I borrowed this book before Hari Raya Aidilfitri this year from National Library (PNM). After reading it , I think this book mainly covers chapter about Autonomic Computing – the concepts , infrastructure and applications and the field , theory about Autonomic Computing.
The term autonomic computing was coined in 2001 by Paul Horn , senior vice president of research for IBM. According to Horn , the industry’s focus on creating smaller , less expensive , and more powerful systems was fueling the problem of complexity. Left unchecked , he said , this complexity would ultimately prevent companies from “moving to the next era of computing” and , therefore the next era of business. In response , he issued a “Grand Challenge” to the IT industry to focus on the development of autonomic systems that could manage themselves.
Current State of Autonomic Computing.
The most visible sign to IT staffs has been the incorporation of self-managing autonomic capabilities into individual products. Today , at every level of the infrastructure , vendors are embedding autonomic capabilities within their products. Chip can now sense change and alter the configuration of circuitry to enhance processor performance or avoid potential problems. Databases can automatically tune themselves as workload fluctuates and optimize performance as data organization changes. Networking components can intelligently route traffic. Blade servers can automatically populate new blades with the required software as they’re plugged in. The list goes on.
Autonomic computing is about creating systems that are self-aware and self-managing to help reduce management complexity , increase availability , and enhance flexibility. Great strides have already been made in this emerging field. Further chapters in this book provide in-depth discussion on autonomic computing architecture , implementation models , design, and application in both academia and industry to demonstrate what exists today and what will be possible in the future.
Although autonomic computing was proposed as a way of handling the growing complexity of some large computing systems , its associated properties are desirable in software of any size. Indeed , most software typically contains some aspects of selft-management , and that use is growing through inclusion of features such as automated updates over the internet.
A large autonomic computing system cannot be composed from autonomic components. The configuration of the components would not self-adapt , the composition could oscillate , and individual components might become bottlenecks. In order to have system-wide autonomy , a system-wide feedback loop is necessary.
p/s: – Some of the article above is an excerpt from the book Autonomic Computing – Concepts , Infrastructure and Applications edited by Manish Parashar and Salim Hariri – CRC Press.
TCP/IP Sockets in Java.
This book also I borrowed from National Library (PNM) before Hari Raya Aidilfitri this year…The books covers the TCP/IP programming sockets in Java language.How we can implement sockets in java language , the coding and so on….
A socket is an abstraction through which an application may send and receive data , in much the same way as an open file handle allows an application to read and write data to stable storage. A socket allows an application to plug in to the network and communicate with other applications that are plugged in to the same network. Information written to the socket by an application on one machine can be read by an application on different machine and vice versa.
Java provides two classes for TCP:Socket and ServerSocket. An instance of socket represents one end of a TCP connection. A TCP connection is an abstract two-way channel whose end are each identified by an IP address and port number. Before being used for communication , a TCP connection must go through a setup phase , which starts with the client’s TCP sending a connection request to the server’s TCP. An instance of ServerSocket listen for TCP connection requests and creates a new Socket instance to handle each incoming connection. Thus , servers handle both ServerSocket and Socket instances , while clients use only Socket.
UDP provides an end-to-end service different from that TCP. In fact , UDP performs only two functions: 1)it adds another layer of addressing (ports) to that IP , and 2) it detects some forms of data corruption that may occur in transit and discards any corrupted messages. Because of this simplicity , UDP sockets have some different characteristics from the TCP sockets we saw earlier.
Another difference between UDP sockets and TCP sockets is the way that they deal with message boundaries: UDP socket preserve them. This makes receiving an application message simpler , in some ways , than it is with TCP sockets.
p/s:- Some of the article is an excerpt from the book TCP/IP Sockets in Java – Practical guide for programmers , written by Kenneth L. Calvert and Michael J.Donahoo publish by Morgan Kaufmann.