Documentation: admin-guide: Fix typos

Finally, the [KMG] suffix is commonly described after a number of kernel

parameter values. These 'K', 'M', and 'G' letters represent the _binary_

multipliers 'Kilo', 'Mega', and 'Giga', equalling 2^10, 2^20, and 2^30

multipliers 'Kilo', 'Mega', and 'Giga', equaling 2^10, 2^20, and 2^30

bytes respectively. Such letter suffixes can also be entirely omitted:

.. include:: kernel-parameters.txt

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Reliability, Availability and Serviceability (RAS) is a concept used on

servers meant to measure their robusteness.

servers meant to measure their robustness.

Reliability

  is the probability that a system will produce correct outputs.

* CPU – detect errors at instruction execution and at L1/L2/L3 caches;

* Memory – add error correction logic (ECC) to detect and correct errors;

* I/O – add CRC checksums for tranfered data;

* I/O – add CRC checksums for transferred data;

* Storage – RAID, journal file systems, checksums,

  Self-Monitoring, Analysis and Reporting Technology (SMART).

By monitoring the number of occurrences of error detections, it is possible

to identify if the probability of hardware errors is increasing, and, on such

case, do a preventive maintainance to replace a degrated component while

case, do a preventive maintenance to replace a degraded component while

those errors are correctable.

Types of errors

On the above example, a DDR4 SO-DIMM memory module is located at the

system's memory labeled as "BANK 0", as given by the *bank locator* field.

Please notice that, on such system, the *total width* is equal to the

*data witdh*. It means that such memory module doesn't have error

*data width*. It means that such memory module doesn't have error

detection/correction mechanisms.

Unfortunately, not all systems use the same field to specify the memory

There, the DDR3 RDIMM memory module is located at the system's memory labeled

as "DIMM_A1", as given by the *locator* field. Please notice that this

memory module has 64 bits of *data witdh* and 72 bits of *total width*. So,

memory module has 64 bits of *data width* and 72 bits of *total width*. So,

it has 8 extra bits to be used by error detection and correction mechanisms.

Such kind of memory is called Error-correcting code memory (ECC memory).

.. [#f1] Please notice that several memory controllers allow operation on a

  mode called "Lock-Step", where it groups two memory modules together,

  doing 128-bit reads/writes. That gives 16 bits for error correction, with

  significatively improves the error correction mechanism, at the expense

  significantly improves the error correction mechanism, at the expense

  that, when an error happens, there's no way to know what memory module is

  to blame. So, it has to blame both memory modules.