LOGR SUBSYS dynamic allocation considerations

Dynamic allocation (SVC99) can also be used to allocate a LOGR SUBSYS DD for accessing log stream data.

Refer to the information in z/OS MVS Programming: Authorized Assembler Services Guide dealingwith the SVC 99 Parameter List for details on using dynamic allocation.

IBM® recommends using, at minimum, the following text unit keys

DALDDNAM   DDNAME
DALDSNAM   DSNAME - log stream name
DALSTATS   Dataset Status - SHR
DALRECFM   RECFM
DALBLKSZ   BLKSIZE
DALSSNM    Subsystem name - LOGR
DALSSPRM   Subsystem Parameters
 — exit name, SUBSYS-options 1, SUBSYS-options2

The following examples show how to code the text units related to the LOGR SUBSYS options. The text unit key is identified followed by an example of the EBCDIC characters that would be used for the particular example. The text units would need to be coded as required by the Dynamic Allocation processing. Note that spaces between the characters is for readability purposes.

Subsystem Name Request Specification - Key = '005F'

Example: To request subsystem LOGR, code: 
 KEY   #     LEN   PARM
 005F  0001  0004  D3 D6 C7 D9

Subsystem Parameter Specification - Key = '0060'

To specify these three parameters for the LOGR subsystem IFBSEXIT,'FROM=OLDEST,TO=YOUNGEST',DEVICESTATS then code:

 Example 1:
 KEY   #     LEN   PARM
 0060  0003  0008  C9 C6 C2 E2 C5 E7 C9 E3

 LEN   PARM  
 0017  C6 D9 D6 D4 7E D6 D3 C4 C5 E2 E3
       6B E3 D6 7E E8 D6 E4 D5 C7 C5 E2 E3 
 
 LEN   PARM 
 000B  C4 C5 E5 C9 C3 C5 E2 E3 C1 E3 E2

Example 2:

Here are a few examples of how to code the SUBSYS parameters when reading CICS® log streams.

Assume the corresponding JCL DD options are desired (ignoring the JCL column alignment) and the Subsystem name text unit (key = '005F') is also coded as above.

 a
 SUBSYS=(LOGR,DFHLG520,"FROM=(1998/350,12:00:00),GMT",
      COMPAT41)
 KEY   #    LEN   PARM  
 0060  0003 0008  C4 C6 C8 D3 C7 F5 F2 F0

 LEN   PARM   
 001C  C6 D9 D6 D4 7E 4D F1 F9 F9 F8 61 F3 F5 F0 
       6B F1 F2 7A F0 F0 7A F0 F0 5D 6B C7 D4 E3

 LEN   PARM
 0008  C3 D6 D4 D7 C1 E3 F4 F1

 b.
 SUBSYS=(LOGR,DFHLGCNV,"FROM=(1998/287,00:00:00),
    TO=(1998/287,17:30:00),LOCAL',DELETE) 

 KEY   #    LEN   PARM
 0060  0003 0008  C4 C6 C8 D3 C7 C3 D5 E5

 LEN   PARM
 0035  C6 D9 D6 D4 7E 4D F1 F9 F9 F8 61 F2 F8 F7
       6B F0 F0 7A F0 F0 7A F0 F0 5D 6B E3 D6
       7E 4D F1 F9 F9 F8 61 F2 F8 F7 6B F1 F7	
       7A F3 F0 7A F0 F0 5D 6B D3 D6 C3 C1 D3

 LEN   PARM 
 0006  C4 C5 D3 C5 E3 C5

 c.
 SUBSYS=(LOGR,DFHLG520,,LASTRUN)

 KEY   #     LEN   PARM
 0060  0003  0008  C4 C6 C8 D3 C7 F5 F2 F0

 LEN   PARM  LEN   PARM
 0000  -     0007  D3 C1 E2 E3 D9 E4 D5