Java Reference
In-Depth Information
At the end of the 19th century, U.S. Census officials needed help in accurately tabulating
the census data. Herman Hollerith invented a calculating machine that ran on electricity
and used punched cards to store data. Hollerith's machine was immensely successful.
Hollerith founded the Tabulating Machine Company, which later became the computer
and technology corporation known as IBM.
The first computer-like machine was the Mark I. It was built, in 1944, jointly by IBM
and Harvard University under the leadership of Howard Aiken. Punched cards were used
to feed data into the machine. Mark I was 52 feet long, weighed 50 tons, and had 750,000
parts. In 1946, ENIAC (Electronic Numerical Integrator and Calculator) was built
at the University of Pennsylvania. It contained 18,000 vacuum tubes and weighed
some 30 tons.
The computers that we know today use the design rules given by John von Neumann in
the late 1940s. His design included components such as arithmetic logic unit, control
unit, memory, and input/output devices. These components are described in the next
section. Von Neumann computer design makes it possible to store the programming
instruction and the data in the same memory space. In 1951, the UNIVAC (Universal
Automatic Computer) was built and sold to the U.S. Census Bureau.
In 1956, the invention of the transistors resulted in smaller, faster, more reliable, and more
energy-efficient computers. This era also saw the emergence of the software development
industry with the introduction of FORTRAN and COBOL, two early programming
languages. In the next major technological advancement, transistors were replaced by tiny
integrated circuits or ''chips.'' Chips are smaller and cheaper than transistors and can
contain thousands of circuits on a single chip. They give computers tremendous proces-
sing speed.
In 1970, the microprocessor, an entire CPU on a single chip, was invented. In 1977,
Stephen Wozniak and Steven Jobs designed and built the first Apple computer in their
garage. In 1981, IBM introduced its personal computer (PC). In the 1980s, clones of the
IBM PC made the personal computer even more affordable. By the mid-1990s, people
from many walks of life were able to afford them. Computers continue to become faster
and less expensive as technology advances.
Modern-day computers are very powerful, reliable, and easy to use. They can accept
spoken-word instructions and imitate human reasoning through artificial intelligence.
Expert systems assist doctors in making diagnoses. Mobile computing applications are
growing significantly. Using hand-held devices, delivery drivers can access global posi-
tioning satellites (GPS) to verify customer locations for pickups and deliveries. Cell
phones can check your e-mail, make airline reservations, see how stocks are performing,
and access your bank accounts.
Although there are several categories of computers, such as mainframe, midsize, and
micro, all computers share some basic elements.
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