BK1 is the first part of the processor pair BK1/BK2. BK1 permits the user to breakpoint the print file without delving into the mysteries of catalogued files, @BRKPT, and @SYM. BK1 is called to establish breakpoint mode; any output following the BK1 call will be diverted. Format:
@BK1[,options] filenm., equip/maxgran,reel-or-packid,retention
All parameters are optional. Filenm specifies the file name to which the output is to be sent. If the file is already assigned to the run, the breakpoint is simply performed. If the named file is not assigned to the run, it is dynamically assigned, using the options, equipment type, max granules, reel number (or removable packid), and retention specified on the BK1 card. Of course, the granule and packid fields are meaningful only if the file is mass storage; and the reel and retention fields are meaningful only for tape. The only departures from system standards are that the field after the equipment type is a max granules rather than initial reserve field; and that if all options are omitted, the options CPR will be assumed.
If only the filename portion of file is used (i.e., no qualifier or keys), it does not have to be followed by a period.
If all filename specifications are omitted from the BK1 statement, a unique file name will be created using the default options CPR; and output will be sent to that file. Thus in the case of a demand user wishing to create batch output, the statement used is simply: @BK1
The following options or option combinations have special meaning to BK1 and will not be used on the @ASG of the breakpoint file:
CU - The breakpoint file will actually be catalogued by BK1 rather than just assigned with the C or U option; it will be @ASG,CY; @FREE,R; and @ASG,A. The CU combination will be ignored if no filename is specified, or if either the R or W option is present.
This option combination is useful for a long breakpointed run which errors off or has the system crash on it. Most of the run's print output will still be catalogued and available for inspection.
D - The breakpoint file will be deleted, if it exists, before being assigned; an @ASG,AY and @FREE,DR will be performed on it first.
Thus, a '@BK1,DCU filename.' will be the equivalent of a '@DELETE,C', '@CAT', '@ASG,A', and '@BRKPT' of the file.
HELP - Print a Help Page summarizing BK1 calls and options.
Y - Submit a '@SYM,D PRINT$' via CSF$ before breakpointing to the file. In a batch run, this will have the effect of deleting the current print file before breakpointing to the new one.
Z - Submit a '@SYM,DF PRINT$' before breakpointing. This is the same as the Y option except that the added F option on the @SYM will prevent a trailer page in case the job should error off before reaching the BK2.