FREE online courses on Information Technology - Chapter 2 FRAMEWORKS FOR IT
- USING DIFFERENT TYPES OF TECHNOLOGY
It is helpful to distinguish among the types of information
systems according to the technology employed. In a batch system, all inputs are processed at one time to produce the
desired output. The input data are collected and used to update the files
periodically – daily, weekly, or monthly. The data are frequently out of date in
this type of system because updating is periodic, but batch processing is very
economical. A payroll system is an example of an application that is often
operated in batch mode, because paychecks are issued periodically. The ratio of
batch processing to interactive processing, even if they have some batch
components. All applications in which a user works directly with a computer,
virtually everything other than batch processing is considered to be interactive.
An inquiry system lets us process retrieval requests for
information on-line. Often inquiry systems accept and edit input on-line for later updating in batch mode. This input is
saved in a file and is used to update the system later. A production control
system could be operated in this manner to accept input from terminals on the
factory floor during the day. Then, in the evening when the computer schedule is
less heavy, the files could be updated in a batch processing run.
A fully on-line system actually modifies files as the
information is entered from terminals. An example of an on-line system is the
American Airlines' SABRE reservations system which supports tends of thousands
terminals throughout the world.
A command and control
system or real-time system is one in which information has to be fed back
instantaneously to control an operation. For example, sensors on a missile feed
information to a computer that must process the data in time to provide guidance
control for the missile.
The most popular
architecture
today is client-server in which a
user's client workstation requests data and programs from a server, a larger
computer with a great deal of storage capacity.
