Why Should Engineers and Scientists Be Worried About Color? is abouthow straightforward use of colour in data visualizations can mislead youand hide information (and how to do better). Some of their examplesare eye-opening and alarming.

(Via Hacker News .)

(Since I took up photography I've had a muchincreased interest in how we perceive things, including colour.)

One of the interesting effects of setting a signal handler inyour Python program is, well, let me quote the signal module :

• When a signal arrives during an I/O operation, it is possiblethat the I/O operation raises an exception after the signal handlerreturns. This is dependent on the underlying Unix system's semanticsregarding interrupted system calls.

By 'an I/O operation' the manual means more than you might think; forexample, select.select() is affected by this.

The Linux kernel recently had a significant security issue or two wherethe root cause was that user programs could map memory at page zero, andthis lead to kernel level exploits. If you went through the same sort ofundergrad OS course that I did, you might be wondering how on earth auser process memory mapping issue leads to a kernel exploit; after all,as all of those little box diagrams tell us, the user program addressspace is one thing and the kernel address space is an entirely differentthing.

We've recently had another interesting case of 'accidental BitTorrent' on our network, different from the previoustimes. This time around it was through our VPN server, and just fromthat alone you can probably guess what happened.

Suppose that you are a user, sitting at home running BitTorrent in thebackground on your home machine while you do other things. You need toaccess some restricted on-campus thing; our generally supported way todo this is to fire up a VPN connection so that you are '