OLPC review now online, English too

The extensive OLPC article by c't magazine is now available online in both original German and an English translation. It's a thorough review (they had a B1 machine) with some interesting photographs in it, like the Squeak Etoys screen in reflective and backlight modes with microscopic images revealing the working of the XO's incredible LCD.

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Frontend-only Multi-Player. Unlimited Bandwidth. Or: What is Croquet.io, really?

A multi-player web app needs a backend, right? What if I told you, it doesn’t? Read on for how Croquet gets rid of servers running your multiplayer code. No, really . Instantaneous Shared Experiences is how we describe Croquet on our website. And while that excellently describes What Croquet does, as Croquet's Chief Architect, I wanted to share a bit about How we do that. So I wrote a Twitter thread . Here it is in blog form, slightly extended. Click the animation above if it does not play automatically Croquet lets you build completely client-side multi-user web apps. Read that again. Client-side. Multi-user. No I’m not kidding. I built it, I know it works. 😁 Croquet apps run completely client-side: are hosted as a static web site no server-side code needed no networking code needed Croquet is literally virtualizing the server: Instead of running code on a server (or in a serverless function) we run it as a virtual machine (VM) on each client. Croquet ca...

Deconstructing Floats: frexp() and ldexp() in JavaScript

While working on my SqueakJS VM, it became necessary to deconstruct floating point numbers into their mantissa and exponent parts, and assembling them again. Peeking into the C sources of the regular VM, I saw they use the frexp () and ldexp () functions found in the standard C math library. Unfortunately, JavaScript does not provide these two functions. But surely there must have been someone who needed these before me, right? Sure enough, a Google search came up with a few implementations. However, an hour later I was convinced none of them actually are fully equivalent to the C functions. They were imprecise, that is, deconstructing a float using frexp() and reconstructing it with ldexp() did not result in the original value. But that is the basic use case: for all float values, if [ mantissa , exponent ] = frexp (value) then value = ldexp ( mantissa , exponent ) even if the value is subnormal . None of the implementations (even the complex ones) re...

Smalltalk Bindings for Minecraft Pi

The Raspberry Pi is a cute little computer. Quite cheap at $35, you plug in USB keyboard+mouse and a TV as monitor. And it is surprisingly capable, even for running 3D games. One particularly interesting game is Minecraft: Pi Edition . As in other Minecraft versions, the main goal is to create a world. But unlike other versions, you can not only use the tools provided by the game, you can make your own tools! That's because it comes with a programming interface. The Minecaft world is made of little cubes, and you normally place or remove these blocks by hand, one after another. This is fun, but for larger structures also quite cumbersome. For example, this rainbow here might take a long time to construct manually: But I did not make the rainbow by hand. I programmed it, using the Smalltalk programming language. It's just these dozen lines of code in the Squeak programming environment: Squeak is already installed on the Raspberry Pi, because Scratch was made in Squea...

Dr. Vanessa Freudenberg

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