What Is Computer And Computer Genaration

Computer is a electronic device which is capable of receiving information (data) in a particular form and of performing a sequence of operations in accordance with a predetermined but variable set of procedural instructions (program) to produce a result in the form of information or signals.A computer is generally defined as a programmable machine. The two principal characteristics of a computer are: it responds to a specific set of instruction in a well-defined manner and it can executed a prerecorded list of instructions (a program).A computer is an electronic device that manipulates information, or data. It has the ability to store, retrieve, and process data. You probably already know that you can use a computer to type documents, send email, play games, and browse the Web. You can also use it to edit or create  spreadsheets, presentations, and even videos.Throughout this tutorial, we'll show you some of the most important things you need to know about computers, including how to set up your computer, how to interact with the desktop and operating system, and what kinds of computers are available. We'll also introduce you to some basic troubleshooting strategies you can use if your computer isn't working correctly.

Generation  Description
	First Generation The period of first generation: 1946-1959. Vacuum tube based.
	Second Generation The period of second generation: 1959-1965. Transistor based.
	Third Generation The period of third generation: 1965-1971. Integrated Circuit based.

The the late 1960s and early 70s, there was much talk about "generations" of computer technology. This photo illustrates what were commonly known as the three generations:

1. First generation: Vacuum tubes (left). Mid 1940s. IBM pioneered the arrangment of vacuum tubes in pluggable modules such as the one shown here on the left. The IBM 650 was a first-generation computer.
2. Second generation: Transistors (right). 1956. The era of miniaturization begins. Transistors are much smaller than vacuum tubes, draw less power, and generate less heat. Discrete transistors are soldered to circuit boards like the one shown, with intereconnections accomplished by stencil-screened conductive patterns on the reverse side. The IBM 7090 was a second-generation computer.
3. Third generation: Integrated circuits (foreground), silicon chips contain multiple transistors. 1964. A pioneering example is the ACPX module used in the IBM 360/91, which, by stacking layers of silicon over a ceramic substrate, accommodated over 20 transistors per chip; the chips could be packed together onto a circuit board to achieve unheard-of logic densities. The IBM 360/91 was a hybrid second- and third-generation computer.

Omitted from this taxonomy is the "zeroth" generation computer based on metal gears (such as the IBM 407) or mechanical relays (such as the Mark I), and the post-3rd generation computers based on Very Large Scale Integrated (VLSI) circuits.

Generation in computer terminology is a change in technology a computer is/was being used. Initially, the generation term was used to distinguish between varying hardware technologies. But nowadays, generation includes both hardware and software, which together make up an entire computer system.
There are totally five computer generations known till date. Each generation has been discussed in detail along with their time period and characteristics. Here approximate dates against each generations have been mentioned which are normally accepted.