system architecture
the translation of the logical design of an information system into a physical structure that includes hardware, software, network support, processing methods, and security.
Before making a decision, the analyst must consider several issues that will affect the architecture choice:
1. corporate organization and culture.
2. enterprise resource planning.
3. initial and total cost of ownership.
4. scalability.
5. Web integration.
6. legacy system interface requirements.
7. processing options.
8. security issues.
9. corporate portals.
enterprise resource planning
the establishment of a company-wide strategy for using information technology that includes a specific architecture, standards for data, processing, network, and user interface design.
platform
a specific hardware and software environment that ensures connectivity and easy integration of future systems, including in-house software and commercial packages.
supply chain management
the extension of enterprise resource planning systems to suppliers and customers.
A total cost of ownership should include the following questions:
1. If in-house development was selected as the best alternative initially, then is it still the best choice?
2. Is the necessary technical expertise available, and does the original cost estimate appear realistic?
3. If a specific package was chosen initi
node
a physical device, wired or wireless, that can send, receive, or manage network data.
scalability (or extensibility)
a system's ability to expand, change, or downsize easily to meet the changing needs of a business enterprise.
applications
programs that handle the input, manage the processing logic, and provide the required output.
Web-centric
following Internet design protocols and enabling a company to integrate the new application into its e-commerce strategy.
legacy systems
older systems that use outdated technology but are still functional.
portal
an entrance to a multifunction website.
corporate portal
a portal that can provide access for customers, employees, suppliers, and the public.
Every business information system must carry out three main functions:
1. manage applications that perform the processing logic.
2. handle data storage and access.
3. provide an interface that allows users to interact with the system.
server
a computer that supplies data, processing services, or other support to one or more computers, called clients.
mainframe architecture
a system design where the server performs all the processing
local area network
a network that allows sharing of data and hardware resources.
wide area network
a network that spans long distances and can connect with local area networks that are continents apart.
distributed systems
company-wide systems that connect one or more local area networks or wide area networks.
client/server architecture
systems that divide processing between one or more networked clients and a central server.
legacy data
data that's difficult to access and transport to a client/server environment.
fat (or thick) client
a design that locates all or most of the application processing logic at the client.
thin client
a design that locates all or most of the processing logic at the server.
two-tier
a design in which the user interface resides on the client, all data resides on the server, and the application logic can run either on the server or on the client, or be divided between the client and the server.
three-tier
a design in which the user interface runs on the client and the data are stored on the server, just as with a two-tier design.
middleware
special software that enables the tiers to communicate and pass data back and forth.
knee of the curve
the mark of a sharp decline in the system's speed and efficiency.
distributed database management system
a data storage that can reduce network traffic.
cloud computing
the cloud symbol that is often used to represent the Internet.
scaling on demand
matching resources to needs at any given time.
bandwidth
the amount of data that can be transferred in a fixed time period.
wiki
a Web-based repository of information that anyone can access, contribute to, or modify.
Internet operating system
an overall environment in which new layers of information are added.
An in-house strategy can provide valuable benefits, including:
1. a unique website, with a look and feel consistent with the company's other marketing efforts.
2. complete control over the organization of the site, number of pages, and size of the files.
3. a scalable structure to handle increases in sales and produc
online system
a system that handles transactions when and where they occur and provides output directly to users.
Online processing systems have four typical characteristics:
1. The system processes transactions completely when and where they occur.
2. Users interact directly with the information system.
3. Users can access data randomly.
4. The information system must be available whenever necessary to support business functi
The main advantages of batch methods are that:
1. tasks can be planned and run on a predetermined schedule, without user involvement.
2. batch programs that require major network resources can run at times when costs, and impact on other traffic, will be lowest.
3. a batch method is well-suited to add
Open Systems Interconnection
a model that describes how data moves from an application on one computer to an application on another networked computers.
network topology
the way that a network is configured.
physical topology
a description of the actual network cabling and connections.
logical topology
the way that the components interact.
hierarchical network
a network in which one or more powerful servers control the entire network.
bus network
a network in which a single communication path connects the central server and departmental servers, workstations, and peripheral devices.
ring network
a network that resembles a circle where the data flows in only one direction from one device to the next.
star network
a network with a central networking device called a SWITCH, which manages the network and acts as a communications conduit for all network traffic.
hub
a device used to connect start networks that is now replaced by the switch.
data frames
network traffic that the hub broadcasts to all connected devices.
mesh network
a network on which a message cna travel on more than one path.
router
a device that connects network segments, determines the most efficient data path, and guides the flow of data.
gateway
a connection between a any network topology and a larger, dissimilar network such as the Internet.
proxy server
a device that provides Internet connectivity for internal local area network users.
wireless local area network
a network that is relatively inexpensive to install and is well-suited to workgroups and users who are not anchored to a specific desk or location.
Institute of Electrical and Electronics Engineers
the institute that came up with the 802.11 standards, including the 802.11n version which uses multiple input/multiple output technology to boost performance.
multipath desgn
multiple data paths that increase bandwidth and range.
Basic Service Set (or infrastructure mode)
a configuration in which a central wireless device called an ACCESS POINT or WIRELESS ACCESS POINT is used to serve all wireless clients.
Extended Service Set
a set made up of two or more Basic Service Set networks.
roaming
automatically allowing the client to associate with the stronger access point, allowing for undisputed service.
WiMAX
broadband wireless communications protocols for metropolitan area networks.
system design specification
a document that presents the complete design for the new information system, along with detailed costs, staffing, and scheduling for completing the next systems development life cycle phase: IMPLEMENTATION!
A typical system design specification typically includes the following sections:
1. management summary.
2. system components.
3. system environment.
4. implementation requirements.
5. time and cost estimates.
6. additional material.