Pathway/XM System Management Manual

PXMCFG Statements and PXMCHK Utility
Compaq NonStop™ Pathway/XM System Management Manual—426761-001
10-65
SET TCP
OFF
directs a TCP configured from this TCP template to check its memory for a
version of the called program unit. If the program is already in the TCP code
area and the TCP checked the directory file after the latest REFRESH-CODE
command, the TCP uses that version of the program and does not read the
directory file.
If the called program unit is not in memory, the TCP checks the directory file for
the latest accessible version of the called program.
This is the recommended setting for a production environment. Pathway
application performance is better when the TCP does not have to check the
directory file every time a SCREEN COBOL program unit is called. Also,
setting the CHECK–DIRECTORY attribute to OFF and using the REFRESH–
CODE TCP command when a new version of a SCREEN COBOL program is
put into production enables better tracking of SCREEN COBOL programs.
For more information about this option, see the REFRESH-CODE TCP
command.
CODEAREALEN double-number
specifies the number of bytes a TCP allocates in its extended data segment for
SCREEN COBOL object code.
double-number can be a value from 0 through 2147483647. If you omit this
value, the default is 65536 bytes.
The value you assign for this attribute depends on the number and the size of the
screen programs in your applications and also on the available swap space. Some
guidelines for estimating this attribute are:
•
Use the size of the SCREEN COBOL programs (the screen data plus the
RUNUNIT SIZE listed for these programs compiled with MAP) that make up
the applications for this TCP. Note that not all of the screen programs are
executed all of the time, and that the most regularly used programs determine
the amount of code space most often required.
•
Making the code area slightly larger than necessary can prevent the TCP from
having to perform unnecessary code fetching during TCP operation. The larger
code area only costs you disk space for the swap file.
•
After running the TCP with STATS ON, check the STATS TCP display
information and adjust the size of the code area to the actual value required.
Note. This option does not ensure that the TCP uses the latest accessible version of
the called program unit.
Note. The maximum value allowed for this parameter exceeds current system limitations,
and the default value might be too small for some production environments. The code area
length is limited by other aspects of your system, so that the practical maximum value is
not a fixed number. Therefore, it is recommended that you estimate an appropriate value
for the code area length according to the needs of your application.