Execute Channel Program (EXCP) Section

This section contains the I/O information for a specific DD Name/Device address pair for the address space. There can be multiple EXCP sections for a given address space.

With the SMFPRMxx parameter EMPTYEXCPSEC(NOSUPPRESS) specified, the system generates one EXCP section for each SMS candidate volume. The SMS candidate volume EXCP section contains only the DD name, SMF30DDN. All other fields in the EXCP section are zeros. This is the default behavior. Also by default, SMF generates a similarly empty EXCP section for non-dataset allocations like DD DUMMY or spool file allocations.

With SMFPRMxx parameter EMPTYEXCPSEC(SUPPRESS) specified, no empty EXCP sections are created for non-allocated candidate volume in the SMS storage group, or for empty EXCP sections that are generated for non-dataset allocations like DD DUMMY or spool file allocations.

Triplet Information

This section is located on the record using the following triplet fields, which are located in the ‘header/self-defining’ section:

Offset: SMF30EOF
Length: SMF30ELN
Number: SMF30EON - Reports the number of EXCP sections on the current record.

This section also has additional control fields in the ‘header/self-defining’ section:

SMF30EOS reports the number of EXCP sections for the current period on Subsequent Type 30 records. These are known as the ‘chained’ Type 30 records.
SMF30EOR also reports this same information but is only a 2 byte field which can overflow so SMF30EOS is the preferred field for processing this data.

Offsets		Name	Length	Format	Description
0	0	SMF30EXP	30	structure	Data set access information. Note: Virtual I/O devices are identified by the following: Device Class 0 Unit Type 0 Device Number X'7FFF' It is important to understand the following: Allocation messages for VIO data sets will show VIO ALLOCATED TO ddname. SMF records will show VIO unit addresses as X'7FFF'. The actual in-storage UCB built for VIO will show address X'3FFF'. For example, the followin messages indicate that ddname is not allocated to a Virtual I/O device, but is instead allocated to a real device whose unit address is X'3FFF' or X'7FFF' respectively. IEF237I X'3FFF' ALLOCATED TO ddname IEF237I X'7FFF' ALLOCATED TO ddname
0	0	SMF30DEV	1	binary	Device class.
1	1	SMF30UTP	1	binary	Unit type.
2	2	SMF30CUA	2	binary	Device number.
4	4	SMF30DDN	8	EBCDIC	DD Name used to access the data set.
12	C	SMF30BLK	4	binary	Count of blocks issued for the device against the data set. This field has a maximum value of X'FFFFFFFF' = 4,294,967,295. If it exceeds that value it will wrap to zero and then continue to increase again for additional blocks transferred.
16	10	SMF30BSZ	2	binary	Largest blocksize of the data set Bit Meaning when set 0 Indicated changed blocksize for the data set. Post processors should use this field to avoid the possibility of negative numbers. 1-15 Largest blocksize of the data set.
18	12	SMF30DCT	4	binary	Device connect time for this data set (in 128 micro-second units). For DIV object, device connect time is not collected by SMF; however, this field may not always be zero. For example, if a user is using a DIV data set and calls a VSAM utility to process it using the same DD statement, this will result in device connect time being charged by VSAM to the DIV object.
22	16	SMF30XBS	8	binary	Block size value.