Other computer company firsts When was the word "computer" was first used? The word "computer" was first recorded as being used in and originally was used to describe a human who performed calculations or computations. The definition of a computer remained the same until the end of the 19th century, when the industrial revolution gave rise to machines whose primary purpose was calculating.
The process of adding letters together is explained in the next paragraph. The internal mechanism of the Tunny machine produced its own stream of letters, known at B. Each letter of the ciphertext was produced by adding a letter from the key-stream to the corresponding letter of the plaintext.
The Tunny machine adds letters by adding the individual dots and crosses that compose them. The rules that the makers of the machine selected for dot-and-cross addition are simple.
Dot plus dot is dot.
Cross plus cross is dot. Dot plus cross is cross. Cross plus dot is cross.
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In short, adding two sames produces dot, and adding a mixed pair produces cross. Computer literati will recognise Tunny addition as boolean XOR. For example, if the first letter of the plaintext happens to be M, and the first letter of the key-stream happens to be N, then the first letter of the ciphertext is T: The German engineers selected these rules for dot-and-cross addition so that the following is always true no matter which letters, or other keyboard characters, are involved: For example, adding N to M produces T, as we have just seen, and then adding N to T leads back to M see right-hand column.
Flowers, creator of Colossus. The Tunny at the receiving end adds the same letters of key to the encrypted message: Wheels 1—5 are the psi-wheels, wheels 6 and 7 are the motor-wheels, and wheels 8—12 are the chi-wheels.
The Battle of Kursk was a turning point of the war. The Tunny machine in fact produces the key-stream by adding together two other letter streams, called at B.
The psi-stream and the chi-stream are produced by the wheels of the Tunny machine. Let us consider the wheels in more detail. The twelve wheels form three groups: The function of the cam is to push a switch as it passes it, so that as the wheel rotates a stream of electrical pulses is generated.
The operator can adjust the cams, sliding any that he selects sideways, so that they become inoperative and no longer push the switch when they pass it see right-hand column.
The wheel now causes not a uniform stream of pulses as it turns, but a pattern of pulses and non-pulses—crosses and dots. The arrangement of the cams around the wheel, operative or inoperative, is called the wheel pattern. Prior to the summer of the Germans changed the cam patterns of the chi-wheels once every month and the cam patterns of the psi-wheels at first quarterly, then monthly from October After 1 Augustwheel patterns changed daily.
The changes were made according to books of wheel patterns issued to Tunny units different links used different books.Cool Genome Sequencing Sites To see the pioneers of genomic sequencing check out The Institute for Genomic Research and their private affiliate Human Genome ashio-midori.comces for Haemophilus influenzae, Mycoplasma Genitalium, Methanococcus jannaschii, Archaeoglobus fulgidus, Helicobacter pylori, and Borrelia burgdorferi can be found at the TIGR site along with links to their papers.
There are many people out there who would say that the first "computer" was the abacus, invented in Asia about years ago. But somehow I doubt that this is what you're looking for, so let's look a little more recently. The first analog computer invented was the Antikythera Mechanism, about years ago.
One sample was found in an ancient shipwreck about It was designed to calculate a stronomical positions for navigation. AT A GLANCE: Daniel Hess appears to have been the first to patent (#29, U.S.
issued July 10, ) a vacuum cleaner. Hess, a resident of West Union, Iowa, called his invention a . This document gives a chronology of computing at Columbia University, as best I can piece it together, written mainly in Jan-Feb , updated periodically since then (time of last update listed above).
- History of Computers Historically, the most important early computing instrument is the abacus, which has been known and widely used for more than 2, years. Another computing instrument, the astrolabe, was also in use .