How to Design Network?
In many situations, an application will have to
run on an existing architecture because that is what the organization is willing
or able to provide. In this case, the guidelines below can used, but they must
be modified to fit organizational constraints. Sometimes, however, the
architecture can be modified to provide the appearance of a new system. It is
very expensive to redesign large transactions processing systems, and some firms
have been updating the design of these systems by hiding the old system behind a
new PC interface.
In this section we suggest some guidelines for considering the interaction between hardware and software architecture and
systems design. The type of architecture will influence design. As systems
design we have very different choices depending on whether we plan to implement
on a LAN or mainframe with terminals.
Some basic guidelines are as follows:
- Start sizing architecture at the smallest and least expensive option. Can a suggested application be completed on a PC with packages? If there are multiple users accessing a central database, the answer is probably no. The same is true if there are too many simultaneous users. A PC will probably run Windows95 and above are Windows NT and will make use of a popular "suite" of office applications that include a spreadsheet, word processor, presentation graphics program, and database management system.
- If a standalone PC is not Adequate, can a system be developed using a LAN? The LAN can accommodate users who can share data files. The same software as above is appropriate but the server will probably run Windows NT. At some point, there may be too many users for the LAN, are more likely there will be too high a volume of activity for the server. It is also possible that the system must handle a large volume of transactions, in which case the LAN is not currently the nest alternative.
- A client-server architecture featuring workstations and minicomputer as the server is a cost-effective alternative for many applications as long as the system cam handle the processing load. The server may run NT or UNIX, while the clients run Windows95 and above. User applications may be developed using the PC database management package, or a DBMS like Oracle or Sybase.
- Mini computers have the capacity to handle a large number of transactions and large databases and can control large communications networks. You may program these systems in the language of a DBMS or in a language like C ++.
- Mainframes can handle large volumes of transactions and huge databases. They, too, excel at controlling large communications networks. If the mainframe applications exists already, then you will probably have little choice in the programming language and operating system. However, if the application is new, and you are using a new, large computer, you may be able to use UNIX as the operating system and C or a 4GL as an applications development language.
- If users need local processing power and discretionary use of computers, a mixed network including mainframes and PCs is likely. This configuration is also popular when the organization has a large number of old computers and applications; networking them together provides users with the features they need and widespread data access.
- For providing links with customers, suppliers and others, consider the option of using the Internet and World Wide Web.
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