Atransaction processing system (TPS) is asoftware system, or software/hardware combination, that supportstransaction processing.
The first transaction processing system wasSABRE, made byIBM forAmerican Airlines, which became operational in 1964.[1] Designed to process up to 83,000 transactions a day, the system ran on twoIBM 7090 computers. SABRE was migrated toIBM System/360 computers in 1972, and became an IBM product first asAirline control Program (ACP) and later asTransaction Processing Facility (TPF). In addition to airlines, TPF is used by large banks, credit card companies, and hotel chains.
TheHewlett Packard EnterpriseNonStop system (formerlyTandem NonStop) is a hardware and software system designed forOnline Transaction Processing (OLTP) introduced in 1976.[2] The system provides an extreme level of availability and data integrity.
Transaction processing is distinct from and can be contrasted with other computer processing models, such asbatch processing,time-sharing, andreal-time processing.[10]
Batch processing is execution of a series of programs (jobs) on a computer without manual intervention. Several transactions, called abatch are collected and processed at the same time. The results of each transaction are not immediately available when the transaction is being entered;[1] there is a time delay.
"Real time systems attempt to guarantee an appropriate response to a stimulus or request quickly enough to affect the conditions that caused the stimulus."[10] Each transaction in realtime processing is unique; it is not part of a group of transactions.
A Transaction Processing System (TPS) is an information system that collects, stores, modifies, and retrieves the data transactions of an enterprise. Transaction processing systems also attempt to provide predictable response times to requests, although this is not as critical as real-time systems. Rather than allowing the user to run arbitrary programs as time-sharing, transaction processing allows only predefined, structured transactions. Each transaction is usually short, and each transaction's processing activity is programmed in advance. It is an MIS model.
The following features are considered important in evaluating transaction processing systems.[10]
Fastperformance with a rapid response time is critical. Transaction processing systems are usually measured by the number of transactions they can process in a given period of time.
The system must be available during the time period when the users are entering transactions. Many organizations rely heavily on their TPS; a breakdown will disrupt operations or even stop the business.
The system must be able to handle hardware or software problems without corrupting data. Multiple users must be protected from attempting to change the same piece of data at the same time, for example two operators cannot sell the same seat on an airplane.
Often users of transaction processing systems are casual users. The system should be simple for them to understand, protect them from data-entry errors as much as possible, and allow them to easily correct their errors.
The system should be capable of growth at incremental costs, rather than requiring a complete replacement. It should be possible to add, replace, or update hardware and software components without shutting down the system.
Transactions may be collected and processed as in batch processing. Transactions will be collected and later updated as a batch when it is convenient or economical to process them. Historically, this was the most common method as theinformation technology did not yet exist to allow real-time processing.
This is the immediate processing of data. It provides instant confirmation of a transaction. It may involve a large number of users who are simultaneously performing transactions which change data. Because of advances in technology (such as the increase in the speed ofdata transmission and larger systems and networkingbandwidth), real-time updating is possible.
A database is an organized collection of data. Databases offer fast retrieval times for non-structured requests as in a typical transaction processing application.
Databases for transaction processing may be constructed using hierarchical, network, or relational structures.
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The following features are desirable in a database system used in transaction processing systems:
Since business organizations have become very dependent on transaction processing, a breakdown may disrupt the business' regular routine and stop its operation for a certain amount of time. In order to prevent data loss and minimize disruptions well-designedbackup andrecovery procedures must exist and be adhered to. The recovery process can rebuild the system when it goes down.
There are two main types of back-up procedures:grandfather-father-son andpartial backups:
This procedure involves taking complete backups of all data at regular intervals – daily, weekly, monthly, or whatever is appropriate. Multiple generations of backup are retained, often three which gives rise to the name. The most recent backup is the son, the previous the father, and the oldest backup is the grandfather. This method is commonly used for abatch transaction processing system with amagnetic tape drive. If the system fails during a batch run, the master file is recreated by restoring the son backup and then restarting the batch. However, if the son backup fails, is corrupted or destroyed, then the previous generation of backup (the father) is used. Likewise, if that fails, then the generation of backup previous to the father (i.e. the grandfather) is required. Of course the older the generation, the more the data may be out of date.
Partial backups
Partial backups generally contain only records that have changed. For example, a full backup could be performed weekly, and then partial backups taken nightly. Recovery using this scheme involves restoring the last full backup and then restoring all partial backups in order to produce an up-to-date database. This process is quicker than taking only complete backups, at the expense of longer recovery time.
