REP files may be specified in all load calls with the LOAD- or START-EXECUTABLE-PROGRAM (or LOAD- and START-PROGRAM) commands and with the ASHARE and BIND macros.
A REP file is always associated with a load unit. The REP records contained in it can be used for bytewise corrections to the individual modules of a load unit by the same method as when loading the BS2000 Control System (see the “Introductory Guide to Systems Support“ [9].
The REP records may be applied to all modules in the link context or be restricted to just the modules of the load unit (REPSCOP=CONTEXT or UNIT). Masked symbols may also be included for REP processing in the link context.
When the load operation has been completed, DBL opens the REP file associated with the load unit, reads in the REP records, and then applies them to the modules of the load unit or to all modules in the link context, taking the NOREF file, if any, into account. A NOREF file contains a list of symbols (CSECTs and ENTRYs) that are not relevant for REP processing (see "NOREF files").
Corrections that affect code in a system context are controlled by the BLS Lock Manager. The system context involved is protected against any other write access during the entire link/load process (including REP processing).
Format of REP records and REP files
REP records must be supplied in the same format that is used for REPs of the BS2000 Control System. This also applies to relocatable REPs. A detailed description of the format of REP records and REP files can be found in the “Introductory Guide to Systems Support” [9].
Every REP record is checked for the correct format before it is processed. This includes, among other things, the data contained in it, the parity byte, the module version, and the module name. The class identifier (column 70) has no significance for load units and is therefore not taken into account.
Any invalid or unrecognized REP records are logged on SYSOUT, and processing continues with the next REP record.
If the REP file specified in the load call does not exist, REP processing is aborted with error message BLS0977/BLP0977, and the load unit is loaded without REP corrections. In the case of other DMS errors on accessing the REP file, DBL displays message BLS0998/ BLP0998 and offers a second access attempt. If this attempt also fails, the load unit is loaded without REP corrections.
REP files for subsystems
A REP file that is associated with a subsystem must comply with the following naming convention:
SYSREP.<subsystem-name>.<subsystem-version>
The REP file should be shareable, especially if the subsystem has not been preloaded, but is loaded instead at the first call.
Return information and error flags
The following BLS messages are output when processing REP files:
BLS0990/BLP0990 | on successfully opening the REP file |
BLS0980/BLP0980 | for each comment in the REP file |
BLS0989/BLP0989, | if errors occur during REP processing |
NOREF files
A NOREF file is associated with a REP file and contains a list of CSECTs and ENTRYs that need not be taken into account during REP processing. In other words, if DBL cannot find a CSECT or an ENTRY for which there is a REP record, DBL will search for it in the NOREF file. If the symbol in question is listed in the NOREF file, DBL will skip that REP record without an error message.
This enables a REP file to be applied to:
software products consisting of multiple subsystems or load units
subsystems or programs consisting of multiple load units.
Format of NOREF files
A NOREF file is a SAM file of variable length. It consists of 8-byte records (one record per symbol name), which are delimited by blanks. The first record of the NOREF file contains the number of subsequent records in the first four bytes in hexadecimal notation.
Naming convention for NOREF files
DBL can process any NOREF file that complies with the naming conventions for BS2000 REP files:
If the REP file name specified in the load call includes the name component “SYSREP”, DBL replaces that name component with “SYSNRF” and searches for a NOREF file under that name.
Otherwise, DBL searches for a NOREF file with the same name as the main library, but with the additional suffix “.NOREF”.
DBL does not issue any message if no NOREF file is found.
On opening the NOREF file successfully, DBL displays message BLS0995/BLP0995. Message BLS0996/BLP0996 or BLS0997/BLP0997 is output if an error occurs during NOREF processing.