Computer Generations
 |
| What is Computer Generations? | First Generation Computers (1942-1955) |
“Generation” in computer talk
provides a framework for the growth of computer industry based on key
technologies developed. Originally, it was used to distinguish between hardware
technologies but was later extended to include both hardware and software technologies.
The custom of referring to
computer era in terms of generations came into wide use only after 1964. There
are totally five computer generations known until today. Below we describe each
generation along with its identifying characteristics. Although there is some
overlap between different generations, the approximate period shown against
each is normally accepted.
In the description below, you
will come across several new terminologies. Subsequent chapters will deal with
these terminologies in detail. The idea here is to provide an overview of the
major developments and technologies during the five generations of computers
and not to explain them in detail. Hence, this section provides an overview of
what all you are going to learn in this entire book.
First Generation Computers (1942-1955)
A vacuum tube was a fragile glass
device using filaments as a source of electronics and could control and amplify
electronic signals. It was the only high-speed electronic switching device
available in those days. These vacuum tube computers could perform computations
in milliseconds and were known as first-generation computers.
Most of the first generation
computers worked on the principle of storing program instructions along with
data in 9nerriory of computer (stored Program concept) so that they could
automatically execute a program without human intervention. Memory of these
computers used electromagnetic relays, and users fed all data and instructions
into the system using punched cards. Programmers wrote instructions in machine
and assembly languages because of lack of high-level programming languages in
those days. Since machine and assembly languages are difficult to work with,
only a few specialists understood how to program these early computers.
Characteristic features of first generation computers are as follows:
- They were the fastest calculating devices of their time.
- They were too bulky in size, requiring large rooms for installation.
- They used thousands of vacuum tubes that emitted large amount of heat and burnt out frequently. Hence, the rooms/areas in which these computers were located had to be properly air-conditioned.
- Each vacuum tube consumed about half a watt of power. Since a computer typically used more than ten thousand vacuum tubes, power consumption of these computers was very high.
- As vacuum tubes used filaments, they had a limited life. Because a computer used thousands of vacuum tubes, these computers were prone to frequent hardware failures.
- Due to low mean time between failures, these computers required constant maintenance.
- In these computers, thousands of individual components were assembled manually by hand into electronic circuits, Hence, Commercial production of these computers was difficult and costly.
- Since these computers were difficult to program and use, they had limited commercial use.
No comments:
Post a comment