Information Systems: Concepts, Development, and Components - Prof. Jean M. Lacoste, Study notes of Accounting

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Chapter 1: Information Systems Basic Concepts What is an information system?  System: a set of components that interact to achieve a purpose  Information system: set of components that interact to produce information, should be beneficial to the company not just for popularity, must be constructed  Information Technology: products and standards used to produce information, IT drives the development of IS  You can buy IT but not IS  Five component framework: o Computer hardware-physical component (monitor, keyboard) o Software- instructions that tell the hardware what to do (OS, programs) o Data- raw facts o Procedures- instructions that tell the people what to do (typing) o People- who developed the computer or who uses it (teacher, students)  Automation: instead of people doing it, software should be made so that computers can do it. Shifting work from one person to another is not automation. IS Functions (IPO Model) All computers perform these basic functions  Input- data into computer  Processing- transforming the data  Output- sending data into the environment which can be either another system/compute or person.  Storage- where the data is at rest, what we do with it when it is not being used Example: Hokie Spa Password Change  Input: gathers PID, current password and new password from the human  Processing: comparing the username and password to the correct username and password  Output: New password successful message  Storage: of the PID and password Business Information Systems  Can be categorized into: o Operational- focus on input (sorting) o Collaboration-interaction o Managerial-focus on output Operational Information Systems  Used by lower level employees for input or data collection  Simple, minimal calculations  Transaction Processing Systems (TPS): gather data about individual, routine transactions like clocking in, requires few calculations, focus is on capturing data Example: Interlibrary Loan  Process Control Systems (PCS): input focused, constant monitoring, records data at predetermined points in the process and compares it to preset boundaries, system is turned on and stays on. Example: Antilock Brake System constantly monitors how fast each wheel is spinning, connected to another IS Collaboration Information Systems  Used by all levels of employees, supports the efforts of groups  Communication Systems: oral and written exchange, quick and easy exchange of data, all components are optimized, transfer of data among workgroup members. Example: texting, facebook chat  Content Management Systems: keeping track of team documents and making them readily available. Allows multiple users to add, change, and delete content from various documents. Example: Google Docs  Workflow Control: support the activities teams must engage in, focus on shared scheduling. Example: Microsoft SharePoint Managerial Information Systems  Used by middle and upper level managers for decision making  Output and the processes necessary to produce the output  Management Information Systems: most common, used for small daily decisions, simple processing and calculations, routine reports periodically, data changes but format stays the same. Example: daily sales report  Executive Information Systems: customized reports generated from sample calculations, may be generated only once specifically for whatever output you need, bigger decision making. Example: Ebay customize homepage.  Decisions Support Systems: outputs customized and produced on demand, complex calculations with calculus and higher math in them. Example: Pasture land management system.  Central Processing Unit: a processing device, the brain of the computer. Selects instructions, processes them, performs math and comparisons, and sores results of operations, storing data  Dual processor: Computer with two CPUs  Quad processor: Computer with four CPUs  Main memory: circuitry for storing data and instructions that are read by the CPU. Also known as the RAM.  Special Function Cards: electronic components on thin fiberglass backing that can be added to the computer  Output hardware: video displays, printers, audio speakers, overhead projectors,  Storage hardware: saves data and programs, CDs and DVDs Computer Data  Binary digits: bits used to represent data, either a zero or a one, easy to represent  All computer data are represented by bits which are grouped into 8-bit chunks called bytes. How a Computer Works  Computer transfers the program or data from disk to main memory  Moves the instruction from main memory into the CPU via the data channel  CPU has a small amount of fast memory called a cache where it keeps frequently used instructions  Main memory has the program instructions for Microsoft Excel, Adobe, and Internet and a block of data and instructions for the operating system  Memory swapping to keep the active memory limited.  Why a manager cares: you need to know how much memory different types of employees need. Employees that only do simple word processing don’t need a fast computer  Volatile: contents are lost when the power is off (cache and main memory)  Nonvolatile: contents survive when power is off (optical disks) What do Business Professionals need to Know about software?  Managers need to know essential terminology  Every computer has an operating system: a program that controls the computers resources. Read and write data, allocate main memory, perform memory swapping, start and stop programs, facilitate backup and recovery. It creates and manages the user interface  Applications programs: in addition to the OS  A particular version of an operating system is written for a particular type of hardware Four Major Operating Systems  Windows: most important systems for business users. On 85% of the worlds desktop. Windows 7, Windows XP, Windows Server. Runs on intel.  Mac OS: developed by apple. Used primarily by graphic artists and workers in the arts community. Led the way in developing easy to use operating systems  Unix: developed in the 70s used in scientific and engineering communities, difficult to use, not for the business user  Linux: version of Unix developed by the open sources community (programmers) used mostly for servers  What do they do? o Memory management o Allows you to make changes to how the device works, communicate with the computer o Application interface between hardware and software What is ASCII?  Character coding scheme  Most coding systems are pretty much the same  Different from binary  Binary: 00001101 (13) ASCII: 00110001 00110011 (13)  ASCII takes up more space  Bit: a single digit (1 or 0)  Byte: group of 8 bits Own Versus License  License: right to use a certain number of copies of that program subject to limits on the vendors liability.  Large organizations negotiate a site license: a flat fee payment for the right to install the product on all of that company’s computers, Linux is not sold. Cloud Computing and Virtualization  Cloud computing: a form of hardware/ software leasing in which organizations obtain server resources from vendors that specialize in server processing. Customers pay only for resources used. A form of CPU-cycle inventory consolidation.  Virtualization: the process whereby multiple operating systems share the same hardware. Due to virtualization it is easy for cloud vendors to reconfigure servers to support changes in the workload Applications  Application software: performs a service or function  Horizontal-market application: provides capabilities common across al organizations and industries. Word processors, spreadsheets, presentations. No customization necessary, bought off of the shelf.  Vertical market application: serve the needs of a specific industry. Dentists’ scheduling programs. Can be altered and customized.  One-of-a-kind Application: developed for a specific, unique need  Off the shelf, Off the shelf with alterations, custom developed  Custom development is difficult and risky. Managing software development is difficult, very expensive, has to be adapted as more technology is developed. Firmware  Computer software installed into devices such as printers, print servers, and various communication devices.  Installed into special read only memory of the printer or other device  Program becomes part of the devices memory  Can be changed or upgraded Storage  Primary storage: volatile (goes away when the computer is shut off)  Secondary storage: permanent, larger, cheap (CDs) Motherboard  Infrastructure, takes power to all the other parts  Control unit: organizes components and sends instructions (traffic cop)  Cache and Registers: preferences referenced most often  ROM: primary memory but is permanent  Arithmetic Logic Unit: does all the math RAM  Restarting your computer clears the RAM, the main memory can fill all the way up and then the computer starts to gurgle and such. 3 Types of Software  Application software: office, browser, email, games  System Software: operating system, programming languages, CASE tools (draw blue prints, software for the computer to run  Firmware: device specific, inseparable Chapter 8:  Consider requirements for team and personnel Approve Requirements  Users should review and approve requirements before the project continues  It is better to change a requirement now rather than later How are the Five Components Designed? Hardware:  determine specifications and the source, purchase or lease it Software:  depends on the source of programs  determine what to acquire off the shelf and if it needs to be altered  If a custom program is needed the team produces design documentation for the new program Database:  Convert the data model to a database design Procedure:  Organize procedures for both users and operations personnel  For normal, backup, and failure recovery options  Systems analysts and key users design procedures Job Descriptions:  Its better to just extend the project deadline than try to hire more programmers How is an Information System Implemented?  Build, test, and convert the users to the new system  Obtain, install, test hardware  License and install off the shelf programs  Construct a database and fill it with data  Document, review, and test procedures System Testing  Test plan: consists of sequences of actions that users will take when using the new system, not just the normal actions but incorrect ones too.  Product Quality Assurance (PQA): testing with the advice and assistance of users  Beta testing: process of allowing future systems to try out the new system on their own System Conversion  Converting business activity from the old system to the new.  Pilot installation: implement the entire system on a limited portion of the business. If the system fails, it is contained within a boundary, reduces the exposure of the business.  Phased installation: installed in phases across the organization. Little pieces at a time. Some systems are to intertwined to be installed in phases.  Parallel installation: new system runs along with the old one until the new system is tested and fully operational. Expensive because you have to pay for both systems, very slow but provides good feedback.  Plunge installation: or direct installation. The old system is shut off and the new one is turned on. If the new system fails, you’re screwed. Very risky. What are the Tasks for System Maintenance?  Fix or adapt the system  There has to be a means for tracking failures and requests for enhancements  IS personnel prioritize system problems according to their severity.  Patch: fixes for high- priority failures are grouped into these and can be applied to all copies of a given product  Service Packs: fixes of lower priority problems