Aspect #04 18 января 1998

History of the PC - The Origin of PCs.

   A personal computer can determine the
in two ways: as a computer, which can
operated by one person, or as
toy, has become a powerful weapon
business. In many cases these two definitions mean the same 
thing. IBM PC embodies the very idea of ​​a personal computer. 
Only recently, these computers were replaced by new machines - 
the so-called IBM personal systems and computers

Apple company's Macintosh. Nevertheless, IBM PC
was the technological foundation for
all (or nearly all) personal computers. This system has 
established the first standards that have helped other 
producers to achieve success and who have indicated way to 
progress. 


ORIGIN OF PERSONAL COMPUTERS



   The climax came on Aug. 12, 1981
year, when it was first presented at the
IBM PC. And today all manufacturers
personal computers are affected by the influence of those 
historic decisions. 

   For a complete understanding of personal computers, how they 
evolve, we must begin with an introduction to basic concepts of 
those decisions. Too often, the development of personal 
computers are faced with constraints that seem in no way 
justifiable. 

   But one thing is obvious: personal computers - not just the 
brainchild of IBM. After the public presentation of the first 
PC, even in the IBM is not aware of - what they did. Followed 
by a dizzying success, culminating initially, even to the 
deficit and the incredible success of traders from IBM, which 
could turn silicone into gold.



       Contradictory Development


      Once there has been a great success
first PC, IBM classify their development for centuries. Her 
brilliant hunch was based equally on the prognosis for success 
their development and risk. IBM wanted provide their offspring, 
satisfying both amateurs and professionals. A desktop computer 
has great potential, and IBM did not want to lose them, as was 
the case with a mini-computer (here, the greatest success came 
in the share of firms DEC).


      Creating a first model of Table
computer, the company carefully developed
their own unique solutions to
all key issues. And then we used these original solutions, so
and accepted while other manufacturers. If failures have 
occurred - was used by another option, but only within adopted 
a strategic concept. 



               COMPETITORS



      To understand why these
elements used in designing
PC, is necessary to recall what happened
while the computer market.

      In 1980, the concept of "personal
Computer interpreted broadly. Market
Logistics is very varied. However, all personal computers can 
be divided into three large groups. In two of them dominated by 
one main manufacturer. The third combines the use of one 
operating system. 


             APPLE Computer


      The most important and long-term rival for popularity, 
which has managed to survive with their original decisions, was 
and remains the APPLE-2. (Previous development was more design 
work than the commercial model). Development of APPLE-2 had the 
original and promising solutions, which are soon

time were used to create IBM PC.

      APPLE-2 had a single-board construction and expansion bus 
which allows to connect additional devices. The keyboard was 
placed in a separate building, which corresponded to the 
simple, practical and effective approach.


      As the central was taken
very reliable at the time the microprocessor 6502, which 
carried out the eight-operation at about million operations per 
second. 

      The drawback was the lack of
lowercase characters, little RAM - only 8 kilobytes, and the 
ability to handle only 40 columns characters on the screen. To 
increase the volume memory used magnetic tape,

run from an ordinary cassette tape recorder.

      Later, in addition to the APPLE-2 were
developed bitmap graphics, disk operating system for managing
memory and lower case for
characters that could be placed on
screen in eighty columns. Some
of these solutions are not ripe at the time
appearance of the first PC or required engineering genius. 
Somehow, with time All these problems have been solved. 
Especially Much progress has been made with structural memory, 
where, for example, the variables screen characters were stored 
in different blocks of memory. 


           Tandy / Radio Snack


      Above the second camp manufacturers
Desktops above all hovered
Flag Company Radio Snack. Street vendors
were well-known products of this company -
on batteries and toys to watches and phones. Soon the number of 
additional and computers. Some of them were made by own 
technology, worked on microprocessor and had their own 
operating system.


      The company produces a wide range of computers, but most
spread during an appearance IBM PC
had a TRS-80 model. It was a table
computer, which in one case
place the monitor, keyboard and all
electronics. We used a microprocessor
Z80, had floppy disk drives and
magnetic tape. But the most famous
operating system was TRS-DOS, nicknamed the "cheesy" operating 
system.  This partly explains the nickname, why

model officially disappeared from the market. After
few years, "cheesy" jokes, Radio
Snack transformed to Tandy Corporation. And in this case has 
disappeared not only abbreviation for TRS, but also a trademark 
of Radio Snack on all computers produced. 


                 CP / M


      The third group of small producers
Computer ob'edinyala firm Control
Program for Microcomputers (CP / M). Company
produced a powerful and widespread computers with 
microprocessors 8080 and Z80 and flexible operating system. Low 
cost and reliability have led to the wide dissemination of this 
model and its use as a standard.


      Typical computers CP / M allowed
process the text at 80 columns display
using lower case letters. Tekstoorientirovanny display usually 
had a teletype interface. This interface was developed with the 
establishment of separate terminals and the central processor. 
Communications between them is carried out consistently

and one bit.

      The combination of microprocessor and operating system 
allowed to find a wide use of computers: from the preparation

text to database management. This
it was just what was needed for the business and allowed to 
consider this model the standard desktop computer. In the 
beginning 80's most biznesoorientirovannogo software (usually

consisting of no more than a few dozen lines of code in BASIC) 
was designed to CP / M. 


         to be continued ...


                   Prepared for publication

                 Sergey Aniskin (VEC: 01:00)