Page 15 - DCAP101_BASIC_COMPUTER_SKILLS

Basic Computer Skills

Notes
Figure 1.1: Electronic Devices Used for Manufacturing Computers of Different

Glass envelope
Plate (anode)
Cathode
Grid

(a) A Vacuum Tube (b) A Transistor (c) An IC Chip

1.3.3 Third Generation (1964-1975)
In 1958, Jack Clair Kilby and Robert Noyce invented the first integrated circuit. Integrated
circuits (called ICs) are circuits consisting of several electronic components like transistors,
resistors, and capacitors grown on a single chip of silicon eliminating wired interconnection
between components. The IC technology was also known, 0 technologies because it made
it possible to integrate larger number of circuit components into very small (less than 5 mm
square) surface of silicon, known as “chip” [see Figure l.l(c)]. Initially the integrated circuits
contained only about ten to twenty components. This technology was named small scale
integration (SSI). Later with the advancement in technology for manufacturing ICs, it became
possible to integrate up to about components on a single chip. This technology came to be
known as medium scale integration (MSI).
Computers built using integrated circuits characterized the third generation. Earlier ones
used SSI technology and later used MSI technology. ICs were smaller, less expensive to
produce, more rugged and reliable, faster in operations, dissipated less heat, and consumed
less power than circuits built by wiring electronic components manually. Hence third-
generation computers were more powerful, more reliable, less expensive, smaller, and
cooler to operate than second-generation computers.

Parallel advancements in storage technologies allowed construction of larger magnetic
core based random access memory as well as larger capacity magnetic disks and tapes.
Hence, third-generation computers typically had few megabytes (less than 5 Megabytes)
of main memory and magnetic disks capable of storing few tens of megabytes of data per
disk drive.
On software front, standardization of high-level programming languages, timesharing
operating systems, unbundling of software from hardware, and creation of an independent
software industry happened during third generation. FORTRAN and COBOL were the most
popular high-level programming languages in those days. American National Standards
Institute (ANSI) standardized them in 1966 and 1968 respectively, and the standardized
versions were called ANSI FORTRAN and ANSI COBOL. The idea was that as long as
programmers follows these standards in program writing, a program could be run on any
computer with an ANSI FORTRAN or ANSI COBOL compiler. Some more high-level

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