Mining like it's 1959

Thursday 28 May 2015

Sure you can mine bitcoins on the latest ASIC. But you can also use a 50-year-old mainframe. Kind of.

Here’s a blog post that’s worth a look. Ken Shirriff, microprocessor enthusiast, has pimped an IBM 1401 mainframe to mine bitcoins.

Read also: Spotlight on hash rate

It’s not true: you can teach an old dog new tricks. Admittedly, the 1401 isn’t quite up to the speed of the latest ASIC chips. Whilst these will manage several TH/s (terahashes per second, or million, million hashes), the 1401 can handle one hash every 80 seconds - meaning a good ASIC will have crunched through a hundred thousand billion hashes before the 1401 has got out of bed in the morning and notched up its first sum.


The IBM 1401: a bit of a dinosaur, but quite effective in its day

Actually, it’s pretty incredible that such an old computer can even be convinced to do the job. It was aimed at small businesses, cost $2,500 (over $20,000 in today’s money) and could be used with both magnetic tape and punched cards. ‘I implemented the Bitcoin hash algorithm in assembly code for the IBM 1401 and tested it on a working vintage mainframe,’ writes Shirriff. ‘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.’

It will sadly take Ken until the heat death of the universe to mine a block with his 1401. On the other hand, given how far computers have come in the last 50 years, the fastest ASIC will probably be little more than a retro paperweight in a few years’ time. Still, it’s a worthy undertaking, and a labour of love to introduce an old workhorse from the 1960s to the cutting edge of 21st century cryptography. If we were all still using these, ever-increasing Difficulty would become a thing of the past.

And, as it happens, using the IBM mainframe is a lot faster than doing it by hand. Ken knows, because he’s tried that too

Brandon Hurst

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