: the Internet supports many protocols, while the WWW is just one protocol of the many supported.

Web Server

Web Server is a computer that delivers (serves up) Web pages. Every Web server has an IP address and possibly a domain name. It is a computer program that is responsible for accepting HTTP requests from web clients, which are known as web browsers, and serving them HTTP responses along with optional data contents, which usually are web pages such as HTML documents and linked objects (images, etc.). For example, if you enter the URL http://www.blogger.com/index.html in your browser, this sends a request to the server whose domain name is "blogger.com". The server then fetches the page named "index.html" and sends it to your browser.

Simple Object Acess Protocol (SOAP)

SOAP is a lightweight protocol for exchange of information in a decentralized, distributed environment. It is an XML based protocol that consists of three parts:
1.An envelope that defines a framework for describing what is in a message and how to process it
2. A set of encoding rules for expressing instances of application-defined datatypes
3. A convention for representing remote procedure calls and responses.
SOAP can potentially be used in combination with a variety of other protocols

Web Services Description Language (WSDL)

The Web Services Description Language (WSDL) is an XML-based language used to describe the services a business offers and to provide a way for individuals and other businesses to access those services electronically. WSDL is the cornerstone of the Universal Description, Discovery, and Integration (UDDI) . UDDI is an XML-based registry for businesses worldwide, which enables businesses to list themselves and their services on the Internet. WSDL is the language used to do this.

Universal Description Discovery And Integration (UDDI)

UDDI (Universal Description, Discovery, and Integration) is an XML-based registry for businesses worldwide to list themselves on the Internet. Its ultimate goal is to streamline online transactions by enabling companies to find one another on the Web and make their systems interoperable for e-commerce. UDDI is often compared to a telephone book's white, yellow, and green pages. The project allows businesses to list themselves by name, product, location, or the Web services they offer.

Web Browser

A web browser is a piece of software used for viewing web pages. A Web browser is a software application that allows for the browsing of the web. (Examples: Internet Explorer, Netscape, FireFox). It is a program used to view, download, upload, surf or otherwise access documents (pages) on the World Wide Web. Browsers can be text-based meaning they do not show graphics or images but most however are text and graphical based.

Thick client

Thick clients, also called heavy clients, are full-featured computers that are connected to a network. Unlike thin clients, which lack hard drives and other features, thick clients are functional whether they are connected to a network or not.While a thick client is fully functional without a network connection, it is only a "client" when it is connected to a server. The server may provide the thick client with programs and files that are not stored on the local machine's hard drive. It is not uncommon for workplaces to provide thick clients to their employees. This enables them to access files on a local server or use the computers offline. When a thick client is disconnected from the network, it is often referred to as a workstation.

work groups

Definition of Work Groups: In computer networking, a workgroup is a collection of computers on a local area network (LAN) that share common resources and responsibilities. Workgroups provide easy sharing of files, printers and other network resources. Being a peer-to-peer (P2P) network design, each workgroup computer may both share and access resources if configured to do so. Workgroups are designed for small LANs in homes, schools, and small businesses.

The label "web services," as broadly applied, has two levels of meaning—one specific and one conceptual. Specifically, web services are a stack of emerging standards that describe a service-oriented, component-based application architecture. Conceptually, web services represent a model in which discrete tasks within e-business processes are distributed widely throughout a value net.

Web Services- Thin client

A thin client (sometimes also called a lean or slim client) is a client computer or client software in client-server architecture networks which depends primarily on the central server for processing activities, and mainly focuses on conveying input and output between the user and the remote server. Many thin client devices run only web browsers or remote desktop software, meaning that all significant processing occurs on the server.

Web services

Difference between Internet and WWW
Internet and WWW are not the same thing.
Internet-It is massive public broadcast.It is combn. of small digital subnetworks that share cables and computers.It provides structure.
WWW-It is single largest & most popular subnetworks on the Internet.It provides dynamic n/w

Welcome!

Dear girls,
This blog is intended to give an insight on Web Services. Through this blog we can share interesting facts,concepts and other titbits related to Web services, XML and related stuff. Apart from the syllabus, you can learn new things relevant which would be very useful. I have created this blog for your own good. Make the best use of it!

Note:

1. Contribution to the blog will carry marks
2. Avoid irrelevant posts
3. Do not post redundant information
4. Before posting any information just check whether if anybody else have posted the same

Rajitha