
Inside card sorters: 1920s data processing, relay logic and linear time sorting - kens
http://www.righto.com/2016/05/inside-card-sorters-1920s-data.html
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Animats
Card sorters are not linear time. They're number of cards x number of columns
of sort key. Sort keys, if unique, have to have size O(log N), so card sorters
are O(N log N), as you'd expect.

You can beat O(N log N) with a radix-like sort (SyncSort, the first software
patent, shows how), but you need more bins than a card sorter has.

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GnarfGnarf
If you have 1,000 cards and you are sorting on 6 columns, you have to pass all
the cards 6 times, which means reading 6,000 cards. Is this O(N log N)?

I know this because I did it for a living when I started working in 1970.

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FroshKiller
If you're interested in tabulators & punch cards and the impact they had on
human history, read IBM and the Holocaust by Edwin Black. It's a sometimes dry
but fascinating explication of the role IBM played in supporting the Holocaust
and the strategies the company employed to continue doing business with
Germany during the war.

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raddad
>tabulators & punch cards and the impact they had on human history

I think everyone in school came home with a Christmas wreath made out of punch
cards. Every now and then I still see cases of punch cards offered for free.

Here is an example of a wreath:

[http://www.computerhistory.org/collections/catalog/102667304](http://www.computerhistory.org/collections/catalog/102667304)

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weinzierl
If you also wondered about the "linear time sorting" part.

Punch card sorters used an electro-mechanical (even without vacuum tubes)
implementation of radix sort.

