The Internet Phenomenon - Secure Java: For Web Application Development - page 5

mathematical subroutines and subroutines for functionalities such as sorting, indexing, and so on.
Most of the mainframe systems during this era could do a simple sequential batch processing and
time-shared processing of multiple jobs of these applications, but they were not capable of doing
advanced parallel processing in terms of either hardware or software processing ability.
1.1.1.2 Mainframe Systems Today
Despite the sea of changes in the evolution of computers and information technology space, main-
frame systems exist even today. Many major enterprises around the world still use mainframe sys-
tems as a part of their core business operations. Many of the enterprises have retained mainframe
systems and software as a part of their core business computational systems to strike the right
chord between using the future trends and technologies and existing reliable and “irreplaceable
archaic systems.” he new-age mainframe systems are now capable of supporting sophisticated
and smart terminals and performing parallel processing on both the hardware front and the soft-
ware front. On the software front, these systems are capable of supporting applications that can
perform a huge number of complex business and scientiic operations reliably and securely. Most
of these newer mainframes can now be integrated with the evolving newer systems and architec-
tures, as demanded by the ever-changing dynamic business needs of the enterprises.
1.1.2 Client/Server Era
he arrival of minicomputers (referred to as minis ) and workstations in the initial part of the
1970s started changing the scenario in the business and the scientiic world of computation. hese
systems were afordable to even SMBs and educational and research institutions around the world
and therefore led to the proliferation of such systems across the world. he proliferation of these
systems along with the possibility of networking these systems—clubbed with the emergence of
computer communication protocols, such as IPX/SPX from Novell Netware, Apple's AppleTalk
and Open Systems Interconnect (or OSI), and TCP/IP—led to the era popularly known as the
client/server era. he nature and functionality of the server and client are described briely in the
following sections.
1.1.2.1 Server
In the client/server environment, a server program receives requests from one or more client pro-
grams, executes the logic for data retrieval and database updates, and manages data integrity and
dispatch responses to client requests. Occasionally, this server program also executes business
logic. he server process essentially acts as an engine that manages shared resources such as iles,
databases, and printers on the server-side environment.
An enterprise may require many server systems to meet diferent functionalities of the business
requirements. Web servers, ile servers, database servers, print servers, FTP servers, and so on, are
some of the commonly used servers in the enterprise—usually in a local area network (LAN), a
wide area network (WAN), or a metropolitan area network (MAN) environment.
1.1.2.2 Client
he client is a process that sends a message to a server process, requesting that the server per-
form a speciic task (or a set of tasks) and fetch data/information. Client processes are designed