UPDATE fn fn are update files containinq UPDATE control
statements and new source records. These files must have filenames that
are the same as the source input file. The first four characters of the
filetype must be "UPDT." The UPDATE command searches all accessed disks
to locate the update files. !fn is the updated source file, incorporatinq chanqes, additions, and deletions specified in the update files. The filetype is
always the same as the filetype of the source input file. fn contains a record of updates applied. If you do not want this
file written on disk, specify the PRINT option.
fn summarizes the updates applied to the source file,. !hg II1E (fn CNTRL) may not contain UPDATE control statements .• It may only list the filetypes of the files that contain UPDATE control
statements. This control file contains the records: TE1CT MACS CMSLIB TWO UPDTABC ONE UPDTXYZ where and are the filetypes of the update files. The UPDATE command applies these updates to the source file beginning with the last record in the control file. Thus, the updates in fn UPDTXYZ are applied before the updates in fn UPDTABC. When you create update files whose filetypes begin with 'UPDT', you
may omit these characters when you list the updates in the control file;
thus, the CNTRL file may be written: TE1CT MACS CMSLIB Twa ABC ONE lYZ The first column of the control file consists of an
update level identifier, which may be from one to five characters long.
These identifiers are used by VM/370 updating procedures, like the VMFASM EXEC, to locate and identify text decks produced by multilevel
updates. The first record in the control file must be a MACS record which
contains an update level identifier (TEXT) and, optionally, lists up to
eight macro library' filenames.
The information provided in the MACS card and the update level
identifier are not used by the UPDATE command unless the STK option is
specified. Thev are, however, required in the CNTRL file. 208 IBM VM/370 CMS Command and Macro Reference

r---------,
fn ASSEMBLE fn CNTRL fn UPDTABC fn UPDTIYZ fn AUXLIST L---------J fn FIIOl fn FIX02 update fn (ctl
r----------, I I , I I I I I L----------J
$fn ASSEMBLE fn UPDLOG fn UPDATES UPDATE fn fn CNTB1, fn fn tfn fn and in are used as described above, for "Multilevel Update," except that the CNTRL file contains: MACS CMSLIB TWO UPDTABC ONE UPDTXYZ TEXT AITXLIST !Q! in the filetype AUXLIST indicates that this is the filetype of an auxiliary control file that contains an additional list of updates. The
first three characters of the filetype of an auxiliary control file must
be the remaining character(s) (to a maximum of 5) may be anything. The filename must be the same as the source input file.
An auxiliary file may also be specified as:
xxxxx AUX in the control file. For example, the record: FIX TEST AUX identifies the auxiliary file fn AUITEST. Note that if you give an auxiliary control file the filetype AUXPTF, the UPDATE command assumes that it is a simple update file and does not
treat it as an auxiliary file. Also, if the update level identifier is PTF, the UPDATE command assumes a simple update file.
PREFERRED AUX FILE: A preferred AUI file may be specified. A preferred Aui-file-contains-the version of an update that applies to your version
of the source file. (There may be more than one version of the same
update if there is more than one version of the source file. For
example, you need one version for the source file that has a system
extension program product installed, and you need another version for
the source file that does not have a program product installed.) When you specify an auxiliary control file, you can specify more than
one filetype. The first filetype indicates a file that UPDATE uses only
on one condition: the files that the second and subsequent filetypes
indicate do not exist. If they do exist, this AUX file entry is ignored
and no updating is done. The files that the second and subsequent
filetypes indicate are preferred because, if they exist, UPDATE does not
use the file that the first filetype indicates. For example, assume
that the file 'fn ASSEMBLE' does exist. The control file MYKODS CNTRL: Section 2. CMS Commands 209