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Conference azur::mcc

Title:	DECmcc user notes file. Does not replace IPMT.
Notice:	Use IPMT for problems. Newsletter location in note 6187
Moderator:	TAEC::BEROUD

Created:	Mon Aug 21 1989
Last Modified:	Wed Jun 04 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	6497
Total number of notes:	27359

600.0. "Coherence in the way FM's work." by CCIIS1::ROGGEBAND (_ �hili��e _) Wed Jan 09 1991 08:01

    Hello,
    
    A comment about a difference in the way the Domain FM and the Alarms FM
    work. 
    
    When a domain is created, we have to specify a directory in which
    repository files will be located. The domain FM does not check if the
    directory exists. Unfortunately, if we mistype the directory name, and
    realize this after populating the domain, the directory attribute is
    not settable;.
    
    When an alarm rule is created, we can specify a DCL procedure which
    will be activated. The ALARMS FM checks if the .COM file exists, and
    even memorizes the version number of the .COM. Again, the name of the
    procedure is non-settable. This leads to problems if the command file
    has to be edited. I know is it is possible to rename the file so its
    version number coincides with the procedure specified in the alarms
    rule.
    
    This leads to two questions :
    
    1) Why are the direcctory / filename attributes defined as
    non-settable?
    
    2) For coherence's sake, shouldn't ALL FM's either check for directory
    / file existence, or not check, rather than having each FM do its own
    thing?
    
    best regards,
    
    Philippe.

T.R	Title	User	Personal Name	Date	Lines
600.1	About ALARMS	TOOK::ORENSTEIN		`Wed Jan 09 1991 13:55`	27
	Hi Philippe, Thank you for noting that the two FMs handle the use of files differently. I will look into trying to make things a little more consistent. In the mean time, I can tell you why ALARMS check for file existence and saves the version number: During the design process we recieved input concerning security. It was thought at the time that someone trying to sabotage security could easily replace a notification command procedure with one that turned on privileges and did harmful things. This is also the reason why we use MCC_ALARMS_SECURITY to normalize the environment before the notification command procedure is run. Even here in the development world, we realize that having to re-create your rule, or fix up version numberbers because you made an edit to your notification procedure, can be a pain. We are hoping to provide a SET directive pretty soon. This could be used to SET any of the arguments to the CREATE RULE directive. aud...
600.2	This is not necessarily secure...	ULTMAT::BELANGER	A ROSE by anyother name, would not be manageable	`Thu Jan 10 1991 12:25`	9
	RE .1 This is not necessarily secure. If someone can write to the device with a new version, then they should also be able to rename the old version and copy a replacement version specifying the correct version number for ALARMS to find the file. ~Jon.
600.3	How about just discouraging	TOOK::ORENSTEIN		`Fri Jan 11 1991 10:48`	11
	Jon, It's true that this is not secure. Infact, what you have described (renaming new version to old version number) is the only way to use a new version of the command procedure without having to create the rule again. It's not secure, but it is pretty discouraging. aud...
600.4	Domain directory setting and checking	TOOK::A_MOORE		`Tue Jan 15 1991 16:20`	17
	If Domain FM could set the directory attribute it could pull the rug out from under the XM's that use it, such as the Historian. Other modules that I have not even heard could be effected. In the future, there will be methods that will be used to inform other modules that a change has taken place. VMS specific Directory checking was removed from the Domain FM for flexibility. Many directory features such as VMS logicals, DFS, NFS, [], / and etc. are not portable. We need to solve the problem of how check multiple directory syntaxes from multiple platforms both ways. In addition to the operating systems syntaxes there are Network datastore syntaxes such as DFS and NFS. So keeping it very simple avoids these problems. The COPY DOMAIN command could used to easily create a new or temporary domain with the directory you really meant to type. Both of these items are on the wish lists, having been previously traded off.