Managing Information Systems In Organisations
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Managing Information Systems In Organisations
SYSTEMS DEVELOPMENT PROCESS
In recent years, there has been an abundance
of new technologies in the information systems field. These new technologies
have altered the very development process itself. Information systems
have gone from being a series of one level databases to three dimensional
reality, virtual reality, and multimedia systems. In the early days
of information systems, the demands were for data, with no real function
of artificial intelligence. However, as the 21st century approaches,
business has taken on an entirely different function, and the need for
individual information systems has grown immensely. This demand for
information technology is in all areas of business: corporations, law,
medicine, science and even small business. In addition, the worldwide
web and the Internet have added an additional factor of communications.
Most information systems in use today require at the very least, a measure
of Internet capability.
In order to understand the changes in
these development processes, the history of databases should be analyzed.
Database Management Systems actually began
in the 1950s, with what is known as the first generation, also known as
file systems on tape. The major task of any computer in those days
was to process data under the control of a program. This primarily
meant calculating, counting and simple tasks. Second generation databases,
file systems on disk, allowed use of computers in dialogue mode as well
as batch mode. The development of magnetic disks allowed for more
sophisticated file systems, making multiple access possible. These
first two generations of DBMS were characterized by the availability of
file systems only; strictly speaking these were the forerunners of database
systems, the foundations. An important component of these database
systems were the static association of certain data sets (files) with individual
programs that would concentrate on these. There were high redundancy problems
between files; inconsistencies when one program made changes that are not
made in all programs; inflexibility against changes in applications; low
productivity by programmers since program maintenance was expensive; and
the problem of adopting and maintaining standards for coding and data formats.
The third generation, pre-relational databases,
started in the 1960s and continued into the 1970s. This generation
is characterized by the introduction of a distinction between logical and
physical information, along with a parallel need to manage large collections
of data. Data models were used for the first time to describe physical
structures from a logical point of view. With this distinction between
the logical and physical information, value systems were developed which
could integrate all the data of a given application into one collection.
The fourth generation consisted of relational
databases and began in the 1980s, resulting in database systems that could
store data redundancy free under a central control and in a clear distinction
between physical and a logical data model. Systems based on relationship
modeling occurred during this period of time. The systems based on
relationship modeling are provided with a high degree of physical data
independence and the availability of powerful languages. Less of
the system is visible to the user, with changes taking place in the background.
A shift from record orientation to set orientation marks this fourth generation.
As of 1991, there was a fifth generation
predicted, post-relational, which we are currently experiencing, and perhaps
surpassing. Other applications can benefit from database technology.
The development of extensible systems, logic-oriented systems, and object-oriented
systems are part of this generation. R.G. Cattel speaks of the changes
seen in the last fifteen years:
"The past decade has seen major changes
in the computing industry. There has been a widespread move from
centralized computing to networked workstations on every desk. We
have seen an entirely new generation of software aimed at exploiting workstation
technology, particularly in engineering, scientific and office applications.
In database systems, there have been major
changes in products for business applications, including the widespread
acceptance of relational DBMSs. However, existing commercial DBMSs,
both small-scale and large-scale, have proven inadequate for applications
such as computer-aided design, software engineering, and office automation;
new research and development in database systems has been necessary.
The very nature of these new object oriented
databases has caused changes right down to the programming level.
As we near the end of this century, designers are now looking at databases
that can predict the side effects of medicines, eliminating the need for
human trial subjects. Other programs are being designed to put in
data for architecture to check building integrity. Car manufacturers
are able to input data and have three-dimensional models to experiment
with, regarding stress factors and damage.
With so much new technology erupting every
day, some needs have developed for a standardization of protocols and a
way to store all the data.
Mark Hammond (PC Week) talks about
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