[Info-vax] VMS enhancement suggestion: Add a "read regardless" file open option.

[VAXman- at SendSpamHere.ORG]

In article <549fa5fa-d403-4b3a-a01e-30f611d852c3n at googlegroups.com>, Hein RMS van den Heuvel <heinvandenheuvel at gmail.com> writes:
>On Tuesday, November 10, 2020 at 7:56:11 PM UTC-5, Dave Froble wrote:
>> On 11/10/2020 6:16 PM, Craig A. Berry wrote: 
>> > 
>:
>:
>> Read about the USEROPEN in a file OPEN statement. Basically (sic) the 
>> FAB and RAB (I believe) are populated, then the USEROPEN routine, 
>> provided by the programmer, can set or clear FAB and RAB fields, and 
>> then do the actual file open. 
>:
>:
>> Basic(ally) (sic), it's in there ....
>
>Noop. Sorry. A program doesn't get that far!
>As others indicated, the RRL (read Regardless of Lock) option is RECORD level for your GETs, but RMS will fail the open when the writer did not explicitly grant permission.
>
>Some replies refer to BATCH log file and for those indeed increasing the output_rate will help and indeed DCL could be improved for all to enjoy. Fine, but nothing in the Original Post suggested to me that batch job logs were the main or only concern.
>
>The relative usefulness of the NO_LOCK XQP option can be tested by using BACKUP/IGNORE=INTERLOCK as copy tool.
>You may find that the 'log' writer often does NOT force RMS to update the EOF, leaving it at zero and therefor it will NOT copy anything! My silly program, which Craig kindly found and re-posted here may be able to return more data for some usages.
>
>For occasional/exceptional usage Wizards, and apprentice wizards, would of course use ANALYZE/SYSTEM to just read the last record written straight in user process spaces. Roughly -  
>SET PROCESS XXX
> SHOW PROC/CHAN !-- helpful to match the FAB with the file through STV  when the name is no longer connected to the fab;  SHOW PROC/RMS=FAB ! Find the file desired looking at FNM/DNM and find file number in IFI - for tricky cases: RMS=(FAB,FWA) 
>SHOW PROC/RMS=(NOIFB:a, RAB) ! guess 'a' from relative file number, or from above, NOIFB selects one file only, without displaying IFAB ... which you might need to find actual in memory EOF
>EXAM ufb;usz  ! Display last record using RAB pointer/size. -
>If that's too dynamic, then you may want to look at the last buffer(s).
>SHOW PROCS/RMS=BDBSUM will show start addresses and VBN ranges for the last buffers.
>
>If would require a fair bit of Kernel mode code to turn the above into a program, not impossible (and easier than writing a reliable intercept - right Brian!)  but nobody has done this in a semi productized fashion best I know. Hmmm....

Yeah, a spare time project.

-- 
VAXman- A Bored Certified VMS Kernel Mode Hacker    VAXman(at)TMESIS(dot)ORG

I speak to machines with the voice of humanity.