On Aug 10, 2017, at 10:46 AM, mad.scientist.at.large@tutanota.com wrote:
is that because the drive is compressing the information?
No. I believe by “probabilistic representation” the parent poster simply means that in any given data cell, you don’t have a hard “1” or “0”, you have some voltage potential which can be interpreted as some number of 1 or 0 bits, often 3 bits or more.
Between that fact and wear-leveling, you can’t take a simple voltage measurement on a data cell and say, “This cell contains 011.” You need more smarts about what’s going on to turn the voltage reading into the correct value.
As the drive’s data cells wear out, the drive’s ability to do that correctly and reliably degrade. Thus cell death, thus drive death, thus filesystem death, thus backups, else sadness.
And please don’t top-post.
A: Yes.
Q: Are you sure?
A: Because it makes the flow of conversation more difficult to read.
Q: Why shouldn’t I top-post?