personal computers
competitive operating systems
IBM (International Business Machine)
to enter the fray
computer of choice
to fall by the wayside ;
to survive onslaught
word size ;
soft-copy output , -
hard-copy output
online storage
offline storage
input media
output media
general - purpose ;
stand-alone
to plug in ;
leisure activities
2. ,
.
PERSONAL COMPUTERS
Personal computers are supposed to appear in the late 1970s. One of the first and most popular personal computers was the Apple II, introduced in 1977 by Apple Computer. During the late 1970s and early 1980s, new models and competitive operating systems seemed to appear daily. Then, in 1981, IBM entered the fray with its first personal computer, known as the IBM PC. The IBM PC quickly became the personal computer of choice, and most other personal computer manufacturers fell by the way-side. One of the few companies to survive IBM's onslaught was Apple Computer, which is sure to remain a major player in the personal computer marketplace. In less than a decade the microcomputer has been transformed from a calculator and hobbyist's toy into a personal computer for almost everyone.
What is a personal computer? How can this device be characterized?
First, a personal computer being microprocessor-based, its central processing unit, called a microprocessor unit, or MPU, is concentrated on a single silicon chip.
Second, a PC has a memory and word size that are small er than those of minicomputers and large computers. Typical word sizes are 8 or 16 bits, and main memories range in size from 16 to 512 K.
Third, a personal computer uses smaller, less expensive, and less powerful input, output and storage components than do large computer systems. Most often, input is by means of a keyboard, soft-copy output being displayed on
a cathode-ray tube screen. Hard-copy output is produced
on a low-speed character printer.
A PC employs floppy disks as the principal online and
offline storage devices and also as input and output me
dia.
Finally, a PC is a general-purpose, stand-alone system
that can begin to work when plugged in and be moved
from place to place.
Probably the most distinguishing feature of a personal computer is that it is used by an individual, usually in an interactive mode. Regardless of the purpose for which it is used, either for leisure activities in the home or for business applications in the office, we can consider it to be a personal computer.
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1. When did the first personal computer appear? 2. What was one of the first PC model? 3. What is a personal computer? 4. What are the four main characteristics of a PC? 5. What does the term microprocessor-based mean? 6. What are the typical word sizes of a PC? 7. How is input carried out in personal
computers? 8. What principle storage devices do PC use? 9. What kind of a system is a PC? 10. What differs personal computers from large computer systems?
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