Friday, January 29, 2010

My beef with Linux RAID

I have used software RAID in Linux in the past, via mdadm. I believe it has resulted in lost data more times than it has saved me from losing data. I have since switched to ZFS (on FreeBSD) and have survived many situations that could have resulted in lost data.

I'd like to be able to switch back to using Linux, so I have been doing some research on Linux RAID. Today I came across this article, which contains the following text:

For a RAID-1 config with two disks...If both blocks were readable (i.e. were read from the disk, without the disk indicating any sort of error condition), but there was a mis-compare, then the data from the highest-numbered disk is copied to the other disk. This results in a 50-50 chance that good data was over-written by bad. Furthermore, this is done silently: no syslog messages indicate either a mis-compare, or that a repair action was taken.
That's right! mdadm doesn't checksum your data to prevent this from happening! ZFS does. So, for example, you could write random data to one of your drives:

cat /dev/random > /dev/hda1

In ZFS, no problem! In RAID-1.... fail?

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Baby Food

This is the time when Ada begins trying food. She has shown the signs that she is ready: sitting up, grabbing everything and putting it in her mouth, gagging; these skills develop simultaneously in babies. Also, she just turned 6 months old, which is a common time for breastfed babies to start trying food.

This period is all about tasting. She eats very little. She plays with her food. This is baby-led weaning.

Ada has tried apples, grapefruit, lemon, carrot, squash, celery, tomato, and avocado. She is eager to taste anything. She puckered up when she tried lemon, but kept going back for more.

When appropriate, we give her whole chunks of food. Otherwise, as in the case of squash, we cook the food. We place the food in front of her and let her grab it and put it in her mouth. If she wants to grab the food but has trouble, we will either place it on a spoon and hand the spoon to her (when the food is mushy) or hold the food in front of her and let her guide our hands to her mouth (when the food is slippery or hard to handle).

Her two bottom teeth enable her to scrape off bits of the hard food (apples, celery, etc.). She works the food around in her mouth a bit, tasting it. Usually the food makes it way out her mouth again (that's a reflex that babies have). She swallows some food, somewhat by accident, and that passes through her without being digested.

Friday, January 22, 2010

YouTube Offers Experimental Opt-In HTML5 Video

Click here to opt-in to the HTML5 beta on YouTube. I tried it out and found that with HTML5 enabled, my CPU utilization is 1/3rd.

YouTube Offers Experimental Opt-In HTML5 Video: "bonch writes 'YouTube is now offering the experimental option to view all YouTube videos using HTML5 in H.264 format. Supported browsers are Chrome, Safari, and the ChromeFrame plug-in for Internet Explorer. Captions, ads, and annotations aren't yet supported but are coming soon.'

Read more of this story at Slashdot.


Wednesday, January 13, 2010

Organ Damage In Rats From Monsanto GMO Corn

Aaaand I told you so (or, rather, Erinne did).

Organ Damage In Rats From Monsanto GMO Corn: "jenningsthecat writes 'A study published in December 2009 in the International Journal of Biological Sciences found that three varieties of Monsanto genetically-modified corn caused damage to the liver, kidneys, and other organs of rats. One of the corn varieties was designed to tolerate broad-spectrum herbicides, (so-called 'Roundup-ready' corn), while the other two contain bacteria-derived proteins that have insecticide properties. The study made use of Monsanto's own raw data. Quoting from the study's 'Conclusions' section: 'Our analysis highlights that the kidneys and liver as particularly important on which to focus such research as there was a clear negative impact on the function of these organs in rats consuming GM maize varieties for just 90 days.' Given the very high prevalence of corn in processed foods, this could be a real ticking time bomb. And with food manufacturers not being required by law to declare GMO content, I think I'll do my best to avoid corn altogether. Pass the puffed rice and pour me a glass of fizzy water!'

Read more of this story at Slashdot.


Saturday, January 09, 2010

Golden Ratio Discovered In a Quantum World

My dad and I like the Golden Ratio. Here's something neat.

Golden Ratio Discovered In a Quantum World: "FiReaNGeL writes 'Scientists have for the first time observed a nanoscale symmetry hidden in solid state matter. 'In order to study these nanoscale quantum effects, the researchers have focused on the magnetic material cobalt niobate. It consists of linked magnetic atoms, which form chains just like a very thin bar magnet, but only one atom wide.' By artificially introducing more quantum uncertainty, the researchers observed that the chain acts like a nanoscale guitar string. The first two notes show a perfect relationship with each other. Their frequencies (pitch) are in the ratio of 1.618, which is the golden ratio famous from art and architecture. The observed resonant states in cobalt niobate are a dramatic laboratory illustration of the way in which mathematical theories developed for particle physics may find application in nanoscale science and ultimately in future technology.'

Read more of this story at Slashdot.