Type I Commands ,'DEFAuLj DEFAULT option specifies the'name·of the EXEC,' yyyYfyyy;' that'. is' to' be whe'n: this edit level is initialized. The EXEC is passed, the following parameters:
) I, : t • / "; " .. I, I ,I, ,. 11 , CLEAR
& 1 - ',& 2 -filetype ;'
& 3 -fHemode
& 4 - OLD or NEW
& 5 -UPDATE (exists for UPDATE FILES ONLY) It is in this "pre-processing" EXEC that the user has the oppor­ tunity to tailor the editing environment to his needs. The
DEFAULT option has a corresponding no-op option, NODEF, which may be used to override the ENTER default parameters as
specified in EDGAR $PROFILE. - The CLEAR option will cause the CP formatted screen to be
"cleared" with no intervention required by the user. This op­ tion is permitted only when the first edit level is being initial­ ized. If unspecified, CLEAR is assumed. The CLEAR option has
a corresponding no-op option, NOCLEAR, which may be used to
override the ENTER default parameters as specified in EDGAR $PROFILE. CTL, UPDATE and SEQ8 - these options are used when an "update" file is
to be created as a result of changes made during editing. Each
has a corresponding no-op operand, NOCTL, NOUPDATE and NOSEQ8, for use in overriding EDGAR $PROFILE defaults.
The UPDATE facility of EDGAR is intended primarily for programming appli­ cations where "update" streams are frequently generated. This facility allows
the user to request that changes made to a program source file while editing
be written to disk in the form of a CMS UPDATE file. Thus, the source file
remains unaltered and the update file may be applied to the source using the
CMS UPDATE command to re-create the source as it appeared after editing.
Furthermore, when editing of the source file is initiated using this facility; the
existing update file is automatically applied to the source during initialization.
Thus, the updated version of the source becomes available for editing and
changes made during this editing process are "merged" with the initial up­ dates. The resultant update file replaces the original update file.
To request the automatic update inclusion and generation, the UPDATE option
of the ENTER command must be specified. This option is ignored if the file
requested has been previously "entered" (using multiple editing levels).
When the ENTER command with the UPDATE option is issued, the requested
source file is initialized for editing. The source file must exist on disk and
must contain fixed-length, 80-character records; otherwise, an error message
is generated and ENTER will not be performed. When the source file is read,
all source records are checked for valid sequencing in columns 76-80. If the
'SEQ8' option was also specified in the ENTER command, columns 73-80 are
checked for valid sequencing. Once the source file has been initialized, the
update file is applied to the source. The file name of the update file must be I the same as that of the source and the file type must be "UPDATE". The
update file must exist on disk and must follow the rules required for a CMS
update file (see CMS "UPDATE" command in VM/370 CMS Command and 20

Macro Refer'ence', GC20-1818). If the update file does not conform to these
requirements, an error message will be generated and ENTER will not be .. , Once the requested editing level has been successfully initiated, editing may
proceed in the normal fashion. There are no restrictions on editing commands
used. Data placed in the sequencing columns (73-80) will be lost when the
update file is created as sequence numbers are automatically generated by
EDGAR. EDGAR will maintain a record of changes made in dynamic fashion
and indicate collection of "change" data by placing the characters 'UPD' at the
start of the file, status field (Figure 2, Line O. In addition, the fileid area will
reflect the name of the update file -not the original source.
When the UPDATE option is in effect for a given editing level and a "FILE" or "SAVEll (Type I) command is issued, the update file only is written to disk. The source file, therefore, remains unaltered. The fileid of the update file will
be determined in the standard fashion for a "FILE" or "SAVE" command.
The update stream generated by EDGAR will attempt to maximize the use of
the './ R ' update function. Thus if "inserted" records are found to be
adjacent to "altered" or "deleted" records in the file (or vice versa), a single
'./ R ' card will be generated followed by the necessary input cards. All data
cards written to the update file are sequenced by EDGAR regardless of the
current setting of the SERIAL command. "Altered" cards are given the same
sequence numbers as the source records they replace. "Inserted" cards are
sequenced with the highest increment divisible by ten which will not introduce
sequence errors in the resultant file. For example, if nine records are inserted
into a file between items XXXOOOIO and XXX00020 they will be sequenced XXXOOOll through XXXOOOI9. If more records are inserted than will fit in the
increment, the following records in the file are automatically "replaced" to
provide extra sequence numbers. To illustrate this using the above example,
ten records inserted between the items indicated above, would be sequenced
as XXXOOOIO through XXX00020 and the original item XXX00020 would be "replaced" as item XXX00021. EDGAR, also supports the multi-level update facility of CMS/370. A multi­
level update is controlled through the use of an update "CNTRL" file. The
structure of this file and the associated auxiliary files is described in some
detail in "IBM Virtual Machine Facility/370: CMS Command and Macro
Reference" (GC20-1818) under the discussion of the CMS "UPDATE" com­
mand. Users considering this facility for program development and mainte­
nance should evaluate its features based on this discussion. All features of the
'CNTRL', 'AUX', and 'PTF' files described for the "UPDATE" command are
supported by EDGAR.
The multi-level update function of EDGAR is invoked by specifying the "CTL" option followed by the filename of the desired control file on the "ENTER" command. Use of this option implies the "UPDATE" option. As with "UPDATE" and "SEQ8", the "CTL" option is ignored if the edit level being
entered already exists.
When initiating an edit level with the "CTL" option, the following steps are
performed by EDGAR:
1. The source file is located and read.
Type I Commands 21