Volume header section - VTOC index component I/O statistics

I/O response and service time components are recorded in multiples of 128 micro-seconds.

Offsets		Name	Length	Format	Description
0	0	S42VXIOR	4	binary	Response time.
4	4	S42VXIOC	4	binary	Average I/O connect time.
8	8	S42VXIOP	4	binary	Average I/O pending time.
12	C	S42VXIOD	4	binary	Average I/O disconnect time.
16	10	S42VXIOQ	4	binary	Average control unit queue time.
20	14	S42VXION	4	binary	Total number of I/Os.
3990 Control Unit Cache Statistics:
24	18	S42VXCND	4	binary	Number of cache candidates.
28	1C	S42VXHIT	4	binary	Number of cache hits.
32	20	S42VXWCN	4	binary	Number of write candidates.
36	24	S42VXWHI	4	binary	Number of write hits.
40	28	S42VXSEQ	4	binary	Number of sequential I/O operations.
44	2C	S42VXRLC	4	binary	Number of record level cache I/O operations.
48	30	S42VXICL	4	binary	Number of inhibit cache load I/O operations.
52	34	S42VXDA0	4	binary	Average I/O device-active-only time.
56	38	S42VXRDD	4	binary	Average disconnect time for reads.
60	3C	S42VXRDT	4	binary	Total number of read operations.
64	40	S42VXHRD	4	binary	Number of zHPF read operations (one microsecond).
68	44	S42VXHWR	4	binary	Number of zHPF write operations (one microsecond).
72	48	S42VXR1U	4	binary	Response time (one microsecond).
76	4C	S42VXC1U	4	binary	Average I/O connect time (one microsecond).
80	50	S42VXP1U	4	binary	Average I/O pending time (one microsecond).
84	54	S42VXD1U	4	binary	Average I/O disconnect time (one microsecond).
88	58	S42VXQ1U	4	binary	Average control unit queue time (one microsecond).
92	5C	S42VXA1U	4	binary	Average I/O device-active-only time (one microsecond).
96	60	S42VXT1U	4	binary	Average disconnect time for reads (one microsecond).
100	64	S42VXB1U	4	binary	Average device busy time (one microsecond).
104	68	S42VXM1U	4	binary	Average initial command response time (one microsecond).
108	6C	*	4	–	Reserved.