How to Interprete the Counters Kept at "/usr/include/sys/dk.h"

[Yuhan Yao]

I am having trouble interpreting the counters which are defined in 
/usr/include/sys/dk.h, as excerpted below.  There are no comments 
as if they were supposed to be obvious, well, not to me.  I really
hope that the knowledgable netters here can enlighten me on this
matter.  

It seems to me that all these counters are accumulative, except
for dk_busy, which may be used to indicate whether any disk is busy.
"dk_time" seems to account for the duration (in 1/100 second) when the
disk is busy;  "dk_seek" is for the number of seeks, dk_xfer for number
of disk block transfers; "dk_read" for number of reads; but then what 
about "dk_wds" and "dk_bps'?  I can't figoure out what the acronyms
stand for in the first place!
Please notice that the other fields that seemed to have meaning to me
aren't really that apparent, the above description is only my guess work.

I'd really appreciate any input regarding these counters.
Thanks in advance.


P.S.  /* excerpts from /usr/include/sys/dk.h" */


/*	@(#)dk.h 2.6 88/02/08 SMI; from UCB 4.2 81/02/19	*/

/*
 * Instrumentation
 */
#define	DK_NDRIVE	4

#ifdef KERNEL
int	dk_busy;
long	dk_time[DK_NDRIVE];
long	dk_seek[DK_NDRIVE];
long	dk_xfer[DK_NDRIVE];
long	dk_wds[DK_NDRIVE];
long	dk_bps[DK_NDRIVE];
long	dk_read[DK_NDRIVE];

long	tk_nin;
long	tk_nout;
#endif