the propellers go around (part 2)

… but not on camera.

This is part of the Toronto visit series.

So I inadvertently took a picture of the running propeller on my side of the plane, and it came out weird. And I mean, really weird (1):

The propeller does not look like this. It has like six blades spaced out evenly and all of them straight. So of course this is due to aliasing of the damned camera. But wait now, I just said not too long ago that this is photography, so indeed, I only took this and
(Read the article)

OEM laptop has max CPU frequency capped when on battery

I was playing with a laptop from HP the last couple of days and noticed that when off AC power (on battery), the maximum CPU frequency is only half of the specification. The machine runs Windows Vista. The CPU is an AMD ZM-80, duo core 2.1GHz. On AC power, the processor can reach 2.1GHz on heavy load, but on battery power, the maximum it will go to is 1.05GHz on each core. This is really a problem because performance (especially for single-threaded applications) is pitiful at those levels. In fact, 1080p HD WMV demo videos could not play smoothly just like on a four-year-old Pentium M 1.6GHz.
(Read the article)

cell phone # porting

I have a good guess now of how cell phone number porting is implemented. Had a number transferred from AT&T to Sprint. The phone actually came with a randomly assigned number and a matching MSID (mobile station id), but Sprint told me to re-program the phone with the desired number and a new non-matching MSID in the area code of the desired number.

The porting process was as follows:

  • Immediately, random number stops working, new Sprint-assigned MSID works as phone number!
  • Within minutes, AT&T cuts off connection and accounts access to old number, which ceases to work.
  • Hours later, MSID stops working as phone number, old number now rings new phone.

The fact that the MSID works as a phone number during porting and remains in the phone’s settings, must mean that it is in fact the true “phone number” identifier for the phone. The phone just gives out its stored “phone number” for the purpose of outgoing calls. I’m guessing every carrier has a pool of phone numbers in each area code to give out, and there is a static allocation database somewhere. During porting, Sprint assigns a new number from its own pool, which becomes the MSID. Then AT&T (who owns the old number) changes its databse to forward calls to the old number on to Sprint, instead of processing them internally. Finally, Sprint changes its database to take those incoming calls and forwards them to the assigned MSID.

When you get a new line, a number from the carrier’s pool is assigned so no forwarding is needed, and that must be why the MSID matches the phone number in that case.

Now, if I were to port again to a third carrier, what would they do? Maybe they’ll look up the number and discover they should talk to AT&T?

Here’s some real information which I haven’t read but maybe corroborates or discounts what I wrote.

cell phone hacking

Why are cell phone unlock keys and keygen algorithms still being sold?
I understand there is a great profit motive to guard the secret, since with this ruling, unlocking has become a legal profession (for at least the next three years), unlike warez cracking.
But come on, somebody must have an itch to set the information free, no?