Luca's meaningless thoughts  

TED: Witricity

by Leandro Lucarella on 2009- 11- 06 23:40 (updated on 2009- 11- 06 23:40)
tagged en, eric giler, ted, witricity - with 0 comment(s)

The concept of transfering energy without wires is pretty old. You can even have it now, with RFID for example (I even have a mouse that uses no battery, the pad transfer energy to the mouse using RFID; very good mouse BTW).

But Eric Giler presents a nice new concept in wireless electricity (the marketing name is Witricity), because other kind of wireless energy transfer I saw has very little power (to avoid frying your brain ;). This one works using a magnetic field instead of radio waves, which makes possible to transfer bigger amounts of energy without harm.

In the video you can see how it powers a big LCD screen for example. I don't know how efficient this will be. At first sight it looks like it would waste a lot of energy, because the magnetic field generation will be using energy all the time, even when there are no devices using it.

Here is the video:

Patch to make D's GC partially precise

by Leandro Lucarella on 2009- 11- 06 14:43 (updated on 2009- 11- 06 23:09)
tagged d, en, gc, precise - with 0 comment(s)

David Simcha has announced a couple of weeks ago that he wanted to work on making the D's GC partially precise (only the heap). I was planning to do it myself eventually because it looked like something doable with not much work that could yield a big performance gain, and particularly useful to avoid memory leaks due to false pointers (which can keep huge blocks of data artificially alive). But I didn't had the time and I had other priorities.

Anyway, after some discussion, he finally announced he got the patch, which he added as a bug report. The patch is being analyzed for inclusion, but the main problem now is that it is not integrated with the new operator, so if you want to get precise heap scanning, you have to use a custom function to allocate (that creates a map of the type to allocate at compile-time to pass the information about the location of the pointers to the GC).

I'm glad David could work on this and I hope this can be included in D2, since is a long awaited feature of the GC.

Update

David Schima has been just added to the list of Phobos developers. Maybe he can integrate his work on associative arrays too.