Information System

At present there are Four main types:

 Transaction Processing Systems (TPS)
 Decision Support Systems (DSS)
 Executive Information Systems (EIS)
 Management Information Systems (MIS

Operations Support System:

Operations Support System (OSS) performs management, inventory, engineering, planning, and repair functions.
A lot of the work on OSS has been centered on defining its architecture. Put simply, there are four key elements of OSS:

• Processes
          o the sequence of events
• Data
         o the information that is acted upon
• Applications
           o the components that implement processes to manage data
• Technology
         o how we implement the applications



1. Transaction Processing System

A transaction processing system (TPS) collects, stores, modifies and retrieves the transactions of an organization. Examples of such systems are automatic telling machines (ATMs), electronic funds transfer at point of sale (EFTPOS – also referred to as POS).

• A Transaction Processing System collects, stores, modify's and retrieves the daily transactions of a business.
• TPS systems secure and record the daily transactions of a company.

There are two types of transaction of processing:

Batch processing: where all of the transactions are collected and processed as one group or batch at a later stage.
Real-time processing: where the transaction is processed immediately

Batch Processing

In Batch processing all information that needs to be processed is collected and processed as a group at a later date.
A good example of Batch processing is Cheques, as these are collected and processed at a later date.

Three main disadvantages of batch processing are:

1. The processing schedule is pre-determined so it must wait till a set time.
2. Errors cannot be corrected during processing
3. Sorting the transaction data is expensive and time consuming.

Real time processing

Real time Processing is the immediate processing of data. It instantaneously provides confirmation of a transaction.

There are two main concerns with Real-time processing these are:

1. Concurrency, which ensures that two users cannot change the same data at any one time.
2. Atomicity, which is the ensurance that all steps in the transaction process are completed.

Real time processing is extremely expensive. Both the hardware and software.


Information systems are constantly changing and evolving as technology continues to grow. Very importantly the information systems described below are not mutually exclusive and some (especially Expert Systems, Management Information Systems and Executive Information Systems are can be seen as a subset of Decision Support Systems). However these examples are not the only overlaps and the divisions of these information systems will change over time.


Components of A Transaction Processing System:

• Users – are people who use a TPS often take the data provided by the TPS and use it in another type of information system. This is a main feature of a TPS
• Participants – are the people who conduct information processing. Success or failure of the system depends on them.
• People – people from the environment become participant when they directly enter transactions and perform validation .Eg, withdrawing money from an ATM.

Four most important characteristics of a TPS system:

• Rapid response – fast performance with rapid results
• Reliability – well designed backup and recovery with a low failure rate
• Inflexibility – treat every transaction equally
• Controlled processing – maintain specific requirements for the roles and responsibilities of different employees.

• The output from a TPS is the input to other types of information systems.
 Such as:

• DSS (Decision Support Systems) can provide the information necessary to make informed decisions.
• MIS (Management Support Systems) provides information for the organisation’s managers. Presenting basic facts.

File Types in A Transaction Processing System:

• Master file - contains information about an organisations business situation.
• Transaction file - is a collection of transaction records.
• Report file - contains data that has been formatted for presentation to a user.
• Work file - is a temporary file in the system used during the processing.
• Program file – contains instructions for the processing of data.

ACID MODEL


The ACID model is one of the oldest and most important concepts of database theory. It sets forward four goals that every database management system must strive to achieve: atomicity, consistency, isolation and durability. No database that fails to meet any of these four goals can be considered reliable.

Let’s take a moment to examine each one of these characteristics in detail:
• Atomicity states that database modifications must follow an “all or nothing” rule. Each transaction is said to be “atomic.” If one part of the transaction fails, the entire transaction fails. It is critical that the database management system maintain the atomic nature of transactions in spite of any DBMS, operating system or hardware failure.
• Consistency states that only valid data will be written to the database. If, for some reason, a transaction is executed that violates the database’s consistency rules, the entire transaction will be rolled back and the database will be restored to a state consistent with those rules. On the other hand, if a transaction successfully executes, it will take the database from one state that is consistent with the rules to another state that is also consistent with the rules.
• Isolation requires that multiple transactions occurring at the same time not impact each other’s execution. For example, if Amit issues a transaction against a database at the same time that Richa issues a different transaction; both transactions should operate on the database in an isolated manner. The database should either perform Amit’s entire transaction before executing Richa’s or vice-versa. This prevents Amit’s transaction from reading intermediate data produced as a side effect of part of Richa’s transaction that will not eventually be committed to the database. Note that the isolation property does not ensure which transaction will execute first, merely that they will not interfere with each other.
• Durability ensures that any transaction committed to the database will not be lost. Durability is ensured through the use of database backups and transaction logs that facilitate the restoration of committed transactions in spite of any subsequent software or hardware failures.