-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 2015-03-17 02:56, Felix Miata wrote:
4k, like 512, is also an abstraction. Even though the bytes are advertised as, and universally considered to be discrete bits, on or off with no state in between, the recording surfaces at the foundational level are analog, a discovery I made only a week or so ago.
All digital electronics are basically analog underneath. Assume a supply voltage of 5 volts. Typically it is said that a #0 is zero volts, and a #1 is 5 volts. Not true. It is rather something like "between 0 and 2 volts it is considered a zero, and above 3 volts it is considered a one". Notice that there is a gray undefined area in the middle. Basically, as speeds rise the voltages may not have time to reach a value that can clearly be interpreted as a one or a zero. Magnetic media is similar... on modern disks with so high densities the device has to "decide" if what it is seeing is a one or a zero. Sometimes it makes mistakes. Apparently, they are so probable that they need error correction methods. You see this by looking at the raw error figures out of smartctl. - -- Cheers / Saludos, Carlos E. R. (from 13.1 x86_64 "Bottle" (Minas Tirith)) -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iF4EAREIAAYFAlUIg+0ACgkQja8UbcUWM1z+dAD/fdDGGJqmU/3gAO50Cylm8xFG of4jysUINk/W/QZ+Ca8A/iFWJ8rdFU9YdfKq5t28kXdGs1pQUzmlz0THP/+1czSa =ECIS -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org