Mainframe computer for efficient analysis by

mainframe computer for efficient analysis by marketing analysts and product supply chain managers.
The September 11, 2001, terrorist attacks and the current relatively high level of natural disasters such as Hurricane Katrina sparked many
companies to distribute their workers, operations, and systems much more widely, a reversal of the previous trend toward centralization.
The goal is to minimize the consequences of a catastrophic event at one location while ensuring uninterrupted systems availability.
Users can share data through file server computing, which allows authorized users to download entire files from certain computers
designated as file servers. After downloading data to a local computer, a user can analyze, manipulate, format, and display data from the file
(see Figure 6.8).
The file server sends the user the entire file that contains the data requested. The user can then analyze, manipulate, format,
and display the downloaded data with a program that runs on the user's personal computer.

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6-2c
Client/Server Systems
Figure 6.9. Client/Server Connection
Table 6.3. Advantages and Disadvantages of Client/Server Architecture
Advantages Disadvantages
Moving applications from mainframe
computers and terminal-to-host architecture
to client/server architecture can yield
significant savings in hardware and software
support costs.
Moving to client/server architecture
is a major two- to five-year
conversion process.
Minimizes traffic on the network because
only the data needed to satisfy a user query
is moved from the database to the client
device.
Controlling the client/server
environment to prevent unauthorized
use, invasion of privacy, and viruses
is difficult.
In client/server architecture, multiple computer platforms are dedicated to special functions such as database management, printing,
communications, and program execution. These platforms are called servers . Each server is accessible by all computers on the network.
Servers can be computers of all sizes; they store both application programs and data files and are equipped with operating system software
to manage the activities of the network. The server distributes programs and data to the other computers (clients) on the network as they
request them. An application server holds the programs and data files for a particular application, such as an inventory database. The client
or the server can do the processing.
A client is any computer (often a user's personal computer) that sends messages requesting services from the servers on the network. A
client can converse with many servers concurrently. For example, a user at a personal computer initiates a request to extract data that
resides in a database somewhere on the network. A data request server intercepts the request and determines on which database server the
data resides. The server then formats the user's request into a message that the database server will understand. When it receives the