This preview shows page 1. Sign up to view the full content.
Unformatted text preview: .
2. They were too bulky in size requiring large rooms for installation.
3. Thousands of vacuum tubes that were used emitted large amount of heat and burnt
out frequently. Hence the rooms/areas in which these computers were located had to be
4. Each vacuum tube consumed about half a watt of power. Since a computer typically
used more than ten thousand vacuum tubes, the power consumption of these computers
was very high.
5. As vacuum tubes used filaments, they had a limited life. Since thousands of vacuum
tubes were used in making one computer, these computers were prone to frequent
hardware failures, their mean time between failures being as low as an hour.
Due to such low mean time between failures, these computers required almost
In these computers, thousands of individual components had to be assembled
manually by hand into functioning circuits. Hence commercial production of these
computers was difficult and costly.
Since these computers were difficult to program and use, they had limited
Second Generation (1955-1964)
A new electronic switching device called transistor [see Figure 1.2(b)] was invented at
Bell Laboratories in 1947 by John Bardeen, Willian Shockley, and Walter Brattain.
Transistors soon proved to be a much better electronic switching device than the 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.
They were highly reliable as compared to tubes since they had no part like a
filament, which could burn out. 3. They could switch much faster (almost ten times faster) than tubes. Hence switching
circuits made of transistors could operate much faster than their counterparts made of
4. They consume almost one-tenth the power consumed by a tube.
5. They were much smaller in size than a tube.
6. They were less expensive to produce.
7. They dissipated much less heat as compared to vacuum tubes.
View Full Document
- Spring '14