Big organizations in various industries like finance, healthcare, government sector, etc. depend on mainframe systems in their day-to-day operations as mainframe systems handle and manage high volume transactions securely and efficiently. Thanks to transaction subsystems present in mainframes like CICS.
In this article, we discuss the different types of transactions in an organization and how mainframe’s CICS helps in handling those transactions.
Different transactions in an organization
Different types of transactions take place in organizations every day. Some are the queries/requests of the customers, while some are related to business operations. In either of the cases, organization should handle them well to ensure smooth functioning of the business.
Broadly, there are two different types of transactions. They are Batch Processing and Online Transaction Processing (OLTP).
Batch processing is a very old type of transaction processing where the organization first stores all requests/queries of customers in batches of files and processes them batch wise in a bulk by using software and then gives the response. Output is not immediate in batch processing and the user has to wait for response from the organization.
Online Transaction Processing (OLTP)
Unlike batch processing, online transaction processing is immediate where user will get the response immediately as soon as he sends request. All ATM transactions, payments made in supermarkets, etc., are examples of OLTP.
Again in OLTP transactions, there are short and long transactions. Short transactions are the requests that are resolved by using one or few programs and within few seconds. For example balance enquiry, address change, etc. Long transactions take few hours or days to resolve the issues and involve multiple programs to resolve the customer’s query.
CICS (Customer Information Control System)
CICS is a transaction processing system of mainframe’s operating system that handles OLTP transactions of an organization.
CICS is a collection of programs that together forms an online application programming interface (API) to customers. Customers can request services and organization can process the request and send response to customers through this API. CICS can also enable multiple users to make multiple requests at a same time via this API.
CICS has all the characteristics that an ideal transaction system should have. They are called ACID (Atomicity, Consistency, Isolation and Durability) properties of transactions.
Atomicity – Property of completely performing the transaction or not performing it at all. For example, if there is a bank transfer from one account to another, then money should be debited from one account and at the same time it should be credited into another account in order to perform the transaction completely.
Consistency – This property of CICS makes sure that the data is consistent throughout the transaction. From the above example, the money transferred should be equal before and after the transaction.
Isolation – This property is related to security. When more than one transaction is taking place at the same time, transaction should be invisible or partly visible to the third party. In the above mentioned example, the transaction is invisible to others or only the one who is involved in the transaction can see the account.
Durability – Once the transaction is complete, data should not be lost or changed. When money is transferred, the transaction should not be reversed in any situation, even when there is any system failure.