18: Session Software and open source OS organize and control hardware so flexible but predicable way o Manages the hardware and software resources, processor or memory o Provides way for applications to deal with the hardware without having to know all the details of the hardware o A combination of programs that coordinates the actions of a computer, including the peripheral devices and memory o Computing hardware physical components o Usually hardware specific o User interface The mechanism through which users interact with a computing device. The ui includes elements of the graphical user interface, such as windows, scroll bars, buttons, touch screen and such User interface Resource management File management Task management Utilities support services o OS designed to give programmers a common set of commands to consistently interact with the hardware o Firmwaresoftware stored that cannot be changed o Embedded systems included inside physical product o Platformproducts and goods that allow for development and integration of software and other good o Enterprise software applications that address the needs of multiple, simultaneous users in an organization o Software packagethird party peep o ERP CRM SCM BI o Database manage system DMBS or database system o Distributed computing computing where systems in different locations communicate and collaborate to complete a task o SERVER program that fulfils the requests of a client, hardware configured to support requests from other computers, o Client server system Client makes request, server tries fulfill request o Edi electronic data interchange, set of standards for exchanging information between computer applications (codes into 1 and 0's ) XML extensible markup language is better and newer
Algorithm o A set of instructions or steps (recipe) Defines the Environment Sequence Logical flow o Recipe Environmentingredients and equipment S and LF steps to convert ingredients into food o Algorithm Environment data and their location S and LF steps to convert data into information Programming languages C++IDE to write code integrated development environment o A language that allows a computer to understand an algorithm Word meaning, grammar, syntax o Similar to human language but more precise, structured, unambiguous o Machine language use binary code o Assembly language use symbolic coded instructions o High level languages use brief statements o Fourth generation languages use natural statements o Scripting languageuse inside applications and are interpreted inside applications Software o Conceptually the same as a program o A set of instructions that tells a computer what to do However in common usage o A program is a set of instructions for a specific task or purpose o Software is a collection of programs Multitasking o Ability to run two or more programs simultaneously on one computer Application software o Word processing software o Graphics Packages Software vs. software as a service o Software as service ASP application service provider "cloud computing " Stored offsite in central location o Cloud computing Run apps and store data remotely Software clouds ( SaaS) ASP or HSV online versions of applications, like quickbook over the internet Server farm provide backbone to SaaS Vendor provides applications over internet
Log in remotely and you're good to go, pay per use Maintenance, support, security provided by vendor Forgo large upfront costs Highly scalable Vendor must meet demand flux Economies of scale Verticle niches Risk o Goes not of business your hosed Hardware clouds e.g Amazon s3, ec2 Develops own software but wants someone else to run it for them Vendor provides the hardware platform for storage and computing and maintains it Pay based on usage, like storage Cloudbursting when you run out of your own shit, you use the cloud Virtualization type of software that allows a single computer to function as it were several different computers, each running its own operating system and software, underpins cloud computing Virtual desktop runs PC's software on another another machine and simply delivers output to remote device o Open Source Software linux is the biggest one Non-proprietary software which may or may ot be used commercial Typically licensed under an open source license Source code is generally made available Reverse engineering do not apply Cost cheaper with Reliability so many people seeing it, can catch bugs Security security flaws can become quicker to catcher Scalability can scale up cause can constantly rewrite the code o Proprietary vs. open source Source code is the code you input yourself into something, such as a programming language Object code is the ones and zeros that is converted from the source code after a complier Proprietary gives object code only, not source/ open source gives source code P- modifications are prohibited/ open s mods are permitted P- all upgrades and support down by licensor/ open s- licensee may do its own development or hire any third party for maintencance P- fee are for software licese, maintance and upgrades/p- fees if any are for integration, packaging, support and consulting
P-sublicensing is prohibited/ open s- sublicensing is permitted Session 19: Systems analysis and development SDLC-Systems development life cycle-requirement analysis, design, implementation, testing, evolution Software Development Methodology-framework that is used to structure, plan and controlling the process of developing an information system 2010-11 total us IT projects wasted 75-100 billion o 58 lost in dollar value, 42 in cost overruns o total project spending of 350 billion o 27% yay, 42 % challenged, 31 % have failed o late less than 14 % within 20% of scheule more than 46% more than 100 % late o over budget average project was 200% over budget less than 16 % come in on budget o under spec less than half have more than 75% of original features 30% never produce anything o Systems Development Life Cycle Planning or investigation Operational feasibility o Does it meet business operating requirements ? o If we need to change business procedures, can we ? Financial and economic feasibility o Cost benefit analysis Tangible and intangible o Return on investment Technical feasibility o Do we have the required technology( or can we get it)? o Is the technology reliable, scalable, and secure enough for our requirements? o Human factors and legal political Analysis or requirements What is required o Information outputs o Data acquisition Analysis of the current system Business process requirements Technological/ functional requirements o User interface, processing o Storage, control systems
What if users don't know what they want ? Design Detailed design o Outputs-sample reports, screen mockups o Inputs sample data entry screens/forms o Storage- Databases and files o Information processing o Controls and business process design o Goal: system specification Tools of the trade o Conceptual data modeling (entity-relationship diagrams) ER ERD Show what things we want to keep data about entities, what attributes we want to know about them, and how they relate together o Data flow diagrams Show where data comes from, where it is to go, what processing is required and where it is stored o DFD and ERDS are system analysis blueprints for a system Development Primary development activities o Develop IT infrastructure o Develop the database and programs Programming Acquisition of software and services Different software methodologies o Waterfall Slowly going downwards, from one process to the next One in SDLC o Rapid application development (RAD) Minimal planning in favor of rapid prototyping Write faster, and change better Much user involvement Planning and writing are the same step o Extreme programming Improve software quality and responsiveness to changing customer requirements
Frequent releases in short development cycles Breaks down into small phases Design methodology should follow project requirements o Mission critical water fall o General application development rad(spiral) o User centered development XP `Testing write the test conditions perform the system testing measuring business impact user feedback bug fixes business process changes problems and opportunities Implementation Write detailed user documentation (manual) Determine implementation method Conversion strategies o Parallel o Pilot (select users) o Phase in o Plunge Provide training to users User acceptance Maintenance Involves performing changes, corrections,additions and upgrades to ensure the system continues to meet the business goals Build a help desk to support the system users Perform system maintenance Provide an environment to support system change