ktune parameter npbuf

[Rob Stampfli]

In the User's Manual for the 3B1 Unix-PC, vers 3.5, there is a command called
ktune(7), which allows one to tune certain Unix parameters in the kernel.
One of the parameters is called npbuf:

npbuf	Number of buffer headers available in the raw I/O pool of headers
	Range: 4 up to system capacity.  (Default: 16)

Can someone give me more information on this parameter.  When is one of
these used?  Are they consumed by uucico?  rn?  One per open fd (raw mode)?
I thought I knew Unix, but this one is new to me.

Tnx,
-- 
Rob Stampfli, 614-864-9377, res at kd8wk.uucp (osu-cis!kd8wk!res), kd8wk at n8jyv.oh