1. ACID is stand for Atomicity , Consistency, Isolation and Durability ( Microsoft, 2009)
- Atomicity is related to the begin and end of transation statement, once is started just like an atomic and the work is done.
- Consistency preserves data stability and transform from one to another
- Isolation allows concurrency of transaction to behave as one of the transaction running under the system
- Durability is a unit of recovery
2. Transaction processing monitors have been evolving for about 30 years (CICS was introduced in 1968) and have become powerful, high-speed server platforms for mission-critical applications. Some TP products like CICS and TUXEDO. TP monitors are operating systems for business systems whose applications are written in languages like COBOL. It may seem strange to call a TP monitor an "operating system," but because they control an application's entire environment, it's a fitting description. TP monitor systems automatically manage the entire environment that a business system runs in, including transactions, resource management, and fault tolerance. The business logic in TP monitors is made up of procedural applications that are often accessed through network messaging or remote procedure calls (RPC), which are ancestors of RMI. Messaging allows a client to send a message directly to a TP monitor requesting that some application be run with certain parameters. It's similar in concept to the Java event model. Messaging can be synchronous or asynchronous, meaning that the sender may or may not be required to wait for a response. RPC is a distributed mechanism that allows clients to invoke procedures on applications in a TP monitor as if the procedure was executed locally. The primary difference between RPC and RMI is that RPC is used for procedure -based applications and RMI is used for distributed object systems. With RMI, methods can be invoked on a specific object identity, a specific business entity. In RPC, a client can call procedures on a specific type of application, but there is no concept of object identity. RMI is object oriented; RPC is procedural. (O' Reilly. 2001)
Example Show the TP Monitor Process (ETH Zuerich, n.d.)
3. RPC is a point to point protocol in the sense that it supports the interaction between two entities: the client and the server, when there are more entities interaction with each other ( a client with two servers, a client with a server and the server with a database), RPC treats the call as independent of each other. However, the calls are not independent. Transactional RPC is the additional language contstructs and run time support to bundle serveral RPC calls into an atomic unit Message Oriented Middleware (MOM) -products provide an assured, asyncronous and connectionless method to exchange messages between processes. (ETH Zuerich, n.d.)
Digaram shows the basic MOM:
4. One-phase atomic commit protocol can have the decision to abort the process in server, this will affect the stability and consistency of the transaction, however, two phase commit protocol involved in the client side as well in order to abort the transaction, therefore, it is more secure and consistency on the transaction process.
- Atomicity is related to the begin and end of transation statement, once is started just like an atomic and the work is done.
- Consistency preserves data stability and transform from one to another
- Isolation allows concurrency of transaction to behave as one of the transaction running under the system
- Durability is a unit of recovery
2. Transaction processing monitors have been evolving for about 30 years (CICS was introduced in 1968) and have become powerful, high-speed server platforms for mission-critical applications. Some TP products like CICS and TUXEDO. TP monitors are operating systems for business systems whose applications are written in languages like COBOL. It may seem strange to call a TP monitor an "operating system," but because they control an application's entire environment, it's a fitting description. TP monitor systems automatically manage the entire environment that a business system runs in, including transactions, resource management, and fault tolerance. The business logic in TP monitors is made up of procedural applications that are often accessed through network messaging or remote procedure calls (RPC), which are ancestors of RMI. Messaging allows a client to send a message directly to a TP monitor requesting that some application be run with certain parameters. It's similar in concept to the Java event model. Messaging can be synchronous or asynchronous, meaning that the sender may or may not be required to wait for a response. RPC is a distributed mechanism that allows clients to invoke procedures on applications in a TP monitor as if the procedure was executed locally. The primary difference between RPC and RMI is that RPC is used for procedure -based applications and RMI is used for distributed object systems. With RMI, methods can be invoked on a specific object identity, a specific business entity. In RPC, a client can call procedures on a specific type of application, but there is no concept of object identity. RMI is object oriented; RPC is procedural. (O' Reilly. 2001)
Example Show the TP Monitor Process (ETH Zuerich, n.d.)
3. RPC is a point to point protocol in the sense that it supports the interaction between two entities: the client and the server, when there are more entities interaction with each other ( a client with two servers, a client with a server and the server with a database), RPC treats the call as independent of each other. However, the calls are not independent. Transactional RPC is the additional language contstructs and run time support to bundle serveral RPC calls into an atomic unit Message Oriented Middleware (MOM) -products provide an assured, asyncronous and connectionless method to exchange messages between processes. (ETH Zuerich, n.d.)
Digaram shows the basic MOM:
4. One-phase atomic commit protocol can have the decision to abort the process in server, this will affect the stability and consistency of the transaction, however, two phase commit protocol involved in the client side as well in order to abort the transaction, therefore, it is more secure and consistency on the transaction process.
References:
1. Microsoft, 2009, " ACID Properties"
<http://msdn.microsoft.com/en-us/library/aa719484.aspx>2.O' Reilly, 2001,"Transaction Processing Monitor "
<http://docstore.mik.ua/orelly/java-ent/ebeans/ch01_05.htm>
3. ETH Zuerich, n.d., " Example of TP Monitors"
<http://www.iks.inf.ethz.ch/education/ws05/eai/slides/lec3.pdf>
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