[Info-vax] Use of logical names other than I/O redirection

[Bob Gezelter]

On Tuesday, September 13, 2022 at 3:58:47 AM UTC-4, Marc Van Dyck wrote:
> Arne Vajhøj has brought this to us :
> > 3) Logical names does not scale well. 50 fine, 100 fine, 
> > 200 fine but 100000 does not work. Windows registry is 
> > a fine example of something that has become so big that 
> > it is difficult to find things. 
> >
> Not if you use separate, dedicated logical name tables. Putting 
> everything in LNM$SYSTEM is of course not good practice, but desiging 
> applications to use their own table(s), use rights ids to grant access 
> to them, and connect automatically to the right tables at login time 
> works perfectly for me. We also use such mechanisms for our development 
> environment, so that each version of each application gets its own 
> set of tables. 
> 
> -- 
> Marc Van Dyck
Marc,

Concur. Did DECUS presentations on those techniques a long time ago, circa 2000. With conventional logins, rights identifiers work quite well, it is effectively parallels access badges. 

Inserting logical name tables into the search path is documented, and removes the need for the application to be aware of the underlying structure. One can also use indirection, e.g., the application-specific logical names hinge on another logical name. For an example, consider SYS$SYSTEM, which references SYS$SPECIFIC and SYS$COMMON, which in turn reference SYS$SYSDEVICE. There is no requirement that they all must be in the same logical name table.

At one client, that little "trick" eliminated thousands, or possibly tens of thousands of process logical names across the active sessions. Realtime performance improved; paged pool decreased, and login-time was significantly reduced. The number of logical names per logged-in user went from hundreds to less than ten.

- Bob Gezelter, http://www.rlgsc.com