Parameter Description for BUFDEF

BELOWBUF=
Specifies the maximum number of buffers that JES2 allocates below 16 megabytes in virtual storage and a usage warning level for those buffers. JES2 uses these buffers to store data records read in from spool.
LIMIT=nnnn
Specifies the maximum number of buffers (10-2000) JES2 allocates below 16 megabytes in virtual storage.

If the BELOWBUF parameter is not specified, the following formula is used to calculate initial value for BELOWBUF:

  BELOWBUF=LIMIT=
  20
  + 1 * (number of RDRnn statements)
  + N2 * (number PRTnn statements - N1)
  + N1 * N2 * (nnn from TRKCELL=nnn on SPOOLDEF)
  + N3 * (number PUNnn statements)
  + (1 + N4 + N5) * (number of LINEnnn statements)

  WHERE
  N1 = Number of printers specifying TRKCELL=YES
  N2 = 2 if DBLBUFR=YES on PRINTDEF, else 1
  N3 = 2 if DBLBUFR=YES on PUNCHDEF, else 1
  N4 = 2 if RDBLBUFR=YES on PRINTDEF, else 1
  N5 = 2 if RDBLBUFR=YES on PUNCHDEF, else 1
Note: Most of the input values to this formula are for active devices at peak load periods on a single member of your multi-access spool complex.
Note: Use this parameter to increase the limit for the JNUM resource that is reported on the HASP050 message.

Performance Considerations: Because all JES2 buffers are maintained in a dynamic pool until required by an active function, the appropriate number of buffers should be based on the predicted coincident occurrence of the various functions at your installation. This can vary considerably from the value determined by the formula above. If you have calculated a reasonable value for LIMIT= based on past system usage, you can continue to use that value.

If, however, you have no such past data upon which to base this value, the following guidelines and formula above provides a basis upon which to initially set this value.
  • JES2 normally requires at least 100 spool buffers. Even if your estimate of required buffers is less than 100, it should prove to be a good initial value unless your use of virtual storage is constrained.
  • Normally 450 spool buffers are required for normal JES2 operations for installations with up to 150 remote workstations that are active during peak load periods.

Modification: $T BUFDEF operator command to increase the limit. Hot start to decrease the limit.

WARN=nnn|80
Specifies a threshold percentage (0-100) of the maximum buffer use at which JES2 issues the $HASP050 message to warn the operator of a resource shortage. If you do not want JES2 to issue a message, specify zero for this parameter.

Modification: $T BUFDEF operator command.

EXTBUF=
Specifies information about the control block buffers. JES2 allocates these buffers above 16 megabytes in virtual storage; JES2 control blocks read in from spool reside here.
LIMIT=nnnn
Specifies the maximum number of buffers (10-9999) JES2 allocates above 16 megabytes in virtual storage. The "Performance Considerations" listed under BELOWBUF=LIMIT=nnnn also apply for this parameter.

If the EXTBUF parameter is not specified, the following formula is used to calculate initial value for EXTBUF:

  EXTBUF=LIMIT=
  20
  + 4 * (number of RDRnn statements)
  + N2 * (number PRTnn statements - N1)
  + N1 * N2 * (nnn from TRKCELL=nnn on SPOOLDEF)
  + N3 * (number PUNnn statements)
  + (4 + N4 + N5) * (number of LINEnnn statements)
Start of change  + 2 * (number of JQRP PCEs)
  + 1 * (number of CNVT PCEs)
  + 3 * (number of OUTPUT PCEs)
  + 4 * (number of PURGE PCEs)End of change
  + 2 * MIN(50,nnn/1024 from JOBNUM=nnn on JOBDEF)
  
  WHERE
  N1 = Number of printers specifying TRKCELL=YES
  N2 = 2 if DBLBUFR=YES on PRINTDEF, else 1
  N3 = 2 if DBLBUFR=YES on PUNCHDEF, else 1
  N4 = 2 if RDBLBUFR=YES on PRINTDEF, else 1
  N5 = 2 if RDBLBUFR=YES on PUNCHDEF, else 1)

Start of changeThe number of JQRP PCEs has no external and is set to 10
The number of CNVT, OUTPUT, and PURGE PCEs is set on the PCEDEF initialization statementEnd of change
Note: Most of the input values to this formula are for active devices at peak load periods on a single member of your multi-access spool complex.

Modification: $T BUFDEF operator command to increase the limit. Hot start to decrease the limit.

WARN=nnn|80
Specifies a threshold percentage (0-100) of the maximum buffer use at which JES2 issues the $HASP050 message to warn the operator of a resource shortage. If you do not want JES2 to issue a message, specify zero for this parameter.