FREE online courses on Information Technology - Chapter 2 FRAMEWORKS FOR IT
- THE BASICS OF INFORMATION SYSTEMS
Three different kinds of information systems are:
(a)
Transaction system
(b)
Decision system
(c)
Communications system
A transactions
processing system, processes input provided by a user, such as the fact that
a client purchased a certain number of shares of AT&T. The input is first edited
for errors and corrected, if necessary. For example, if the person doing the
input typed ATR and there is no such stock, the system would ask for the data to
be typed again. The input then becomes immediate output (a purchase confirmation
for the customer) and is used to modify the database of stock records in the
system. Input can also be used to request the retrieval of information stored in
the system, such as the customer's entire stock portfolio.
Files containing data are a major component of the
information system. The files correspond to the information kept in folders,
file cabinets, or notebooks in a manual information system. Files are a part of
the organization's database. Information may be retrieved from a file, or the
file contents may be altered by modifying, adding, or deleting data in the file.
We are also interested in some type of output from a system, which may be a
short response to a request for information from a file or the result of
elaborate computations. Output is produced in any of a number of different
formats and modes of presentation, such as a printed report, a display on a
screen, or a verbal response.
In a decision-oriented
system, the decision maker uses a workstation to run a decision support
system. The DSS software allows the user to retrieve data from the database. The
same software might contain a model management subsystem allowing the user to
apply different kinds of models to
analyzing the data. The system also provides different modes for presenting the
results of analyses to the decision maker.
In a
communications-oriented system, here there are two users who communicate
through a central computer, possibly one that is owned and operated by a common
carrier who provides electronic mail services. Each user operates a workstation
and sends messages to a file that contains electronic mailboxes for all
subscribers on the system. When user 2 connects with the central computer from
his or her workstation, there is a message notifying user 2 that there is new
e-mail waiting to be read. User 2 can read the mail, forward it to someone else,
and/or send a reply to user 1.
