Roxanne Khamsi reports for New Scientist of Africa’s soil health crisis:
Population pressures combined with limited access to fertilisers threaten the future of farming in Africa, a new study warns. The report highlights the continent’s
soil health crisis, revealing that three-quarters of its farmlands are severely degraded.
Worldmapper is a collection of world maps, where territories are re-sized on each map according to the subject of interest.
Shown above is the map of total elderly. Check out the size of USA to, say, sub-Saharan Africa. Illuminating.
Tip of the hat to Stephen J. Dubner of the Freakonomics blog.
Malcolm MacDonald submitted some Free Hands drywall cleats to Cool Tools:
After renting a 100 lb drywall lift for a weekend for $60 to get the largest ceiling panels positioned, I found Free Hands on the internet. They are simple plastic cleats which you screw into the studs or joists to provide a ledge to support an edge of the drywall while you position and screw it in place.
Being at about the same point in our basement renovation, I think I might just have to pick up some of these.
I’m about halfway through reading William Gibson’s Pattern Recognition and I’m having a tough time getting into it. The story so far seems terribly contrived: a woman tries to track down the anonymous creator of a series of video segments that appear from nowhere on the internet. What makes it even more difficult is Gibson’s writing style. It seems as though he’s trying too hard to impress his readers with his writing ability, rather than just telling the story. I really hope it gets better, but I’m not expecting much.
Anyways, that the book is a dud doesn’t annoy me as much as it might if I’d paid the regular price for it at Amazon or Chapters. As it is, I purchased it at the Riverworks Book Market in St. Jacobs for $5.
Almost all their books are $5. It’s great!
They aren’t always the latest books. And they haven’t got as large a selection as the big chains. But for $5 a book — and those are new books — I can afford to pick up a few duds.
Riverworks has quickly become one of my favourite local shops. If you are in the area, I definitely recommend it.
Michael Hiemstra tipped me off about the latest in the distinguished Lecture Series at the University of Waterloo: a talk by Andrew Tanenbaum on MINIX 3. Michael was unfortunately not able to make it, so I thought I’d write him a brief summary.
He didn’t veer much from what you can find on MINIX 3 website.
He began by saying that the current crop of popular operating systems (Windows, Linux, FreeBSD, etc) is miserably unreliable. And it’s no wonder. Their kernels contain millions of lines of source code, which, if we are to believe most studies, contain bugs at a rate of about 6-16 per thousand lines of code. What’s more, the buggiest part of these operating systems, the hardware drivers, operate at the kernel level, leading any bug in any driver to crash the entire system. He likened this design to an aircraft carrier where every time a toilet backs up, it launches some missiles.
MINIX aims to be a reliable operating system. It accomplishes this by having a very small kernel (~4000 lines of code) whose primary responsibility is interprocess communication. Drivers run as user processes so that when they crash, they don’t bring down the entire system. In fact, another service (called the reincarnation service) monitors all the drivers and restarts any that have crashed or no longer respond to pings.
It is a layered operating system. Applications utilize services that utilize drivers that utilize the kernel. Communication between the various layers is conducted via fixed-length messages. Because the messages are fixed length and because data and instructions are kept separate in the runtime image, the potential for buffer overflow vulnerabilities is greatly reduced.
He put up some performance benchmarks that show that by running the drivers in user space, the system is slightly slower than the traditional monolithic kernel approach, but not enough to keep any reasonable person from using it (~12% on average), especially given the higher reliability.
It was an entertaining talk, and well worth the trip. They even handed out bootable CDs with MINIX on it. It’s a shame Michael couldn’t make it. I think he would have enjoyed it.
Last week’s news… Ontario first to subsidize solar electric power:
Ontario has become Canada’s first province to offer cash incentives for homeowners or businesses that install solar electric power generators.
I returned from my trip to Santa Clara on Friday night.
If you are at all curious, our long talk at EclipseCon went fairly well. It was scheduled in the second last slot of the last day of the convention, at which point nobody is especially energetic, so it was hard to tell from the smattering of applause at the end whether anybody actually got anything out of it. In any event, they weren’t energetic enough to throw any rotten produce, so I assume it went well.
We even made the photos page (here and here). That’s me on the right.