双语畅销书《艾伦图灵传》第7章:运转起来(69)
日期:2019-01-30 19:36

(单词翻译:单击)

After working on a 'Difference Engine', to mechanise the particular numerical method used in the construction of mathematical tables, Babbage had conceived (by 1837) of an Analytical Engine, whose essential property was that of mechanising any mathematical operation.
巴贝奇在研究差分机的基础上,为了将构造数学表的过程机械化,构想了一种分析引擎,其基本特性就是能够机械地执行任何数学运算。
It embodied the crucial idea of replacing the engineering of different machines for different tasks, by the office work of producing new instructions for the same machine.
这就体现了在做不同的工作时,可以通过设计新的指令,而不是设计新的设备,这是非常重要的思想。
Babbage did not have a theory like that of Computable Numbers, to argue for universality, and his attention was focussed upon operations using numbers in decimal notation.
巴贝奇没有《可计算数》这样的理论来证明其通用性,他的注意力集中在十进制的数值运算,但他也确信这种机制可以执行任何符号运算注。
Yet he did perceive that its mechanism could serve to effect operations upon symbols of any kind whatever, and in this and other ways the Analytical Engine came close in its conception to the Universal Turing Machine.
分析引擎和通用图灵机,在很多方面都有相似之处。
Babbage wanted a 'scanner', in effect, working on a stream of instructions, and putting them into operation.
巴贝奇也需要一个"扫描器",在一串指令上来回操作。
He hit on the idea of coding the instructions on punched cards, such as then were used for the weaving of complicated patterns in brocade.
他想到了把指令做成打孔卡片,从而使织机可以自动在锦缎上织出复杂的图案。
His plans also called for storing numbers in the form of positions of gear wheels. Each instruction card would cause an arithmetical operation such as 'subtract the number in location 5 from that in location 8, and put the result in location 16.'
他还打算用齿轮的位置来存储数值。每一张指令卡片会执行一次算术操作,比如"用5号位置的数减去8号位置的数,并将结果存到16号位置"。
This required machinery he called the 'mill' to do the arithmetical operations, but the crucial innovation of Babbage's plans did not lie in the efficient mechanisation of adding and multiplying.
他把执行算术运算的部件称为"作坊"。但是,巴贝奇计划的重要创新之处,并不在于机械运算,
It lay in his perception that it was the mechanisation of the organising or logical control of the arithmetic that mattered.
而是在于他发现了,对算术过程的组织和逻辑控制才是最重要的。
In particular, Babbage had the vital idea that it must be possible to move forwards or backwards among the stream of instruction cards, skipping or repeating, according to criteria which were to be tested by the machine itself in the course of its calculation.
特别是,巴贝奇有一个关键的想法是,机器必须能够在一串指令卡片中来回遍历,并根据实际计算的情况,来决定跳过或重复。
This idea, that of 'conditional branching', was his most advanced.
这种"条件分支"的想法,是他最先进的地方。
It was equivalent to the freedom allowed to Turing machines, that of changing 'configuration' according to what was read on the tape, and it was this that made Babbage's planned machine a universal one, as he himself was well aware.
而这种自主性,与图灵机是等价的,图灵机就是根据纸带上的指令来切换机器的状态。巴贝奇很清楚,正是这一点,使他的机器具有通用的特性。

分享到