Information Systems Reengineering, Integration and Normalization - Information Systems Reengineering, Integration and Normalization - page 1

Chapter 1
Information Systems Reengineering, Integration
and Normalization

1.1 History of Information Systems

The primary goal of electronic data processing (EDP) in the 1960s and 1970s was
the automation of existing business operations in organizations. However, except
for the quick availability of more accurate management reporting information, such
operations were automated without fundamental changes. During these two de-
cades, data was stored in flat file formats that could be classified into two different
forms, namely batch files and online files.

1.1.1 Batch Files

Computer applications were initially developed for batch processing, where pro-
grams would process a specific type of data regularly. Each suite of programs was
associated with its own data files. Generally, magnetic tapes were used to hold these
files. The sequential nature of the storage medium required the reading and writing
of the entire file to reflect any changes to the data stored. Sequential access was
simple and effective for batch applications. As more applications were computer-
ized, it became obvious that some of the required data already existed in the data
files used by other computer applications.

1.1.2 Online Files

Many batch applications were redesigned for online processing, with the advent of
direct access storage devices (DASD) and advances in telecommunications. The
random sequence of data input by online applications requires a monitor that ex-
amines each input transaction, and then passes its transaction to the appropriate
computer program.