| |
KF5JRV > TECH 23.06.16 12:54l 111 Lines 5457 Bytes #999 (0) @ WW
BID : 4962_KF5JRV
Read: GUEST
Subj: Steam Computer
Path: IW8PGT<HB9CSR<IK2XDE<F1OYP<ON0AR<VK6HGR<ZL2BAU<N0KFQ<KF5JRV
Sent: 160623/1131Z 4962@KF5JRV.#NWAR.AR.USA.NA BPQK1.4.65
Steam powered Computer
In the 1821 vignette of Babbage and his friend, the astronomer,
John Herschel, checking manually calculated tables, Babbage,
finding error after error, was driven to exclaim 'I wish to God
these calculations had been executed by steam'. The grindingly
tedious labor of manually checking tables was one thing. Worse
was their unreliability. Babbage embarked on an ambitious
venture to design and build mechanical calculating engines - vast
machines of unprecedented size and intricacy - to eliminate
the risk of human error. The infallibility of machinery would
eliminate the risk of error from calculation and transcription
(copying the results). Automatic typesetting would banish the
risk of error when manually setting results in loose type.
Stereotyping - a process that automatically impressed results
on soft material for the manufacture of printing plates - would
eliminate errors in repeated printing. Special security
devices would ensure the integrity of the results. The outcome
would be flawless. This was the intention, but one that he failed
to realize.
Difference Engine No. 1 - A Fateful Start
His first machine, Difference Engine No. 1, was designed to
automatically calculate and tabulate mathematical functions
called polynomials which have powerful general applications
in mathematics and engineering. Babbage worked closely with
Joseph Clement, a master toolmaker and draftsman who was tasked
with making the parts. Difference Engine No. 1 called for
25,000 parts and would have weighed an estimated four tons.
Construction was abruptly halted in 1833 when Clement downed
tools and fired his workmen following a dispute with Babbage
over compensation for moving Clement's workshop closer to
Babbage's house. The Engine was never built. Some 12,000
unused precision parts were later melted down for scrap.
For the British Government that had bankrolled the venture,
the project was a costly failure. When the final bills were
paid the Treasury had spent 17,500 - the cost of twenty-two
brand new steam locomotives from Robert Stephenson's factory
in 1831 - a formidable sum.
The Finished Portion of the Unfinished Engine
A small demonstration assembly was built and delivered to
Babbage by Clement in 1832. This 'beautiful fragment', one
seventh of the calculating section, was all Babbage had to
show after a decade of investment. Babbage used the piece to
develop his ideas on computation and also for dramatic
demonstrations to savants, guests, dignitaries, scientists,
and friends. The device proved the soundness of the design
and supported the feasibility of a full machine. It was the
first successful automatic calculator and one of the finest
examples of precision engineering of the time. It remains
amongst the most celebrated icons in the prehistory of
automatic computation.
The Analytical Engine
In 1834, with the Difference Engine project stalled, Babbage
conceived of a new more ambitious machine, later called the
Analytical Engine - a general-purpose programmable computing
machine. The Analytical Engine was a quantum leap in logical
conception and physical size, and its design ranks as one of
the startling intellectual achievements of the century.
The Analytical Engine features many essential principles found
in the modern digital computer and its conception marks the
transition from mechanized arithmetic to fully-fledged general
purpose computation. Had the Engine been built, it would have
dwarfed even the vast Difference Engine and cranking it by hand
would have been beyond the strongest operator. 'Calculating by
steam' would have been more than a figure of speech. It is on
the Analytical Engine that Babbage's standing as 'the first
computer pioneer' largely rests.
The Second Difference Engine
As Babbage refined the mechanisms of the Analytical Engine he saw
how he could simplify the design of the Difference Engine. Between
1847 and 1849 he designed a new engine, Difference Engine No. 2.
The new design benefited from many of the techniques developed
for the more demanding Analytical Engine.
The new design was elegant and efficient requiring one third the
number of parts of Difference Engine No. 1 for greater computing
power. With 8,000 parts, the Engine would weigh five tons and
measure eleven feet long and seven feet high. Babbage made no
attempt to construct the machine. It is this design that was
finally built and completed in 2002, and is the first of
Babbage's engine designs to be realized in its entirety.
Two Inspired Swedes
Others attempted to build difference engines in Babbage's time,
all with dismal outcomes. Inspired by an account of Babbage's
first engine, published in 1834, a Swedish father-and-son team,
Georg and Edvard Scheutz, built a working prototype, completed
in 1843. Two fully engineered versions in metal followed, the
first in 1853 in Stockholm, the second in 1859 in London for
the General Register Office.
Neither was much of a success. The hoped-for economies of
automatic tabulation by machinery did not materialize.
Worse still, the machine, made in London, lacked Babbage's
security devices, tended to derangement, and required
constant care. Both father and son died bankrupt. Building
difference engines contributed to their ruin. The three
engines now reside in museums, handsome testaments to
dashed hopes and financial disaster.
Read previous mail | Read next mail
| |
