Month: November 2012

You’re Not Dead Until You’re Dead

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Sometimes people have near-death experiences where they “die” for a while before being resuscitation. They are in some sort of accident or incident and are pronounced clinically dead, but come back after a few minutes.

Some of these people report seeing white lights, tunnels, gardens, dead loved ones, etc. while others report nothing. The ones who see something often end up becoming more spiritual and hopeful after their experience while the ones who saw nothing often end up becoming depressed and pessimistic, even if they had previously been spiritual.

The problem is that the people who see nothing decide that because they saw nothing when they “died”, it means that there is no after-life or Heaven or reunion with lost loved ones. This is absolutely specious reasoning.

These people are missing the point that they did not die. Why in the world would they be greeted with the post-life welcome basket if they are not dying and going to be resuscitated? Does it not occur to them that God would be smart enough to know if they are actually staying dead or not or do they think that they were supposed to die, but the doctors defeated fate/God and snatched them back?

Of course this raises the question of why some people do see things when they have a near-death experience. This is likely caused by differences in the nature of the near-death experience. Some people who are pronounced clinically dead have no brain activity while others do. The people who see things are probably not actually seeing post-life imagery, but rather hallucinations caused by a mix of their spiritual beliefs and their brain suffering anoxia.

The fact is that near-death experiences prove nothing about the existence or lack thereof of an after-life. Whether or not there is an after-life (at this point) is only knowable for sure by those who actually die, and stay dead, not by anyone who comes back, which of course, means that the living continue to have no definitive way of knowing either way.

Bigger Hard-drive = More Fragile

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In one of his podcasts, Steve Gibson of GRC discussed how his program SpinRite works to attempt to recover data from defective hard-drives. He mentioned that modern drives are more susceptible to failures now due to higher data density and smaller bit sizes. This is correct, but some people don’t know what that means, so as always, an analogy is helpful.

Hard-drives store data as magnetic binary bits. As a simplification, lets say that when the drive head writes a 0, it aligns the magnetic bit to positive and to write a 1, it aligns it to negative. However, the magnetic bit isn’t a single atom. Like everything else, it is made up of lots and lots of atoms. Just like how a fridge magnet is made up of millions of tiny atoms, drive bits are made up of lots of atoms that align together to give it a specific magnetic polarity that the drive head can read and interpret as a 0 or a 1.

Now for simplicity, imagine we have an old hard-drive in which each bit on the drive platters is made up of 100 atoms. When you write data to it, the write head tries to align the 100 atoms in the bit to the same polarity (positive or negative). However, this will not always work correctly and some of the atoms may not get aligned correctly (or at all). That is, the bits are either positive or negative which correspond to either a 0 or a 1 (this is a simplification.

In our old, 100–atom/bit drive, if eight atoms are corrupt and incorrectly written, then 8% is bad and 92% is good, so when the head reads the magnetic polarity, it gets a nice, solid, clear reading.

Some time goes by and data sizes go up, so hard-drive manufacturers have to make the drives bigger, but they cannot increase the physical size of the drive. Packing in more bits into the same size means using smaller bits (i.e., higher data density).

Lets say we now have a fancy new drive that is 5x the size of the old one. Instead of using 100 atoms per bit, our new drive has only 20 atoms per bit. As a result, if eight atoms are incorrectly written, then instead of only 8% of the bit being corrupt, it is up to 40%. We still get more correct than incorrect at that rate, but the margin is much smaller (even worse if there are more than eight bad atoms).

Some more time goes by and we get a drive with 10x the size of the first drive (2x the previous one). Instead of 100, or even 20 atoms per bit, it is down to 10. Now when eight atoms are incorrect, it is 80% bad and only 20% good! That means the drive used to be very stable with eight bad atoms per bit, but is now completely unreadable.

The reliability of the drive went down as the data density went up because while there is more data per drive, there is less data per bit which makes it bigger, but less reliable and more prone to corruption and data loss.