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Dijkstra thought about the shortest path problem when working at the Mathematical Center in Amsterdam in 1956 as a programmer to demonstrate the capabilities of a new computer called ARMAC(below.?.. ). His objective was to choose both a problem as well as an answer (that would be produced by computer) that non-computing people could understand. He designed the shortest path algorithm and later implemented it for ARMAC for a slightly simplified transportation map of 64 cities in the Netherlands (64, so that 6 bits would be sufficient to encode the city number)当時、64都市!?, 程度の「最短経路問題 」をけいさんするには 6bits 程度の・ものでじゅうぶんだった. //・・現在は、どんな学生?でも?!, このくらい?のアルゴリズム計算は、(手計算)？・で　^20分? でむましてしまう・そうである ??? . A year later, he came across another problem from hardware engineers working on the institute's設計-製作?? next computer: minimize the amount of wire needed to connect the pins on the back panel of the machine. As a solution, he re-discovered the algorithm known as Prim's minimal spanning tree algorithm (known earlier to Jarnik, and also rediscovered by Prim). Dijkstra published the algorithm in 1959, two years after Prim and 29 years after Jarnik.「プリム法. 」(グラフ理論で重み付き連結グラフの最小全域木を求める最適化問題のアルゴリズムである. 「全域木 」（対象となるグラフの全頂点を含む辺の部分集合で構成される木）のうち、その辺群の重みの総和が最小となる木を求めるものである. このアルゴリズムは1930年に数学者 Vojt?ch Jarnik が発見し、1957年に計算機科学者ロバート・C・プリムが独自に発見、さらに1959年にはエドガー・ダイクストラが再発見しダイクストラ法の論文に記載している. そのため、DJP法、Jarnik法、Prim-Jarnik法などとも呼ばれることがある. アルゴリズムの発想や計算量は同時期に発表されたダイクストラ法に類似している・・・ ・・アルゴリズムが進歩する・たびに??, 'computerｓ'-machines? は小型化していった（よけいな計算!?, わかりきった-定式化された計算 etc?.. など？・はすべて'computer's programmings '(ソフトウェア部門?!? がうけもつことに・なるだろう ?!.?!?,!? ) ）)
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<The ARMAC at the Mathematical Center >
The ARMAC, (Automatische Rekenmachine van het Mathematisch Centrum, translated: Automatic Computing machine of the Mathematica Center), was built as a successor of the ARRA II and is only used internally at the Mathematical Center. This computing machine was much more complex than the sequential ARRA, ARRA II and FERTA. The ARMAC was a parallel computer, meaning it did not need multiple clock ticks for addition of two numbers.

Scholten and Loopstra were responsible for the design and physically building the ARMAC. Programming of the ARMAC is performed by E.W. Dijkstra. Building the ARMAC took around 1.5 years. In this period Blaauw left the Mathematical Center and joined IBM. In 1956 the computing machine ARMAC was ready for usage.(アルゴリズムのたんじょう?・・) The ARMAC is also the last computing machine built at the Mathematical Center. The Mathematical Center stopped its computer building activities, but started a independent spin-off company, Electrologica N.V.

Technical Details
The ARMAC consisted of two types of memory: old drum memory, like used in the ARRA II, and the newer, faster magnetic memory. The magnetic memory was used to buffer a track of the '''drum memory""(磁気ドラムメモリは1950年代から1960年代にかけて、コンピュータの記憶装置として広く使われた・・,・ 性能を向上させるため、プログラマはコードの配置を慎重かつ緻密に計算した. ある命令を実行して次の命令を実行するために磁気ドラムメモリから読もうとしたときにちょうどその命令が磁気ヘッドの位置に来るよう計算したのである. これによりドラムの回転を待たずに次々と命令を実行できるようにした. この方式は後にセクタ-インターリーブ(キーボードの配列が・アルファベット順になっていないようなもの ??, )として、フロッピーディスクやハードディスクのセクタ配置最適化に応用されている. <最適化ーー磁気ドラムメモリ（Magnetic Drum Memory ）>). Instructions available in that buffer were accessible faster. The drum memory of the ARMAC consisted of 3584 words. Each word consisted of 34bits, meaning 33 data bits and 1 parity bit. A clock pulse took 13.3 milliseconds. The magnetic memory consisted of two times 32 words. A clock pulse for this memory took 20 microseconds.
(えいごは、26文字?!, computer にとっては・・さいてきの言語　！！？ )
The buffered memory design imposes sequential addressing performed by the programmer. This was one of the reasons for Dijkstra to illustrate methods of structured programming. To show the power of the ARMAC, Dijkstra implemented one of his most famous algorithms, the shortest path algorithmもっとの有名な「最短経路問題 !!!,」, on it.

The ARMAC had two computing registers. The opcodes[=? operation codes ] used 5 bits and addresses[computer's address!? ] took 12 bits. Furthermore it was possible to use subroutine jumps, by using a link in a register. The computing machine consisted of 1200 tubes and consumed around 10 kilo Watt.(あまりにも?・でんき^ いりすぎ ?,?? )

Since computing machines in those years made a lot of noise, it was a tradition at the Mathematical Center to beep the Dutch national anthem(ナショナルアンセム、国歌(をよびだす?/ いまの Windows のたちあがりのさいの・呼び出し音の・もと ???, ), Wilhelmus using the ARMAC whenever a royalty would visit the Mathematical Centerさんじゅつセンター?? .

Performance
For some computations, the ARMAC was 50 times as fast as the ARRA II. Addition, subtraction and multiplication were standard routines in the instruction set of the ARMAC. In drum memory, a sub-routine was available to divide. Since division was very slow, most programmers decided to multiply with the inverse instead of performing a division. To illustrate the performance of the ARMAC:
Addition and subtraction of two numbers took 416 microseconds.(+, - にいがいと時間が??,・ )
Multiplication of two numbers took 5.4 milliseconds.
Moving a track of 32 words took 14.6 milliseconds.

How fast the ARMAC was for real computational work is a little subjective, since Loopstra claimed an average speed of 1000 instructions per second and Dijkstra claimed an average of 2400 instructions命令['computerｓ' にたいする指令? のようなもの??, ] per second.
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(組立て・構築??に１年半、 programming は、ダイクストラとIBM's staff があたった. ドイツにおいて研究がスタートし、・オランダにて・はじめて Centrum Wiskunde & Informatica (abbr. CWI; English: "National Research Institute for Mathematics and Computer Science") が設立された. ... その後、理由?,があってアメリカにいどう？・！,・ 　　ふるい、・・'computerｓ'は書棚の・ようだった ???, )