【正文】 difference engine in wood, after reading a brief description of Babbage’s project. 1834 Babbage conceives, and begins to design, his Analytical Engine. The program was stored on readonly memory, specifically in the form of punch cards. Babbage continues to work on the design for years, though after about 1840 the changes are minor. The machine would operate on 40digit numbers。 the mill (CPU) would have 2 main accumulators and some auxiliary ones for specific purposes, while the store (memory) would hold perhaps 100 more numbers. There would be several punch card readers, for both programs and data。 this scheme requires fewer relays than straight BCD. Rather than requiring users to e to the machine to use it, the calculator is provided with three remote keyboards, at various places in the building, in the form of teletypes. Only one can be used at a time, and the output is automatically displayed on the same one. In September 1940, a teletype is set up at a mathematical conference in Hanover, New Hampshire, with a connection to New York, and those attending the conference can use the machine remotely. 1941 Summer Atanasoff and Berry plete a specialpurpose calculator for solving systems of simultaneous linear equations, later called the ABC (AtanasoffBerry Computer). This has 60 50bit words of memory in the form of capacitors (with refresh circuits the first regenerative memory) mounted on two revolving drums. The clock speed is 60 Hz, and an addition takes 1 second. For secondary memory it uses punch cards, moved around by the user. The holes are not actually punched in the cards, but burned. The punch card system’s error rate is never reduced beyond %, and this isn’t really good enough. (Atanasoff will leave Iowa State after the US enters the war, and this will end his work on digital puting machines.) 1941 December Now working with limited backing from the DVL (German Aero nautical Research Institute), Zuse pletes the V3 (later Z3): the first operational programmable calculator. It works with floating point numbers having a 7bit exponent, 14bit mantissa (with a 1 bit automatically prefixed unless the number is 0), and a sign bit. The memory holds 64 of these words and therefore requires over 1400 relays。 with its small memory it is certainly not very useful on the equation solving problems that the DVL was mostly interested in. 1943 Computers between 1943 and 1959 (or thereabouts some say this era did not start until UNIVAC1 in 1951) usually regarded as ’first generation’ and are based on valves and wire circuits. The are characterised by the use of punched cards and vacuum valves. All programming was done in machine code. A typical machine of the era was UNIVAC, see 1951. 1943 I think there is a world market for maybe five puters., Thomas Watson, chairman of IBM. 1943 January The Harvard Mark I (originally ASCC Mark I, HarvardIBM Automatic Sequence Controlled Calculator) was built at Harvard University by Howard H. Aiken (19001973) and his team, partly financed by IBM it became the first program controlled calculator. The whole machine is 51 feet long, weighs 5 tons, and incorporates 750,000 parts. It used 3304 electromechanical relays as onoff switches, had 72 accumulators (each with it’s own arithmetic unit) as well as mechanical register with a capacity of 23 digits plus sign. The arithmetic is fixedpoint, with a plugboard setting determining the number of decimal places. I/O facilities include card readers, a card punch, paper tape readers, and typewriters. There are 60 sets of rotary switches, each of which can be used as a constant register sort of mechanical readonly memory. The program is read from one paper tape。 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。 Copyright 199620xx, Stephen White 500 . The abacus was first used by the Babylonians as an aid to simple arithmetic at sometime around this date. The abacus in the form we are most familiar with was first used in China in around 1300 . 1614 Scotsman John Napier (15501617) published a paper outlining his discovery of the logarithm. Napier also invented an ingenious system of moveable rods (referred to as Napier’s Rods or Napier’s bones). These allowed the operator to multiply, divide and calculate square and calculate cube roots by moving the rods around and placing them in specially constructed boards. 1623 Wilhelm Schickard (15921635), of Tuebingen, Wuerttemberg (now in Germany), made a Calculating Clock. This mechanical machine was capable of adding and subtracting up to 6 digit numbers, and warned of an overflow by ringing a bell. Operations were carried out by wheels, and a plete revolution of the units wheel incremented the tens wheel in much the same way counters on old cassette deck worked. The machine and plans were lost and fotten in the war that was going on, then rediscovered in 1935, only to be lost in war again, and then finally rediscovered in 1956 by the same man (Franz Hammer)! The machine was reconstructed in 1960, and found to be workable. Schickard was a friend of the astronomer Johannes Kepler since they met in the winter of 1617. 1625 William Oughtred (15751660) invented the slide rule. 1642 French mathematician, Blaise Pascal built a mechanical adding machine (the Pascaline). Despite being more limited than Schickard’s ’Calculating Clock’ (see 1623), Pascal’s machine became far more well known. He was able to se