Page 13 - DCAP101_BASIC_COMPUTER_SKILLS

Basic Computer Skills

Notes developments and technologies in detail. The objective of this section is mainly to provide
an overview of what all you are going to learn in this entire book.
1.3.1 First Generation (1942-1955)

We have already discussed about some of the early computers—ENIAC, EDVAC, EDSAC,
UNIVAC 1, and IBM 701. These machines and others of their time used thousands of vacuum
tubes. A vacuum tube [see Figure 1.1](a)] was a fragile glass device, which used 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 tubes computer
could perform computations in milliseconds and were referred to as first-generation
computers.

The memory of these computers used electromagnetic relays, and all data and instructions
were fed into the system from punched cards. The instructions were written in machine and
assembly languages because high-level programming languages were introduced much
later. Since machine and assembly languages are very difficult to work with, only a few
specialists understood how to program these early computers.
Characteristic features of first-generation computers are as follows:

1. They were the fastest calculating devices of their time.
2. They were too bulky in size, requiring large rooms for installation.
3. 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.

4. 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.
5. As vacuum tubes used filaments, they had a limited life. Because a computer used
thousand of vacuum tubes, these computers were prone to frequent hardware failures.
6. Due to low mean time between failures, these computers required constant maintenance.

7. In these computers, thousands of individual components were assembled manually by
hand in to electronic circuits. Hence, commercial production of these computers was
difficult and costly.
8. Since these computers were difficult to program and use, they had limited commercial
use.

Give brief description about the first genration computer.

1.3.2 Second Generation (1955-1964)
John Bardeen, Willian Shockley, and Walter Brattain invented a new electronic switching
device called transistor [see Figure 1.1(b)] at Bell Laboratories in 1947. Transistors soon
proved to be a better electronic switching device than vacuum tubes due to their following
properties:

1. They were more rugged and easier to handle than tubes since they were made of
germanium semiconductor material rather than glass.

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