雙語暢銷書《艾倫圖靈傳》第8章:水銀延時線(11)
Thus a problem might easily need a storage of three million entries, and if each entry was equally likely to be the next required the average journey up the tape would be through a million entries, and this would be intolerable.
One needs some form of memory with which any required entry can be reached at short notice.
我們需要一種存儲形式，能夠在很短的時間內訪問到需要的存儲項。This difficulty presumably used to worry the Egyptians when their books were written on papyrus scrolls.
這個困難，也許常常使古埃及人感到苦惱，因爲他們總在沙草紙捲上書寫，
It must have been slow work looking up references in them, and the present arrangement of written matter in books which can be opened at any point is greatly to be preferred.
要檢索某個特定的內容是非常耗時的。而我們現在使用的書本，可以快速打開其中的一頁。We may say that storage on tape and papyrus scrolls is somewhat inaccessible. It takes a considerable time to find a given entry.
我們可以說，紙帶或埃及紙卷這樣的存儲，是"不可讀取的"，因爲它們需要消耗大量的時間，才能找到一個特定的項目。Memory in book form is a good deal better, and is certainly highly suitable when it is to be read by the human eye.
書本這種形式，就是相對更好的方案，更適合人類閱讀。We could even imagine a computing machine that was made to work with a memory based on books.
我們甚至可以想象一臺以書本作爲存儲器的機器，It would not be very easy but would be immensely preferable to the single long tape.
雖然這種方案存在很多困難，但至少比一條長紙帶要好。Let us for the sake of argument suppose that the difficulties involved in using books as memory were overcome, that is to say that mechanical devices for finding the right book and opening it at the right page, etc. etc. had been developed, imitating the use of human hands and eyes.
爲了討論這個問題，我們不妨假設有一種機器裝置，能夠模仿人類的眼睛和手，找到正確的書，並翻到正確的那一頁。The information contained in the books would still be rather inaccessible because of the time occupied in the mechanical motions.
但即便如此，書裏的信息仍然是不可讀取的"，因爲翻書所需的機械運動，仍然要消耗很長時間。One cannot turn a page over very quickly without tearing it, and if one were to do much book transportation, and do it fast, the energy involved would be very great.
翻得太快，會把書撕壞，而且要想快速地移動書本，則要消耗大量的能量。Thus if we moved one book every millisecond and each were moved ten metres and weighed 200 grams, and if the kinetic energy were wasted each time, we should consume 1010 watts, about half the country's power consumption.
假如我們需要每毫秒將一本200克的書移動10米，而且其動能沒有其它作用的話，那麼該機器的能耗大約是1010瓦，相當於全國能耗總量的一半。If we are to have a really fast machine then we must have our information, or at any rate a part of it, in a more accessible form than can be obtained with books.
所以，如果我們想構造一臺高速的機器，就必須有一種更合理的存儲機制，而不是書本。
