Hi mark,

On 2014-04-23 21:18:57, you wrote to me:

 WvV>> First, I have never noticed a false positive. There were false
 WvV>> negatives, when the messages were too old to be in the dupe base.

 ml> what determines the age of "too old"?? simply the number
of entries in the
 ml> database, the age of the post by creation date or the age of the post by
 ml> arrival time??

Number of entries.

 WvV>> FMAIL.DUP      Contains  the database  with signatures  of
 WvV>> messages                used by  FMail to  detect duplicate
 WvV>> messages.  FMail                keeps track of the last 16384
 WvV>> messages.

 ml> wow... understandable to a point... it brings up the question of what the
 ml> records consist of to fill 64K with only 16384 posts...

A CRC32 (4 bytes) per post. 16K * 4 = 64K.

 WvV>> FMAIL32.DUP    The 32-bit version of the duplicate detection
 WvV>> file.                It is  capable of  keeping track of  more
 WvV>> duplicates                than the 16-bit DOS version. (max.
 WvV>> 9999*1024).

 ml> this seems inconsistent with the previous statement... one says "16384
 ml> messages" whereas this one seems to say 9999 messages with 1024 bytes
 ml> (bits?) per entry...

This one is used by the 32bit versions of FMail. The 9999 is the maximum
you can configure in the "Dups recs (x1024)" setting. The 1024 is
not bytes, but entries.

 WvV>> Ignore MSGID

 WvV>>           Normally FMail uses the MSGID of a message (if present)
 WvV>>          for duplicate detection purposes. In some cases, this
 WvV>>       may cause problems when different messages are having
 WvV>>    the same MSGID: one or more of these messages will be
 WvV>> marked as duplicates although they are not. If you are
 WvV>> frequently experiencing these problems, try setting this
 WvV>> switch to 'Yes'.

 ml> that would seem to defeat the purpose of MSGID... especially if FMail is
 ml> expecting the MSGID to be unique across all message areas... in fact, this
 ml> brings up one of the flaws in the MSGID portion of the relevent FTSC
 ml> standard document... there is no specification of uniqueness across all
 ml> message areas or if the uniqueness is per message area... there are several
 ml> well known packages that operate on the "per area" basis
which then causes
 ml> false positives in other packages... for that matter, there are some well
 ml> known packages that maintain duplicate databases on a per area basis
 ml> instead of one attempting to cover all message bases...

That's what this setting is for. If you experience false positives, you can
turn of the MSGID based dupe checking...

 WvV>> Dups recs (x1024) (32-bit mode only, start FSetupX with "/32")
 WvV>>           Number of signatures of messages that are stored on
 WvV>>      disk.

 ml> is this true for all supported OSes? this shouldn't, IMHO, be
 ml> necessary... the tool should be able to detect which environment it is
 ml> running in and use the necessary means/methods/capabilities...

This setting is to specify the number of dupe records used in 32bit
versions of fmail. But since FSetup doesn't know which version of the
fmail.exe program you are using, you will have to specify (on the
commandline) you want to configure the special settings for the 32 bit
versions.

 WvV>> So it depends on the version you are using and your settings. In
 WvV>> the .DUP file a crc32 of some parts of the message (depending on
 WvV>> your settings) is stored. If you want to know more about the
 WvV>> techincal details of that, look in the source:

 ml> thanks... but i asked so that

 ml> 1. non-coders would have a simple straight forward answer

I know you know your way around code. And you asked the question.

 ml> 2. myself and others would not have to try to wade through alien code

You rather have me do it?... My time is limited, and for me the code is
"alien" as well. Time I spend on "support", can't be
spend on development.

Remember I'm not the original coder, so most of the code is still
unfamiliar to me. And I don't know any of the motives of the original coder
why he did the things the way he did them... The advantage of open-source
is, everyone can find out the details for himself, if he is interested
enough.

 ml> then there's the question of does the duplicate detection have any
 ml> effect on the messages being passed on to other systems...

Dupe checking is done before messages are tossed to other systems, as it should!

Bye, Wilfred.

--- FMail-W32-1.68.1.61-B20140411