Richard,

There have been times in the distant past when CP or CMS command syntax 
changed, and rather than make all the users search for EXECs that needed 
changes, as a sysprog performing the system upgrade, I searched them all 
to see which few actually needed to be changed.  I would not want a 
sysprog-inspired search to affect the last-referenced date.

Sometimes, I've had to scan user control files for specific strings (in 
the long past, sometimes PROFS notelogs).  Again, the files were not being 
used by an application, and should not have the DoLR updated.  Can you 
imagine if backup products caused the DoLR to be updated every time a file 
was backed up or restored?  Might as well just remove the file 
date/timestamps altogether!  ;-)

There were a *LOT* of file searches performed in preparation for Y2K; 
again, the user/application was not affecting those files and the DoLR 
should not be updated.  Sysprogs often have a different role to perform 
and should do their level best to ensure that their work does not affect 
other details.

Mike Walter
Hewitt Associates
Any opinions expressed herein are mine alone and do not necessarily 
represent the opinions or policies of Hewitt Associates.




"Schuh, Richard" <[email protected]> 

Sent by: "The IBM z/VM Operating System" <[email protected]>
07/23/2009 12:50 PM
Please respond to
"The IBM z/VM Operating System" <[email protected]>



To
[email protected]
cc

Subject
Re: Find command






I thought you were talking about real files, not programs :-) Besides, 
there is no such date for files stored on minidisks, so it is essentially 
useless in that regard. For EXEC usage, I tend to look at the statistics 
created by my Global REXX Exit, rather than a reference date. 
 
How would one differentiate between scanning a file in a Pipeline and 
performing the same scan by opening it in XEDIT and using the LOCATE 
command? How about copying the file to another location? What constitutes 
a "real" use from one that does not count? It could be argued that any 
OPEN of the file is a reference. Is not that  the difference between a 
Last Reference timestamp and one for Last Update. 
 
Perhaps if the date were maintained for all files and a line could be 
drawn separating the real uses from the casual ones, don't forget that is 
is possible for the reading of the file to be a real use, I might agree 
with you; however, I think that drawing that line will be very difficult. 
Perhaps you can get a parameter added to FSOPEN and all other macros and 
routines that open files (OS Simulation comes to mind) to indicate that 
your opening of the file is casual and should not count. (That or you 
could maintain a registry associating programs with files ala Windoze. ;-) 
)
 
I am content with letting the scan be counted as a reference. After all, 
the file is being read for some purpose. You are trying to differentiate 
between purposes, and that is something that cannot be determined by the 
system. It only knows that the file has been opened. 
Regards, 
Richard Schuh 
 
 

From: The IBM z/VM Operating System [mailto:[email protected]] On 
Behalf Of Kris Buelens
Sent: Wednesday, July 22, 2009 11:39 PM
To: [email protected]
Subject: Re: Find command

>What is the harm in updating the reference date when one peruses a file 
to see if it contains specific data strings? 
If one uses the last reference date to see if a file (e.g. a program, REXX 
exec) is still being used, such a scanning process should not update it. 
It never is a "real" use.  At the other hand, we had a discussion with SAS 
several years ago: they used OLDDATEREF, and running SAS programs surely 
is "real" usage.
GETFILES will not use OLDDATEREF, it has no parameters, and OLDDATEREF 
would never be a good default.

Kris Buelens
IBM Belgium, VM customer support




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