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.TITLE DSM - Disk Storage Monitor
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OVERVIEW
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DSM provides a method of keeping check on disk storage. At A.R.A.P. casual
reminders to users to clean up directories has proved to be ineffective
in preserving a resonable amount of free space on our RP06's. Users seldom
take the time to remove unwanted or little used files. A few
weeks after cleaning up we would find ourselves with only 5000 free blocks.
DSM makes daily checks of disk allocations and
automatically reminds users when allocations are exceeded.
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Disk allocation limits are specified on the basis of a uic or group of uics.
Allocations are checked once daily at A.R.A.P. Enforcement is
accomplished via messages at login, purging accounts, or revoking
privileges (refer to memo8a on [360,215] for a detailed description of
enforcement procedures).
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DSM has proved effective in keeping reign on our disk space.
Users generally comply with only warning messages, the threat of more
severe penalties being enough to prompt users to keep disk usage
within bounds.
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MECHANISM
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DSM began as a faster way to do DIR/SUM [*,*], which under PIP can take
up to 2 hours on RP06 packs. DSM gathers and totals block usage on a
directory basis, rather than by file owner. It was done this way
simply because it better  suits A.R.A.P.'s uic structure.
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The summation is done as follows. All directories on a particular
volume are scanned and a map file generated which indicates which
file ID numbers (file headers) belong to which uic's. Then INDEXF.SYS
(file header file) is read sequentially while the generated uic map
file is simultaneously scanned. When a uic is found the blocks allocated are retreived
from the corresponding file header in INDEXF.SYS. When the end of the index file is
reached all directories will be totaled up.
Now all that remains is to check the totals against allocations and
take the appropriate action.
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INSTALLATION and OPERATION
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Installing DSM consists of 3 steps:
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1.##Compile/assemble and build DSM.TSK
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Use the PDS command file DSMBLD.CMD for this.
Install DSM.TSK as $$$DSM under uic [1,1].
Note that DSMPR2.MAC checks that 'DSM' is what appears on the command line.
Modify DSMPR2.MAC if you want to change the name to something other than
'DSM'.
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2.##Compile and build NOT.TSK
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NOT is the notice task which will be run when a user logs in.
Normally ...PIP is used to print NOTICE.TXT. NOT is substituted in
the PDS login module. Step 3 applies the patch to PDS.
See notes below for more on what ...NOT does.
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3.##Apply the patch to the PDS login module.
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Copy ARAPLOGI.CMD and ARAPLOGI.PAT to [11,100].
This patch procedure uses PAT with checksums, and should be reliable.
See comments in the patch command file.
ARAPLOGI.CMD will extract the login module from PDS.OLB and patch it
with ARAPLOGI.PAT, resulting in ARAPLOGI.OBJ;2.
Do not put ARAPLOGI.OBJ into the PDS library!
Edit PDSODL.ODL so that the patch login module will be linked into PDS.
Change the line
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O1170:##.FCTR###LOGI-[11,100]PDS/LB:LOGI
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############to
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O1170:##.FCTR###LOGI-[11,100]ARAPLOGI
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Re-build PDS and then re-install it.
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DSM should now be ready to use. It is used in two modes. If it is
run as a timesharing task it will give a summary of the requested
directories. Syntax is:
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DSM dev:[uic1]+[uic2]...+[uicn]
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Refer to memo8b on [360,215] for more details.
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If it is run as a realtime task DSM will check disk allocations. DSM
determines whether or not it is realtime by a GETMCR failure. If it
is running realtime it will sum all directories on the devices
specified in the DATA statement in DSMMN.FTN (change IDEV and MAXDEV
to be appropriate for your system). DSMMN.FTN is currently set up
to look at DB0: and DB2:. The maximum number of directories per
device is currently set at 300. Change the dimension of ISTAT in
DSMCM.COM and MAXUIC in DSMMN.FTN if this is too small for your application. Recompile and build DSM if
DSMCM.COM is changed.
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FILE USAGE
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DSM uses 4 files on LB0:[1,1] for the disk allocation checking.
Only the allocation specification file need exist to run DSM in
realtime (checking) mode for the first time.
The other three files will be generated by DSM.
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DSM.DAT - this is the allocation specification file. A template copy
is included on [360,215]. Tailor it to your needs.
This file was formerly called DSMALSP.DAT.
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DSM.LOG - logs DSM checking activity and errors. A sample DSM.LOG is
included on [360,215].
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DSMMSG.DAT - This keeps track of the number of warnings an account
has received. It checksums the allocation specification record to
make sure that the specification has not been changed.
If the specification has been changed, the warnings are set back to zero
and any revoked privileges will be restored.
DSMMSG.DAT also contains the privilege mask at the time privileges  are revoked.
Privileges can then be properly reset when disk usage falls within limits.
For this reason, DSMMSG.DAT should never be deleted if any of the UPF
privilege masks have been modified  by DSM. The privilege mask for revoking
privileges is IRVMSK in DSMCM.COM. Change to suit.
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DSMNOT.DAT - This file contains the summary information for all uics
and all devices (specified in DSMMN.FTN)
and any allocation warning messages that a user will receive upon login.
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NOTES
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The patch to PDS forces ...NOT to be run every time a user logs in,
even if the /NONOTICE switch is used. ...NOT examines the command line
passed to it to see if it was /NONOTICE. If so it does not print
the notices. Note that BATNOTICE.TXT will never be used as it is used
as a notice flag on the command line. Also NOT.FTN suppresses any
batch notice printing to speed login in batch (normally there
is no way to suppress notices during batch login). NOT retreives the
users default uic from the command line and searches DSMNOT.DAT to see
if there are any warning messages to be typed out for this user.
 If there is a message, it is
printed along with the disk utilization numbers for his uic.
If /NONOTICE was specified, and there are no warnings to type, ...NOT exits. Otherwise, disk
utilization numbers for this users will be displayed.
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We schedule $$$DSM to run every 24 hours at 5:00 am.
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RUN/INT:24H/SCHED:05:00:00/UIC:[1,1]/PRIO:110 $$$DSM
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The warnings (if there are any) are incremented each time $$$DSM is
run (realtime). Therefore if scheduled to run twice a day the
enforcement rules will be applied in half the time span. E.G., message _#8 triggers
the next step (PIP /PU etc.) which normally allows a week for a user
to clean up before files get deleted. If $$$DSM is run twice daily, this would
only allow 3.5 days before message _#8 and its consequences would be reached.
The warning _#'s at which the next level of action takes place
can be changed by editing DSMCM.COM and changing IDLLIM (delete limit)
and IRVLIM (revoke limit).
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DSMUSERS on [360,215] reads PDSUPF.DAT and lists all users and their
default uic in alphabetical order. Output is to unit 6.