Bitcoin mining on a 55 year old IBM 1401 mainframe: 80 seconds per hash


Ken Shirriff writes:

Could an IBM mainframe from the 1960s mine Bitcoin? The idea seemed crazy, so I decided to find out. I implemented the Bitcoin hash algorithm in assembly code for the IBM 1401 and tested it on a working vintage mainframe. It turns out that this computer could mine, but so slowly it would take more than the lifetime of the universe to successfully mine a block. While modern hardware can compute billions of hashes per second, the 1401 takes 80 seconds to compute a single hash. This illustrates the improvement of computer performance in the past decades, most famously described by Moore’s Law.

Details at┬áKen’s blog.

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  1. Hi,

    ‘Moore’s Law’ stated that the density of transistors on an integrated circuit would double every two years. It did not say anything specifically about computer performance improvements, although a case can be made that you can’t have one without the other.


  2. So, instead he should have said “House’s Corollary to Moore’s Law states that *performance* will double roughly every 18 months.” instead… :P

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