Notes about Babbage
Babbage
Mathematician,
Engineer, Politician, Professor, Writer, Inventor, Cryptographer, Expert on
Industry, Socialite.
Preface: Tables of mathematical functions extremely important, especially
in Navigation, to engineers and governments. (Trig, Logs, Powers etc). Manual methods, handwritten and set in type
- laborious, error prone.
'Constant
differences' used to create these tables. (Explain)
1813-1814
as a student at Cambridge he thought of the idea.
Difference
Engine:
1823
- Received a grant of 1000 pounds from British Govt based upon his description
that was sent to the Royal Society of London which reached the Lords of the
Treasury. He hired a mechanical
engineer and started work. He and the
engineer had to redesign machine tools to achieve the degree of accuracy of machining
the parts that were needed. Planned to
print directly to metal plates.
1830
- More money advanced.
1832
- Small section of the engine completed.
24" x 19" x 14"
1834
- Problems with the engineer, all work ceased.
23,000
pounds spent: 17,000 Govt, 6,000 personal.
1842 - Officially canceled. If completed it was planned to be 2
tons; 10 ft x 10 ft x 5 ft.
Analytic
Engine:
1837ff Babbage drew plans for an all
purpose engine to do general problems more than just make tables. This would be similar to what we have in
computers today, would use punch cards for programming. The difference engine was only a calculator,
not programmed. Actual experimental
construction occurred after his death by his son.
Incorporated
the essential concepts of modern day programmed computers,
Sequence
Selection
- Compare and branch
Loops
Stored
program ? The punch cards kept the
programs
Machine tools still not
sophisticated enough. 1940, IBM
engineers used his plans and constructed a working model.