Application Understanding

ByCh. TanujaNagarjun*APPLICATION UNDERSTANDING

Software is a set of programs that are designed to instruct a system to perform well defined task.Types of software:System SoftwareApplication SoftwareSystem software: Collection of programs designed to operate, control and extend the processing capabilities of the computer itself. Ex: Operating System, Device drivers and Utility software like Anti-Virus, maintenance tools.

*SOFTWARE

Application software are the set of programs that are designed to perform a particular task to satisfy the user needs.Apps made the tasks simple, fast, cost effective and secure.Examples: Word ProcessorsMedia PlayersComputer GamesEmulatorsWeb Browser, etc.,

*APPLICATION SOFTWARE

Desktop Applications: These are standalone applications which are installed in individual computers and utilizes resources like CPU, GPU, Memory etc., of its host computer to run.These are platform dependent.They must be manually installed and updated in each computer.Coded in Programming languages like J2SE, C++ using QT, Python, etc.. *Types of Applications

Web Applications: These are applications that gets executed in web server and get rendered in web browser of a client.These are mostly platform independent.Need not update and can maintain without distributing, installing and updating software on all client computers.Doesnt utilizes much of the resources of client computers since business logic gets executed on server computer.More secure and easy to use than desktop applications.Examples: All the websites like www.facebook.com, www.coursera.com, etc.These are coded in HTML, CSS, JavaScript, AJAX, JSP, EJB, PHP, Python, .NET, etc.*Types of Applications

Mobile Applications: These are the software designed to run on smart phones, tablet computers and other mobile devices.These are strictly platform dependent.These are coded in Android (Dalvik JVM), Symbian C++, QT, C, J2ME.Various platforms in mobile devices are Android, iOS, Windows Phone, Symbian, MeeGo, PalmOS, etc.*Types of Applications

An applications architecture describes the structure and behaviour of applications used.Layer: Logical way of organizing code.Types: Presentation Layer, Business Layer and Data Layer.Tier: Specifies where code runs physically. Tiers are physical deployment of LayersExamples: Client computer (Presentation Layer is deployed) Web Server (Business Layer is deployed) Database Server (Data Layer is deployed)*Application Architecture

All the 3 Layers i.e. Presentation, Business and Data layers are present in one system (client).All the processing is done in client system itself.Examples: MS Word, Autodesk Maya, Photoshop, etc.Advantages:No network connection is required.Easy to optimize performance.Disadvantages:Difficult to maintain or modify.Platform dependent.

*1- Tier ArchitectureUserPresentation LayerBusiness/Logic LayerData LayerClient System

Client and database are on different systems i.e. Presentation and Business layers are present in client system and data layer is present in server system.Examples: WINSCP, Remote Desktop access, DLNA Server, Torrents etc.Advantages:Portability.Secured Data.Disadvantages:Caching of data

*2- Tier ArchitectureUserPresentation LayerBusiness/Logic LayerData LayerClient SystemData ServerNetwork connection

It is a client-server architecture in which presentation, business and data layers are separated.Presentation Layer: This displays information and provide UI for user. Web Browser is used for rendering information and UI.(HTML, CSS, JavaScript)Business Layer: Acts as middle tier between user and data. Executes business logic using webserver. (JSP, EJB, PHP, .NET)Data Layer: Consists of database management systems. Here information is stored, retrieved and maintained

*3- Tier ArchitectureUserPresentation LayerBusiness/Logic LayerData LayerClient System(Web Browser)Data ServerWeb ServerClients Web BrowsersLike Chrome, IEWebservers like Tomcat, WebsphereDB Management Systems Like Oracle, MySQL, DB2

Advantages:Increased PerformanceReusabilitySecureLayer independentEasy to updateDisadvantages:Performance depends on network bandwidthComplex structure

*3- Tier Architecture

Acronym for Create, Read, Update, Delete.4 major functions implemented in Relational Database Applications.They map to standard SQLCreate -> INSERT Read -> SELECTUpdate -> UPDATEDelete -> DELETE*CRUD

*EXAMPLESDesktop and 1-Tier App:Mobile App:2-Tier App:Web and 3-Tier App:

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