I do not know what a "NOP" is in Metasploit Framework or otherwise.
What I do know
MS Unleashed says, "Nops keep the payload sizes consistent." A few question posts mention buffer overflows.
What I would like to know
Why do Nops keep payload sizes consistent? What do Nops keep payload sizes consistent with? What is a Nop, exactly? An acronym? A pseudonym? Does it stand for something longer?
Is a "nop" a process or data? (EG: do you "run" a nop, or do you "send" a nop?) Why do they call them "sleds" and "sledges"? (I am inferring both of these names refer to the thing you slide down hills with in the winter time, which seems to imply that a "nop" somehow lubricates some sort of data transaction)
Where I've already looked for answers