双语畅销书《艾伦图灵传》第5章:解谜接力赛(32)
日期:2018-02-07 10:05

(单词翻译:单击)

These were simply tables of all the core-positions, in which instead of printing 'has a female' or 'has no female', there would either be a hole punched, or not.
这是一套所有核位的卡片,上面并不是写着"有母鸡"或"无母鸡",而是靠是否打孔来区分。
In principle they could first have constructed one such huge table, and then each day could have made a template with the pattern of females observed in the traffic of that day.
理论上讲,他们可以事先构造一张巨大的表,然后再把当天的母鸡模式制成一张卡片。
Passing the template over the table, they would eventually have found a position where the holes matched.
拿着这张卡片,叠在核位大表上慢慢移动,与每个核位进行对比,最后就会找到一个核位,使它们所有的孔都匹配。
But that would have been far too inefficient a method.
但是,这个做法效率太低了。
Instead, they had a method of piling pieces of the table of core positions on top of each other, staggered in a manner corresponding to the observed relative positions of the females.
他们换了一种做法,把核位分成多张表格,全部重叠在一起,然后把它们按照某种方式错开(错开的方式取决于当天的母鸡模式),
A 'matching' of the pattern would then show up as a place where light passed through all the sheets.
这时能够透光的位置就是匹配的核位。
The advantage of this staggering system was that 676 possibilities could be examined simultaneously.
这种错开法的好处是,每次操作可以同时检查676个核位。
It was still a long job, requiring 6 × 26 operations for a complete search.
但这仍然是一项很耗时的工作,一次完整的查找,需要进行6×26次操作,
It also required the construction of perforated sheets listing the 6 × 17576 core-positions.
另外还需要代表6×17576个核位的打孔卡片。
Yet they achieved this within a few months.
不过,勤劳的波兰人只用了几个月,就成功地实现了这一切。
This was not the only method they devised. The perforated sheet system required the location of about ten females in the traffic.
这并不是他们设计的唯一方法。打孔卡片系统需要掌握大约10个母鸡的位置才能有效工作。
A second system required only three, but it used not only the mere existence of a female, but the particular letter that appeared as female in the cipher-text.
他们设计的另一种方法,只需要知道3个母鸡就可以了。但这种方法不仅利用母鸡的位置,还同时利用了作为母鸡的字母。
It was essential to the principle of the method that these particular letters had to be among those left unaffected by the plugboard.
这个方法还有一个限制:这些特定字母必须是不受配线板影响的。

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