The poor man's IBM

December 21, 2023

In Christina Thompson’s Sea People there is a very interesting anecdote about Yosihiko Sinoto, a japanese archaeologist that tried to figure out the chronology of the Hawaiian people by using their fishhooks.

…Sinoto sorted thousands of fishhooks to establish typologies— one-piece, two-piece, barbed, unbarbed, notched, knobbed. Sinoto even devised something he later described as a “poor man’s IBM”: a card file containing 3,500 entries, with either holes or slots cut into the top of each card. A metal rod inserted into the file would lift out only those cards with holes, leaving behind those with slots, thereby selecting a particular subset of the entries.

I find this fascinating. What kind of operations could be performed using a system as limited as this one?

If we imagine each card having several holes and slots, each one of them representing one bit of information we can perform the following filtering operations:

• AND: Insert the rod once, lift the cards out, and repeat this with a different feature.
• OR: Insert several rods to get the cards that have one or all of the features we want.
• NOT: Insert a rod to extract the feature we want filtered out. The cards that remain are the ones not having that particular feature.
• XOR: I’ll let you figure this one out.

I never thought a book about polynesian history would spark in me new ideas about computing!