[Info-vax] Why does this DIFF command fail, then run fine the 2nd time around?

[abrsvc]

On Monday, December 12, 2022 at 7:26:54 PM UTC-5, Dave Froble wrote:
> On 12/12/2022 5:24 PM, Stephen Hoffman wrote: 
> > On 2022-12-12 21:18:18 +0000, Dave Froble said: 
> > 
> >> On 12/12/2022 1:27 PM, Stephen Hoffman wrote: 
> >>> On 2022-12-12 06:45:44 +0000, alanfe... at gmail.com said: 
> >>> 
> >>>> $ DIFP SCRFELD:[.A.TO_V530]CLEAR_NBACK_LNMS.COM;1 [.B.*] 
> >>>> ... 
> >>>> $ SHOW LOG/FUL SCRFELD 
> >>>> "SCRFELD" [super] = "DSA2:[USR_SCRATCH.FELDMAN.]" [concealed,terminal] 
> >>>> (LNM$PROCESS_TABLE) 
> >>>> $ 
> >>> 
> >>> AFAIK, usual preferred command syntax with a concealed rooted logical name 
> >>> would be thus: 
> >>> 
> >>> DIFP SCRFELD:[A.TO_V530]CLEAR_NBACK_LNMS.COM;1 [B.*] 
> >>> 
> >>> Trailing dot (from the logical name, correctly) and leading dot (from the 
> >>> appended directory) passes along some variation of [TOS..A] and [TOS..B]. 
> >>> 
> >>> Looks like a dusty corner within the name and default name and related-spec 
> >>> parsing, among other dusty corners within filespec parsing. 
> >>> 
> >>> Shouldn't blow up, but arguably also probably shouldn't work. 
> >>> 
> >> 
> >> Some people are way too fond of rooted logical names ... 
> > 
> > There are some people too fond of logical names, too.
> Ayep ...
> > Though this case looks more like filename parsing gone awry.
> It's the other side of lots of flexibility, many options,some might claim too 
> many options.
> > Wouldn't be the first time there was a bug in filename parsing either, as 
> > somebody else (A.M.) once remarked. While debugging a parsing-related error.
> The rooted logical stuff is interesting, but, sometimes just because one can do 
> something, doesn't then mean that they should do it. 
> 
> The early developers wanted multiple OS roots. Ok, maybe that might be Ok. But 
> then others took the concept, and used it where it just wasn't needed. They did 
> it because they could. Reminds me of "the road to hell is paved with good 
> intentions" and other such.
> > OpenVMS filename syntax is... baroque.
> Don't make me look up that word ... 
> 
> :-) 
> 
> I have no problem with the basic filespec stuff. I actually prefer the 
> "[a.b.c]" directory specification over "/A/B/C", but I do understand the latter 
> might be easier to parse. Don't know, never used it much. Don't like it.
> > More baroque in recent years, in service to continued app compatibility.
> If apps don't get "tricky" then perhaps compatibility might be easier.
> > DIDing, FIDing, ^U, mount points, what's implemented in the CRTL and what's in 
> > the XQP, etc.
> Ok, opinion time. The CRTL should deal with C stuff. VMS stuff has no place in 
> the CRTL. Just my opinion. Originally VMS stuff had System Services, LIB$, 
> etc. Then someone got lazy.
> -- 
> David Froble Tel: 724-529-0450 
> Dave Froble Enterprises, Inc. E-Mail: da... at tsoft-inc.com 
> DFE Ultralights, Inc. 
> 170 Grimplin Road 
> Vanderbilt, PA 15486
Without getting too far off into a tangent...

There are uses for rooted directories not only for the OS and clusters, but also for the installations that have multiple user groups and require some level of separation as well as common files.  I have used this method along with group level and names logical name tables to isolate specific clients from each other while still maintaining common executables and procedures.  As with any "feature", it can be abused but can also be an asset when used proper

Dan