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The Many Paths To Data Corruption
Runnin'Scared writes "Linux guru Alan Cox has a writeup on KernelTrap in which he talks about all the possible ways for data to get corrupted when being written to or read from a hard disk drive. This includes much of the information applicable to all operating systems. He prefaces his comments noting that the details are entirely device specific, then dives right into a fascinating and somewhat disturbing path tracing data from the drive, through the cable, into the bus, main memory and CPU cache. He also discusses the transfer of data via TCP and cautions, 'unfortunately lots of high performance people use checksum offload which removes much of the end to end protection and leads to problems with iffy cards and the like. This is well studied and known to be very problematic but in the market speed sells not correctness.'"
The most common way for young data to be corrupted is to be saved on a block that once contained pornographic data. As we all know, deleting data alone is not sufficient, as that will only remove the pointer to the data while leaving the block containing it undisturbed. This allows a young piece of data to easily see the old porn data as it is being written to that block. For this reason, it is imperative that you keep all pornographic data on separate physical drives.
In addition, you should never access young data and pornographic data in the same session, as the young impressionable data may get corrupted by the pornographic data if they exist in RAM at the same time.
Data corruption is a serious problem in computing today, and it is imperative that we take steps to stop our young innocent data from being corrupted.
There must be 50 ways to lose your data.
Oh, say does that Star-Spangled Banner entwine / The myrtle of Venus with Bacchus's vine?
I was expecting an article on using MySQL in production.
Or errors can corrupt both the data and the checksum so they match each other.
This is about as likely as simultaneously winning every current national and regional lottery on the planet. And then doing it again next week.
And if we're talking about a 512 bit hash then it's possible that a new planet full of lotteries will spontaneously emerge from the quantum vacuum. And you'll win all those too.