MBA 211 - Chapter 5

Server

A computer or computer program that manages access to a centralized resource or service in a network.

Client

A computer that requests data stored on a server.

Web Server

A computer that runs special software to serve up Web content by responding to requests.

Minicomputer

A midsize, multi-user computer; more powerful than a workstation or personal computer but less powerful than a mainframe computer.

N-tier (multi-tiered) computing

A multi-tier application is any application developed and distributed among more than one layer. It logically separates the different application-specific, operational layers. The number of layers varies by business and application requirements, but three-tier is the most commonly used architecture. Any application that depends on or uses a middleware application is known as a multi-tier application. A multi-tier application is also known as a multitiered application or n-tier application.

Web browser (browser)

A program that interprets and displays Web pages and enables you to view and interact with a Web page.

Legacy systems

A system that has been in existence for a long time and that continues to be used to avoid the high cost of replacing or redesigning it.

Total Cost of Ownership (TCO)

All of the costs associated with the design, development, testing, implementation, documentation, training and maintenance of a software system.

Operating System Software

Controls the application software and manages how the hardware devices work together. Examples include Windows, Unix, & Linux.

Evolution of IT infrastructure

General-purpose mainframe and minicomputer era: 1959 to present. - 1958: IBM first mainframes introduced. - 1965: Less expensive DEC minicomputers introduced. Personal computer era: 1981 to present. - 1981: Introduction of IBM PC. - Proliferation in 80s, 90s resulted in growth of personal software. Client/server era: 1983 to present. - Desktop clients networked to servers, with processing work split between clients and servers. - Network may be two-tiered or multitiered (N-tiered). - Various types of servers (network, application, Web). Enterprise computing era: 1992 to present - Move toward integrating disparate networks, applications using Internet standards and enterprise applications. Cloud and mobile computing: 2000 to present - Cloud computing: computing power and software applications supplied over the Internet or other network. - Fastest growing form of computing.

Cloud computing consists of three different types of services:

Infrastructure as a service (IaaS): Customers use processing, storage, networking, and other computing resources from cloud service providers to run their information systems. For example, Amazon uses the spare capacity of its IT infrastructure to provide a broadly based cloud environment selling IT infrastructure services. These include its Simple Storage Service (S3) for storing customers' data and its Elastic Compute Cloud (EC2) service for running their applications. Users pay only for the amount of computing and storage capacity they actually use. (See the Interactive Session on Organizations). Figure 5.10 shows the range of services Amazon Web Services offers. Software as a service (SaaS): Customers use software hosted by the vendor on the vendor's cloud infrastructure and delivered as a service over a network. Leading software as a service (SaaS) examples are Google Apps, which provides common business applications online, and Salesforce.com, which leases customer relationship management and related software services over the Internet. Both charge users an annual subscription fee, although Google Apps has a pared-down free version. Users access these applications from a web browser, and the data and software are maintained on the providers' remote servers. Platform as a service (PaaS): Customers use infrastructure and programming tools supported by the cloud service provider to develop their own applications. For example, IBM offers a Bluemix service for software development and testing on the IBM cloud. Another example is Salesforce.com's Force.com, which allows developers to build applications that are hosted on its servers as a service.

Cloud Computing

Model of computing in which computer processing, storage, software, and other services are provided as a shared pool of virtualized resources over a network, primarily the Internet.

Web services

Platform-independent information exchange systems that use the Internet to allow interaction between firms.

Moore's Law

Refers to the computer chip performance per dollar doubles every 18 months

Virtualization

Running multiple systems simultaneously on one physical computer

SaaS (Software as a Service)

Services for delivering and providing access to software remotely as a web-based service

Service-oriented architecture (SOA)

Software architecture of a firm built on a collection of software programs that communicate with each other to perform assigned tasks to create a working software application

Application Server

Software that houses and serves business logic for use (and reuse) by multiple applications.

Software-defined Storage (SDS)

Software to manage provisioning and management of data storage independent of the underlying hardware.

Nanotechnology

Technology that builds structures and processes based on the manipulation of individual atoms and molecules.

Cloud Computing Characteristics

The U.S. National Institute of Standards and Technology (NIST) defines cloud computing as having the following essential characteristics: On-demand self-service: Consumers can obtain computing capabilities such as server time or network storage as needed automatically on their own. Ubiquitous network access: Cloud resources can be accessed using standard network and Internet devices, including mobile platforms. Location-independent resource pooling: Computing resources are pooled to serve multiple users, with different virtual resources dynamically assigned according to user demand. The user generally does not know where the computing resources are located. Rapid elasticity: Computing resources can be rapidly provisioned, increased, or decreased to meet changing user demand. Measured service: Charges for cloud resources are based on amount of resources actually used.

Open Source Software (OSS)

The programs distributed and licensed so that the source code making up the program is freely available to anyone who wants to examine, utilize, or improve upon it.

Information Technology (IT) Infrastructure

The shared technology resources that provide the platform for the firm's specific information system applications

Two-tiered client/server architecture

The simplest client/server network consists of a client computer networked to a server computer, with processing split between the two types of machines.

Metcalfe's Law

The value of a network is equal to the square of the number of users connected to it

HTML (Hypertext Markup Language)

The written code that creates Web pages and links; a language all computers can read

Legacy systems are still in use today because:

They are too expensive to redesign.

Mashup

a website or web application that uses content from more than one source to create a completely new product or service Book's definition: Composite software applications that depend on high-speed networks, universal communication standards, and open source code.

Technology Standards

specifications that establish the compatibility of products and the ability to communicate in a network