[Info-vax] OpenVMS - DCL - Data entry filtering

[David Froble]

JF Mezei wrote:
> On 15-03-29 18:03, Stephen Hoffman wrote:
> 
>> MAIL is a (good?) (bad?) example of what happens when you don't have a 
>> modern database, when you do have to work within the limitations on how 
>> fast you can scan directories (and this also from within a 
> 
> 
> But MAIL was originally designed like NOTES, with the expectation that
> most messages would be stored in the main indexed MAIL.MAI file.
> 
> The size limitations that triggered external storage were fine
> originally, but once just about every internet email exceeded that size
> limit, the mail store morphed into something it had not been designed
> for with every email stored externally.
> 
> 
> ALL-IN-1 had an interesting design. Created a database of email documeht
> attributes with pointer to random filename stored in a "random"
> directory. It was designed that way to distribute the tousands of files
> amongst a number of directories to avoid the performance problems of
> large directories.
> 
> It also had the advantage of having 1 copy of an email sent to multiple
> recipients. Each had a pointed to the shared copy. It only got deleted
> when the shared count dropped to 0.
> 
> Note that Unix mail stores are not exactly very efficient either. But
> they seem to work and scale.
> 
> dovecit for instalce uses strange file names on OS-X for each message:
> "1404580067.M555292P14187.velo.vaxination.ca,W=2670,S=2621:2,RSa"
> 
> But it files message files in folders that correspond to IMAP folder
> names. and there is some binary index to each file.
> 
> 
> VMS designers have to decide whether to go with the flow and just make a
> file system very efficient for large number of files (turning the file
> system into a database) or  provide database tools that allow apps to
> store large number of "things" in a single file instead of one file per
> "thing".

Ok, so I'm a bigot.  So what?  Doesn't mean I'm wrong ....

Quite a bit (most) ((all?)) of the blame should be heaped on the 
developers who will design an application to flood the file system with 
so many files.

Quite often, the question "why did you ever do that?" is appropriate.

As others have noted, a file system makes for a poor database ....