【正文】 addition in 3 seconds and a multiplication or division in 24 minutes. 1842 Babbage’s difference engine project is officially cancelled. (The cost overruns have been considerable, and Babbage is spending too much time on redesigning the Analytical Engine.) 1843 Scheutz and his son Edvard Scheutz produce a 3rdorder difference engine with printer, and the Swedish government agrees to fund their next development. 1847 Babbage designs an improved, simpler difference engine, a project which took 2 years. The machine could operate on 7thorder differences and 31digit numbers, but nobody is interested in paying to have it built. (In 198991, however, a team at London’s Science Museum will do just that. They will use ponents of modern construction, but with tolerances no better than Clement could have provided... and, after a bit of tinkering and detaildebugging, they will find that the machine does indeed work.) 1848 British Mathematician Gee Boole devised binary algebra (Boolean algebra) paving the way for the development of a binary puter almost a century later. See 1939. 1853 To Babbage’s delight, the Scheutzes plete the first fullscale difference engine, which they call a Tabulating Machine. It operates on 15digit numbers and 4thorder differences, and produces printed output as Babbage’s would have. A second machine is later built to the same design by the firm of Brian Donkin of London. 1858 The first Tabulating Machine (see 1853) is bought by the Dudley Observatory in Albany, New York, and the second one by the British government. The Albany machine is used to produce a set of astronomical tables。 but the observatory’s director is then fired for this extravagant purchase, and the machine is never seriously used again, eventually ending up in a museum. The second machine, however, has a long and useful life. 1871 Babbage produces a prototype section of the Analytical Engine’s mill and printer. 1878 Ramon Verea, living in New York City, invents a calculator with an internal multiplication table。 this is much faster than the shifting carriage or other digital methods. He isn’t interested in putting it into production。 he just wants to show that a Spaniard can invent as well as an American. 1879 A mittee investigates the feasibility of pleting the Analytical Engine and concludes that it is impossible now that Babbage is dead. The project is then largely fotten, though Howard Aiken is a notable exception. 1885 A multiplying calculator more pact than the Arithmometer enters mass production. The design is the independent, and more or less simultaneous, invention of Frank S. Baldwin, of the United States, and T. Odhner, a Swede living in Russia. The fluted drums are replaced by a variabletoothed gear design: a disk with radial pegs that can be made to protrude or retract from it. 1886 Dorr E. Felt (18621930), of Chicago, makes his Comptometer. This is the first calculator where the operands are entered merely by pressing keys rather than having to be, for example, dialled in. It is feasible because of Felt’s invention of a carry mechanism fast enough to act while the keys return from being pressed. 1889 Felt invents the first printing desk calculator. 1890 1890 . census. The 1880 census took 7 years to plete since all processing was done by hand off of journal sheets. The increasing population suggested that by the 1890 census the data processing would take longer than the 10 years before the next census so a petition was held to try to find a better method. This was won by a Census Department employee, Herman Hollerith who went on to found the Tabulating Machine Company (see 1911), later to bee IBM. Herman borrowed Babbage’s idea of using the punched cards (see 1801) from the textile industry for the data storage. This method was used in the 1890 census, the result (62,622,250 people) was released in just 6 weeks! This storage allowed much more indepth analysis of the data and so, despite being more efficient, the 1890 census cost about double (actually 198%) that of the 1880 census. 1892 William S. Burroughs (18571898), of St. Louis, invents a machine similar to Felt’s (see 1886) but more robust, and this is the one that really starts the mechanical office calculator industry. 1896 IBM founded (as the Tabulating Machine Company), see 1924. Founded by Herman Hollerith (18601929, see also 1890). 1899 Everything that can be invented has already been invented., Charles H. Duell, director of the . Patent Office 1906 Henry Babbage, Charles’s son, with the help of the firm of R. W. Munro, pletes the mill of his father’s Analytical Engine, just to show that it would have worked. It does. The plete machine is never produced. 1906 Electronic Tube (or Electronic Valve) developed by Lee De Forest in America. Before this it would have been impossible to make digital electronic puters. 1911 Merger of panies, including Herman Hollerith’s Tabulating Machine Company, to Computing Tabulating Recording Company which became IBM in 1924. 1919 W. H. Eccles and F. W. Jordan publish the first flipflop circuit design. 1924 February International Business Machines (IBM corporation) formed after more mergers involving the Computing Tabulating Recording Company see 1911. By 1990 IBM had an ine of around $69 Billion (and 373,816 employees), although in 1992 recession caused a cut in stock dividends (for the first time in the pany’s history) and the sacking of 40,000 employees. 19311932 E. WynnWilliams, at Cambridge, England, uses thyratron tubes to construct a binary digital counter for use in connection with physics experiments. 1935 International Business Machines introduces the IBM 601, a punch card machine with an arithmetic unit based on relays and capable of do