Mostly off topic nitpicking, but...

In the International System of Units (SI):

  k: kilo-   = *1000, prefix
  K: kelvin  = the unit of thermodynamic temperature

In the IEEE 1541-2002 standard:

  b: bit     = the basic unit of information
  B: byte    = a set of adjacent bits (usually, but not necessarily, eight)

This thread contains all possible combinations of the above, with unclear intent, and I don't like it at all. It's not that hard to be unambiguous.

https://en.wikipedia.org/wiki/International_System_of_Units

https://en.wikipedia.org/wiki/IEEE_1541-2002