119321250-History-of-Computer-Programming.ppt

What is Computer Programing?
• Computer programming (often shortened to
programming or coding) is the process of writing,
testing, debugging/troubleshooting, and maintaining
the source code of computer programs. This source
code is written in a programming language. The code
may be a modification of an existing source or
something completely new. The purpose of
programming is to create a program that exhibits a
certain desired behaviour (customization). The process
of writing source code often requires expertise in many
different subjects, including knowledge of the
application domain, specialized algorithms and formal
logic.

Inventions……
• The concept of devices that operate following a pre-defined
set of instructions traces back to Greek Mythology, notably
Hephaestus and his mechanical servants[3]. The Antikythera
mechanism was a calculator utilizing gears of various sizes and
configuration to determine its operation. The earliest known
programmable machines (machines whose behavior can be
controlled and predicted with a set of instructions) were Al-
Jazari's programmable Automata in 1206.[4] One of Al-Jazari's
robots was originally a boat with four automatic musicians
that floated on a lake to entertain guests at royal drinking
parties. Programming this mechanism's behavior meant
placing pegs and cams into a wooden drum at specific
locations.

• History of programming
• See also: History of programming languages
• Wired plug board for an IBM 402 Accounting
Machine.

History….
• In the late 1880s Herman Hollerith invented the recording of data
on a medium that could then be read by a machine. Prior uses of
machine readable media, above, had been for control, not data.
"After some initial trials with paper tape, he settled on punched
cards..."[7] To process these punched cards, first known as "Hollerith
cards" he invented the tabulator, and the key punch machines.
These three inventions were the foundation of the modern
information processing industry. In 1896 he founded the Tabulating
Machine Company (which later became the core of IBM). The
addition of a control panel to his 1906 Type I Tabulator allowed it to
do different jobs without having to be physically rebuilt. By the late
1940s there were a variety of plug-board programmable machines,
called unit record equipment, to perform data processing tasks
(card reading). Early computer programmers used plug-boards for
the variety of complex calculations requested of the newly invented
machines.

History….
• The invention of the Von Neumann architecture allowed
computer programs to be stored in computer memory.
Early programs had to be painstakingly crafted using the
instructions of the particular machine, often in binary
notation. Every model of computer would be likely to need
different instructions to do the same task. Later assembly
languages were developed that let the programmer specify
each instruction in a text format, entering abbreviations for
each operation code instead of a number and specifying
addresses in symbolic form (e.g. ADD X, TOTAL). In 1954
Fortran, the first higher level programming language, was
invented. This allowed programmers to specify calculations
by entering a formula directly (e.g. Y = X*2 + 5*X + 9).

History…..
• The program text, or source, was converted into
machine instructions using a special program called a
compiler. Many other languages were developed,
including ones for commercial programming, such as
COBOL. Programs were mostly still entered using
punch cards or paper tape. (See computer
programming in the punch card era). By the late 1960s,
data storage devices and computer terminals became
inexpensive enough so programs could be created by
typing directly into the computers. Text editors were
developed that allowed changes and corrections to be
made much more easily than with punch cards.

History….
• As time has progressed, computers have made giant leaps in the
area of processing power. This has brought about newer
programming languages that are more abstracted from the
underlying hardware. Although these more abstracted languages
require additional overhead, in most cases the huge increase in
speed of modern computers has brought about little performance
decrease compared to earlier counterparts. The benefits of these
more abstracted languages is that they allow both an easier
learning curve for people less familiar with the older lower-level
programming languages, and they also allow a more experienced
programmer to develop simple applications quickly. Despite these
benefits, large complicated programs, and programs that are more
dependent on speed still require the faster and relatively lower-
level languages with today's hardware. (The same concerns were
raised about the original Fortran language.)

History….
• Throughout the second half of the twentieth
century, programming was an attractive career in
most developed countries. Some forms of
programming have been increasingly subject to
offshore outsourcing (importing software and
services from other countries, usually at a lower
wage), making programming career decisions in
developed countries more complicated, while
increasing economic opportunities in less
developed areas. It is unclear how far this trend
will continue and how deeply it will impact
programmer wages and opportunities.

119321250-History-of-Computer-Programming.ppt

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