Client/Server Technology

Infsy 540

Dr. Ocker

Past

centralized business computing and centralized model of organizational computing -- mainframes

high degree of control for systems managers

end-users not very involved barriers to information access - sharing

not the norm

Now

End-user computing is here to stay

less control for systems managers sharing of data is the norm client-server computing is replacing the

mainframe

various meanings of client/server technology

One meaning: formal systems architecture describing technologies that

cooperate together on a computer network users operate PCs (clients) that connect to central computers

(servers) over a computer network both computers cooperate to spilt the work of performing various

tasks

set of management strategies for creating systems that improve org’al effectiveness

• strategies for distributing computing resources within an org. to support interpersonal communication, organizational coordination, and business collaboration

various meanings of client/server technology Another meaning: set of management strategies for creating

systems that improve org’al effectiveness strategies for distributing computing

resources within an org. to support interpersonal communication, organizational coordination, and business collaboration

Client/Server Model

enterprise networking - an arrangement of the org’s HW, SW, telecommunications, and data resources to put more computing power on the desktop and create a company-wide network linking smaller networks

client/server model of computing

primary way of delivering computing power to the desktop

computing, data and processing power are distributed throughout the organization rather than being centrally located

client/server model of computing

emphasizes the user’s interaction with the data

splits processing between clients and servers

client

user point of entry into a network normally a desktop computer,

workstation, or laptop user generally interacts directly only

with the client portion of an application

server

satisfies some or all of a user’s request for data

also runs the application software can be a mainframe or another desktop

computer servers store and process shared data

Infrastructure

c/s computing enables restructuring of information flow by distributing computing resources and allowing access to information

hw and sw must function as a series of pathways/highways

Core capabilities of c/s computing users use desktop computers to do

much of their work locally when they need to access shared

information or to use resources of another (more powerful) machine, they connect their desktop (client) machine to the remote machine (server) using a network

Clients

provide user interface - GUI - graphical user interface

run stand alone applications (e.g. word processing) - these applications use entirely local resources for both processing and data storage

run the client side of client-server applications

Servers

shared resources that are accessible over the network;used by clients

combine both hw and sw clients contact servers with requests servers process the request and return the

results to the clients many clients use the server; end-users can

share information by accessing a common database (stored on the client)

Networking

key to c/s communications clients and servers pass information

back and forth via a network

Distributing the work

fig. - shows 5 different ways that components of an application can be partitioned between the client and the server

applications must be written as two or more separate software components that run on different machines but that appear to operate as a single application

Payroll example

client tasks could include– input data– submit data queries to the server– display results on screen or printer

server task could include– fetch the entered data– process the payroll– control access

Business benefits of C/S computing enables new approaches to business

computing by restructuring flow of communication and information within orgs.

improved communication, coordination, and collaboration --> Groupware– email, computer conferencing,

electronic calendars, shared databases

Business benefits of C/S computing distributed data stores consist of different

servers that collect and organize information corporate data warehouses

– can be located centrally on a mainframe;– receive data extracts periodically from operational

systems (e.g. TPS); – serves as a repository for shared information; – information can be distributed on various

machines (servers)

Some Limitations

more difficult to write SW that divides processing among clients and servers

server can get overloaded when too many users simultaneously want service

Major influences that cause firms to shift to Client/Server technically and economically feasible to

transfer computing power to desktop -- declining prices, good telecomm. capabilities

knowledge-based workers create and work with information ; require easy access to information - C/S systems enhance productivity by placing information where users are

Major influences that cause firms to shift to Client/Server communication is faster, easier and less

costly with C/S technology -- important in global economy

flatter orgs. need more decentralized from of computing

support team work through networking

Major influences that cause firms to shift to Client/Server offers flexibility to orgs. who need to

change rapidly - easy to connect new clients (e.g. team members); can easily upgrade power of server without interrupting service

cost savings - supposedly cheaper

key principles for managers in transition to c/s computing

to achieve value from the (costly) investment in c/s computing, need to commit to process redesign

two different levels of investment - infrastructure and applications

key principles for managers in transition to c/s computing

need to make long-term investments in backbone communications networks; plan for ever-increasing bandwidth

building the enabling infrastructure is a strategic effort

building distributed applications is a tactical effort

key principles for managers in transition to c/s computing

individuals and workgroups need to exploit the potential networked infrastructure enables people to

work together and share information in a variety of ways