雙語暢銷書《艾倫圖靈傳》第8章:水銀延時線(22)
It was an idea that had arrived somewhat by chance.
On the American side, they had thought of storing instructions internally because it was the only way of supplying instructions quickly enough.
對美國方面來說，他們之所以能想到內部存儲指令，是因爲這是快速供應指令的唯一方法。On the Turing side, he had simply taken over the single tape of the old Universal Turing Machine.
而對於圖靈來說，這只不過是很自然地延續了通用圖靈機的單一紙帶。
But neither of these reasons for adopting stored instructions said anything about the possibility of interfering with the instructions in the course of a computation.
但是，這兩種不同的理由，都沒有涉及一種新的可能，也就是指令可以在計算過程中進行改變。On the American side, it was not pointed out as a feature of the new design until 1947.
美國方面直到1947年，才考慮到這個新特性。Equally, the Universal Turing Machine, in its paper operation, was not designed to change the 'description number' that it worked upon.
同樣，通用圖靈機在紙上操作時，也不能改變正在執行的描述數，It was designed to read, decode, and execute the instruction table stored upon its tape.
它只能取出、識別和執行存儲在紙帶上的指令，It would never change these instructions.
這樣的設計永遠不能使指令發生改變。The Universal Turing Machine of 1936 was like the Babbage machine in the way that it would operate with a fixed stock of instructions.
1936年的通用圖靈機，只能操作固定存儲的指令，這點與巴貝奇機是一樣的。(It differed in that that stock was stored in exactly the same medium as the working and the input and output.)
（不同的是，圖靈機的指令存儲、工作空間、輸入和輸出，都在同一介質上。）And so Alan Turing's own 'universality' argument showed that a Babbage-like machine was enough.
根據圖靈關於通用性的觀點，一個類似巴貝奇機的機器就已經足夠了，In principle there was nothing that could be achieved through modifying the instructions in the course of an operation that could not be achieved by a universal machine without this facility.
在運行過程中改變自己的指令，是個多餘的特性。The faculty of program modification could only economise on instructions, and would not enlarge upon the theoretical scope of operations.
這種特性只是能夠節省指令，無法帶來什麼新的功能。But that economy could, as Alan said, be 'Very powerful'.
不過，正如圖靈所說，經濟性也是"非常重要"的。
