1. Give a description in your own words of the ACID properties of a transaction.
ACID (Atomicity, Consistency, Isolation and Durability) in computer science is known as a set of properties which is a unique to make sure all database transactions have high quality. Each part of ACID is shown below:
Atomicity: it has function to ensure that all transaction is done by following an “all or nothing” rule. This means if there is a transaction fail, this will affect entire transaction in the state.
Consistency: this property has function to ensure transactions which were done in database have remained on a consistent view of the data (before and after they leave data even this transaction successful or not).
Isolation: this property has function to ensure that other transaction operations can not view or access the data which is in processing state to maintain consistency in database transaction until the transactions are finished.
Durability: this property has function to keep transaction continuing after notifying of a user success and leaving no transaction in undone state. In addition, durability will help to overrun failure system problem (for example the transactions can be written into transaction logs which can be used to restore state before system failure state).
2. Describe a TP monitor environment. How can a TP monitor stop an operating system being overwhelmed?
Teleprocessing monitor (Transaction processing monitor) is defined by Wikipedia is an control program that mange the data processing between local and remote terminals to make sure all transactions are finished. In addition, it also has function to manage the data transferring between server and client when client send a request to the server (this will ensure the requesting is done so the transaction can continue on process. Besides, TP monitor ensure that all transactions are updated at the current state and it creates a high availability system by switching a failed transaction to another machine so there is no transaction lost or destroyed (the Customer Information Control System (CICS) for IBM mainframe computers is an example of TP monitor).
TP monitor stop an operating system being overwhelmed creating a new class (load balancing) if there is many incoming clients requesting that over the number of process in a server class. Furthermore, load balancing helps distribute processing and communications activity across a computer system so there is no overwhelmed in single part.
References
Wikipedia (n.d.). Teleprocessing monitor. Retrieved 16 October 2009 from http://en.wikipedia.org/wiki/Teleprocessing_monitor
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