https://glaschick.de/rclab/ 2026-06-12T03:18:29+00:00 https://glaschick.de/rclab/ https://glaschick.de/rclab/lib/tpl/dokubook/images/favicon.ico text/html 2015-08-26T13:23:15+00:00 Anonymous (anonymous@undisclosed.example.com) https://glaschick.de/rclab/analyticalengine/bernoullinumbercalculation?do=revisions&rev=1440588195 Note G and the calculation of Bernoulli numbers See Bernoulli numbers in Wikipedia for details on Bernoulli numbers. They may have been selected as an example because: * They cannot be enumerated using the Difference Engine * The values seem to be fairly random text/html 2018-01-20T13:42:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://glaschick.de/rclab/analyticalengine/bernoullinumbers?do=revisions&rev=1516452120 Bernoulli numbers as examples Ada Lovelace had selected the calculation of Bernoulli numbers as the most advanced example in her notes to the description of the analytical engine. One outstanding feature of this example is the necessity to have indexed access to memory cells, because the calculation of the next number is a weighted sum of all previous ones (in the form used by A.L.). text/html 2015-10-22T22:33:58+00:00 Anonymous (anonymous@undisclosed.example.com) https://glaschick.de/rclab/analyticalengine/cardhandling?do=revisions&rev=1445546038 Card handling in the AE At least in the Sketch, the card handling is remarkably vague. As opposed to electronic computers, the many kinds of cards is astonishing, in particular, as there are no explanation on how their movement is coordinated. So far, these card types have been used: text/html 2015-08-20T13:47:58+00:00 Anonymous (anonymous@undisclosed.example.com) https://glaschick.de/rclab/analyticalengine/destructiveload?do=revisions&rev=1440071278 Destructive and retaining ingress operation When a number is transferred from the storage to the mill, the mechanism clears the number to zero (see Bromley 1998, p.31). In the sketch, it is mentioned at various places: * p. 677: When two numbers are to be combined together, the machine commences by effacing them from the columns where they are written, that is, it places zero on every disc of the two vertical lines on which the numbers were represented; and it transfers the numbers to the m… text/html 2015-10-22T22:35:27+00:00 Anonymous (anonymous@undisclosed.example.com) https://glaschick.de/rclab/analyticalengine/evolution?do=revisions&rev=1445546127 Evolution of the AE It is important to remember that, unlike the Difference Engines, the Analytical Engine was always a work in progress for Babbage. It was constantly evolving, sometimes dramatically so, as he had new ideas or found better ways to solve old problems, and since he was not actively trying to construct it, he was uninhibited in making large scale changes. text/html 2019-05-07T12:10:52+00:00 Anonymous (anonymous@undisclosed.example.com) https://glaschick.de/rclab/analyticalengine/inhalt?do=revisions&rev=1557223852 Die "Analytical Engine" Dieser Abschnitt enthält Betrachtungen über einen mechanischen Universalrechner, den Charles Babbage Mitte des 19. Jahrhunderts entworfen hat, um damit alle analytischen Funktionen berechnen zu können; und die er daher die text/html 2015-04-21T11:33:47+00:00 Anonymous (anonymous@undisclosed.example.com) https://glaschick.de/rclab/analyticalengine/isitaturingmachine?do=revisions&rev=1429608827 Is the AE Turing capable? In the section Note G and the calculation of Bernoulli numbers it is argued that the AE as designed at that time could not enumerate the Bernoulli numbers, at least not with the program given in the table of Note G and without register indexing. However, it is evident that the AE can easily simulate a text/html 2019-01-17T09:25:05+00:00 Anonymous (anonymous@undisclosed.example.com) https://glaschick.de/rclab/analyticalengine/lovelace_noteg_paper?do=revisions&rev=1547713505 Paper on Note G I have collected observations concering Note G and the AE in general, available for download: [Ada Lovelace's Calculation of Bernoulli's Numbers] Be warned, that it is rather detailled and nitpicking. Nevertheless, if you like it or like to comment, please drop me a note. For more notes on the AE, see the text/html 2015-11-29T10:55:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://glaschick.de/rclab/analyticalengine/retaingreadcell?do=revisions&rev=1448790911 Memory Cell with Reataining Readout Babbage's memory cell in the storage used a reduction-to-zero technique, so it was necessary to restore the values for a retaining read. In some designs, he even used a second cell to temporarily save the last value. text/html 2016-06-08T09:22:31+00:00 Anonymous (anonymous@undisclosed.example.com) https://glaschick.de/rclab/analyticalengine/typos?do=revisions&rev=1465370551 Typographical Errors and Hints The Sketch of the Analytical Enigine.. uses some typgraphical conventions not common today, and there are a few apparent typographical errors. It is available as a facsimile unter archive.org (processed version removing the background: text/html 2016-03-08T16:39:22+00:00 Anonymous (anonymous@undisclosed.example.com) https://glaschick.de/rclab/analyticalengine/visualae?do=revisions&rev=1457451562 Game-like Visualisation of the AE In the exposition Am Anfang war Ada. Frauen in der Computergeschichte (open till July, 10 2016, Heinz Nixdorf MuseumsForum, Paderborn, Germany), there is an application to give the visitor an impression about the AE. text/html 2019-01-15T14:38:04+00:00 Anonymous (anonymous@undisclosed.example.com) https://glaschick.de/rclab/analyticalengine/weblinks?do=revisions&rev=1547559484 References und Links Die folgenden Literatur- und WEB-Verweise sind eine subjektive Auswahl: Dorothy Stein: Ada: a life and legacy. The MIT Press, Cambridge MA und London, 1985. ISBN 0-262-19242-X. Betty Alexandra Toole: Ada, the Enchantress of Numbers, Prophet of the Computer Age text/html 2015-06-01T10:47:15+00:00 Anonymous (anonymous@undisclosed.example.com) https://glaschick.de/rclab/analyticalengine/whichcomplement?do=revisions&rev=1433148435 Two Zeros Allan Bromley (The Programmer's Interface, IEEE Annals, Oct-Dec 2000, p.12r, Ascertaining..) writes: " There as thus two zero values, ±0, that can be represented separately and will produce different results when the sign is tested. There is no clear evidence that the microprograms attempted systematically to map -0 to +0 although multiplication does so by default. text/html 2015-04-22T22:19:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://glaschick.de/rclab/analyticalengine/zeroingtemporaries?do=revisions&rev=1429733940 Zeroing Working Variables Nobody programming today would consider it, but AAL wrote on p. 708: " At the end of a calculation, therefore, every column ought as a general rule to be zero, excepting those for results." That's why I think a zero is missing in line 24 column V