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e\L-lovely-eng\comm2-1.pmd IInd 16-9-11 IIIrd 27-12-11 IVth 4-1-12

Information and Communication Technology Applications

Notes
Semiconductor is a material, typically crystalline, which allows current to flow under
certain circumstances. Common semiconductors are silicon, germanium, and gallium
arsenide. Semiconductors are used to make diodes, transistors and other basic “solid
state” electronic components.

The third generation computers, removed many drawbacks of second generation computers. The
third generation computers were even smaller in size, very less heat generated and required very
less power as compared to earlier two generation of computers. These computers required less
human labour at the assembly stage. Although, third generation computers were also still faster
and even more reliable, they also had few disadvantages. They still had less storage capacity,
relatively slower performance and thus could not fulfill the requirements of the users and
programmers.

1. IBM 360, developed by IBM in 1964 was the first product line designed as a family.
2. PDP-8, developed by DEC in 1965 was the first mass-market minicomputer as shown in Figure 2.7.

Figure 2.7: PDP-8

3. PDP-11, developed by DEC in 1970 was the first highly successful minicomputer.
4. CRAY-1, developed by Cray in 1976 was the first supercomputer as shown in Figure 2.8.

Figure 2.8: CRAY-1

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