I am generally all for not legislating anything, but the world really does need to use a commonly agreed system for physical measurements. That system is, like it or not, metric. Or rather SI units. I am sure I am not alone in thinking that some mistakes were made in the SI unit system —… Read More »
I’ve touched on the idea before, but I thought it was time I made it explicit. I want to compare customer-not-present purchases using bitcoins and using credit cards. In particular: security. Consider a modern web site, accepting a credit card. You fill up your basket and press “buyâ€. You have to supply: Name Address Email… Read More »
There’s a country where everybody wants to have a son. Therefore each couple keeps having children until they have a boy; then they stop. What fraction of the population is female? (You may assume the question is asked as an expectation of course, since any particular country can be anything in principle — 100% girls… Read More »
As we left things last time, we had a nicely organised dial plan that had the minimum of duplicated code, and was essentially a set of tables that mapped endpoints to extensions or queues. Let’s remind ourselves. [internal-extensions] ; Numeric aliases exten => 2100,1,Goto(andyp,1) exten => 2101,1,Goto(wife,1) exten => 2102,1,Goto(handytone1,1) exten => 2103,1,Goto(handytone2,1) exten =>… Read More »
Last time I showed you how to add voicemail facilities to your incoming lines. We concentrated on the local end, how a single access number could pickup voicemail from different mailboxes depending on the extension it was dialled from. I didn’t discuss the receiving side very much, and simply gave you this template: [external] exten… Read More »
I’ve heard lots about Tor, and thought it was about time I learned how to use it. I have no actual use for it; but in the same way I have no emails that are really private and yet still use OpenPGP, I like to know how to use the technology that keeps prying eyes… Read More »
On Radio 4’s PM some time ago, there was some guff talked about music quality. It’s standard guff talked by people who call themselves “audiophilesâ€, but in fact know absolutely nothing about electricity, signals, or in fact any mathematics whatsoever. They were very vague about it, but in essence the claim was that digital music… Read More »
I like to use avrdude for programming my AVR’s. It’s got support for pretty much every possible programming method supported by the AVR CPUs and has a good command line interface. A command line interface is very important when you use Makefiles to act as your IDE. Here, for example, is a little bit of… Read More »
This is the final part, part VI in my “Bitcoin Explained†series. Details then. Not necessarily relevant for understanding. Bitcoin’s transactions are a little more sophisticated than the paper analogy reveals. Each transaction is itself uniquely identified, and acts as a hub for transferring from any number of arbitrary sources to any number of arbitrary… Read More »
This is part V in my “Bitcoin Explained†series. At the end of part IV we saw how a signature chain can be used to create an unstealable ownership record; but that a dishonest person in the chain can easily create multiple copies of a valid signature chain. 17283726152 17283726152 I will pay the owner…… Read More »