Systems Communicate with Other Systems Using Networks

Up to this point In our tour of systems, we have treated a system as an isolated collection of hardware  and software. In practice, modern systems are often linked to other systems by networks. From the point of view of an individual system, the network can be viewed as just another I/O device. Technical Data used in the field explained in computer courses in Rawalpindi.

When the system copies a sequence of bytes from main memory to the network adapter, the data flows across the network to another machine, instead of, say, to a local disk drive. Similarly, the system can read data sent from other machines and copy this data to its main memory.

With the advent of global networks such as the Internet, copying information from one machine to another has become one of the most important uses of computer systems. For example, applications such as email, instant messaging, the World Wide Web, FTP, and telnet are all based on the ability to copy information over a network. Some more details of computer courses in Rawalpindi are as under.

Returning to our hello example, we could use the familiar telnet application to run hello on a remote machine. Suppose we use a telnet client running on our local machine to connect to a telnet server on a remote machine. After we log in to the remote machine and run a shell, the remote shell is waiting to receive an input command. From this point, running the hello program remotely involves the five basic.

After we type the “hello” string to the telnet client and hit the enter key, the client sends the string to the telnet server. After the telnet server receives the string from the network, it passes it along to the remote shell program. Next, the remote shell runs the hello program, and passes the output line back to the telnet server. Finally, the telnet server forwards the output string across the network to the telnet client, which prints the output string on our local terminal.

This concludes our initial whirlwind tour of systems. An important idea to take away from this discussion is that a system is more than just hardware. It is a collection of intertwined hardware and systems software that must cooperate in order to achieve the ultimate goal of running application programs. The rest of this book will fill in some details about the hardware and the software, and it will show how, by knowing these

details, you can write programs that are faster more reliable, and more secure.

To close out this chapter, we highlight several important concepts that cut across all aspects of computer systems. We will discuss the importance of these concepts at multiple places within the book. TSK Training for Skills and Knowledge is the best institute in Rawalpindi Islamabad for Pakistani Students who wants to join computer courses in Rawalpindi.