See the VM / SP CMS Command and Macro Reference for information on how to
use file system macros with the extended file system. See the VM / SP System Logic
and Problem Determination Guide, Volume 2, to learn about the structure of the
VM/SP file system.
Programs That Reference System Information
Existing programs that reference internal CMS file system control information will
probably ·not function correctly under VM/SP.
Note: Unconverted programs that run with the SYSTEM attribute (privileged) or
do direct I/O (DIAGNOSE) can destroy data on (or the logical structure of) a
minidisk, making part or all of the data on that minidisk inaccessible.
Before running them on VM/SP examine any programs that perform functions sim­
ilar to the TAPE and DISK commands, programs that copy files, programs that
copy minidisks, and programs that are used to dump and restore files for backup.
Areas to be examined include: • The format of the File Status Table (FST) has been changed in several ways
including its length. Programs that reference FST copies returned by the
STATE command or FSST ATE/FSOPEN macros continue to function
because new format FSTs are converted to old formats in the copy returned to
the user.
Programs that reference fields in real FSTs (those in the FST hyperblocks or
AFTs) may not function properly. Programs that change fields in FSTs can
destroy the integrity of the file system.
Note that careful evaluation of both the program and CMS file system internal
processes may be necessary to determine what must be done with such pro­
grams. • The format and contents of the Active File Table (AFT) control block have
been significantly changed for extended format disks. The order of fields in
the AFT for 800-byte block disks has been changed. Programs referencing the
AFT should be carefully examined and must at least be reassembled before
running them even with 800-byte format disks.
The format of the Active Disk Table (ADT) has been significantly altered.
Many fields with new meaning have been added, and many existing fields have
been relocated. One such field is the disk volume label VOLID, which has
moved. • The format of most other VM/370 file system control information is different
from the VM/SP format file system. Programs that reference such data should
be carefully examined and altered before running them.
Programs that install auxiliary directories by changing the SST AT field in NUCON will not function properly if the S-disk is an extended format disk.
The CMS routine DMSLADAD should be used to install all auxiliary directo­
ries.
All programs that reference VM/370 CMS control block macros should be
reassembled under VM/SP. If the only control block referenced is NUCON, Introduction To eMS 307

the assembly is not necessary. The DMSSP and CMSLIB MACLIBs should be
specified as the macro libraries to be searched for CMS macro references with
the CMS GLOBAL command. The DMSSP MACLIB should precede the CMSLIB MACLIB, followed by any other MACLIBs needed for the
assembly.
Auxiliary Directories (AUXDIRTS) LISTFILE Command QUERY DISK Command
Other Command Changes
Auxiliary directories are logical extensions of file system directories that reside as a
part of certain programs. User programs containing auxiliary directories continue
to function on extended format disks provided that the module containing the auxil­
iary directory is regenerated in the manner normal for any movement of such a
module. CMS correctly converts internal formats so that auxiliary directories func­
tion properly as long as they are installed by calling the CMS routine
DMSLADAD.
The LISTFILE command is compatible with previous versions except that the col­
umns in which information is placed have been moved. Programs that use the CMS EXEC file produced by LISTFILE should be examined, especially, those that sort CMS EXEC files by data or file size.
The QUERY DISK command has been completely changed. See the QUERY
command in the VM/SP eMS Command and Macro Reference manual for more
information. Several other commands have been changed. Programs that examine spooled con­
sole output for the typed results of certain commands might require changes.
Coexistence of VM/SP CMS and Earlier Versions of CMS During conversion from an earlier version of CMS to VM/SP it might be desirable,
depending on local conditions, to run both versions of CMS for a period of time.
However, it is important to remember that system modules from earlier systems
should never be executed on the VM/SP system and vice-versa. Such modules are
incompatible and will damage system and/or user data if run in the incorrect envi­
ronment. Among others, consider the following points to allow easier switching
back and forth between versions: 308 VM/SP System Programmer's Guide
All disks should be formatted with earlier versions of CMS or by specifying a
blocksize of 800. No extended format disks should be used.
All use of the TAPE command should be from the earlier version of CMS or
should specify a blocksize of 800. Programs or EXEC files that reference eMS EXEC files, or programs that ref­
erence or change system control blocks, require special handling. One of the
following actions should be taken:
Segregate such programs or EXEC files onto separate disks (one per CMS version) and access the one that corresponds to the CMS version you are
currently using, or