Technology has made the world look like a “global village”. Village in the sense, it has made it look smaller than it is really and this has been made possible by communication. Either picking up your phone to call someone that is a thousand miles away from you or making calls from your system (Skype), communication can be established. Communication is “relatively” cheap. It is cheaper than actually going to see the person in person. It is safe to say that the computers are “talking” to one another.
But let us not get ahead of ourselves; communication and technology were never this straightforward in the past. We had eras when only products from the same Vendor could only communicate. For example IBM systems could only communicate with each other.
So today we shall be looking at how communication was
Batch – oriented configuration
This is the oldest form of communications between systems and other resources. Each resource is assigned to a system and the resource isn’t released till the task is completed, hence the name “batch”. For example, if we have 3 systems, 1 printer, 1 scanner. One system is assigned the printer and another one the scanner has while the last one is free. If the last system wants to print it has to wait for the system using the printer, so if it has a thousand and one jobs to print, it has to finish before it is released. Pretty inefficient and wasting a lot of time being idle.
Time – sharing Multi-user
Ideas were worked on to help eliminate the problem of time wasting; the idea of time sharing was accepted at that time. Time sharing in the sense that each system was given equal time with the resources. So once the time elapses, the resource is released so another can take it. I am sure some of you are wondering what if the next available system doesn’t need it at that time, wouldn’t it be needless holding onto it. This was also worked on, so after a while if the system isn’t using it, it is forced to release it.
Single – User
It got to be a point when it was necessary for a house to have a complete system and other resources without it been shared by other systems. This is found in most homes where 1 system is connected to a printer.
After the phase of single user communications, it was thought of that it will be cost effective if computer systems could share resources. Share in the sense that they can access them whenever they needed it without waiting for a period of time or a batch to finish. Switches and bridges were introduced so as to solve the problem. It appears that all the systems were in the same area within few meters away from each other. Hence the name, Local Area Network, or LAN as it is commonly known as.
Private WANs (Metropolitan)
After the development of LAN, technology began to grow and the need for a larger network .Mentioned earlier, LAN could only be effective until a certain distance. MAN and WAN came into place. MAN is the acronym for Metropolitan Area Network and it was sufficient for connecting networks within a geographical area while WAN is the acronym for Wide Area Network.
The Internet is a public WAN, but there are many ways to create a business model or private version. A private network is essentially two or more LANs connected to each other. For example, a company with offices in Lagos, Portharcourt and Abuja might have a LAN setup at each office. Through leased telephone lines, all three LANs can communicate with each other, forming a WAN.
Publicly Switched Data Networks (WAN)
PSDN stands for public switched data network; this is another alternate to WAN. A PSDN is a way to lease time to access other information by other computers. It is maintained and developed by a vendor. They might lease this “line” for personal use or to an organization, which is more likely.
PSDNs save cost because a company does not have to lease the entire network for that given time; all they have to do is pay for the access to the network.
The location where the PSDN networked is accessed is called POP (point of preference). An example of this is the phone number you dial to call someone else. Once a site has connected to the proper PSDN POP it also has obtains access to other sites connected to the PSDN. Basically the company or organization is paying for the traffic it is sending via the lines to PSDN. There are three protocols associated with PSDN, Frame Relay, ATM and Ethernet. ATM supports the fastest speed and also can support voice and data communications. They operate at different speeds and the client can choose which one fits them the best.
The Internet is a worldwide, publicity accessible series of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP). It is a “network of networks” that consists of millions of smaller domestic, academic, business, and government networks, which together carry various information and services, such as electronic mail, online chat, file transfer, and the interlinked web pages and other resources of the World Wide Web (www).
An intranet is a computer network that shares information, operational systems, or computing services within an organization. The term simply means a network within an organization. Sometimes, the term refers only to the organization’s internal website, but may consist of multiple local area networks. The objective is to organize each individual’s desktop with minimal cost, time and effort to be more productive, cost efficient, timely, and competitive.