Many Pies

Many Pies

Wednesday, December 18, 2013

Bitcoin - digging deeper and deeper into what it's all about

At the moment I'm finding Bitcoin really interesting.As you can tell from the post about Cryptography for Curious Kids I'm interested in cryptography. I've read overviews and that Wikipedia article I've linked to, and the Bitcoin wiki. I find that I grasp the overall concept. Then I read into the detail and think I've grasped it at a deeper level. Then I go away and forget about the detail and have more questions which means I need to read again, and deeper. Almost every fact seems to raise more questions. It's almost like an adventure game:

Bitcoin is a peer to peer digital currency. Where do you want to go?
N: How do they get created?
E: Can you have a physical Bitcoin?
S: What does it mean to have a quantity of them?
W: How do you exchange them for other currencies?

You have chosen S. The way that you have a Bitcoin is that everyone taking part in Bitcoin has a record of all the transactions that have taken place since they started being used, so everyone agrees that you have a certain number in your wallet.(OK not everyone taking part, but a lot of people.)

N: What is a wallet?
E: How does this information get synced between everyone?
S: What's to stop people falsifying the information?
W: How can you have fractional parts of a Bitcoin?

And so it goes on: mining, pooling, the blockchain, public/private keys, speculation about deflation, bubbles, anonymity, hashes, really big numbers.What's not to like?

Articles by my favourite bloggers (linking doesn't mean I agree)
I sold some Bitcoins by Tim Bray
Why I want Bitcoin to die in a fire by Charlie Stross

Tuesday, December 10, 2013

Publishing computer games

I was looking up in the loft for the paperwork I kept from when I was a teenager and sent in games for the ZX80, ZX81 and Spectrum to magazines. I didn't find that, but I found some other paperwork:
ZX81 ROM disassembly

A friend on Facebook found a copy of the Sinclair User Annual 1983 which had one of them in.

(Update: I called this game "Beancup" but I've just found out (Nov 2016) it's called Oware amongst other names.) I didn't always buy the magazines that published my games, because that would eat into the money I'd made, so it was quite exciting to see my work from so many years ago revived again. I didn't have a printer, so unlike many of the other listings this one was typeset.

Some things strike me about this:

  • no function names, you just GOSUB a line number
  • line numbers!
  • I'm surprised how compact it is - a two player game, plus the computer's strategy in just a few lines
Update: I was searching my blog archives for the word Sinclair and I came across this post about mobiles and gaming. What is interesting is the article I link to which talks about the potential for mobile (what we now call) apps. This was pre iPhone and Android app stores, so presents a "historical" perspective before things all changed.

Update (14 April 2023): while visiting my parents I found the original game which inspired me to write the program.