[Dxspider-support] Enabling Q:1 spots

[rin JG1VGX]

My reply continues ...

> - finally got the gist that a single 'acc/ A' and a 'rej/ not A' mean the same, but multiple 'acc' filters works like additive (A OR B) while 'rej' works like multiplicative (A AND B).
> - if no /rbn filter is defined, /spots filters apply for both regular and RBN spots. But once any /rbn filter is defined, filters must be defined separately for both regular and RBN spots.
>
> Please do "help filter" or read it on the wiki. It's meant to be "intuitive", but then it would be - to me. It's not quite as you describe it. But in essence it's this:
>
> 0. If there is no filter for this "thing" then nothing is filtered. It is just passed on.
> 1. For every type of thing you can filter (spots, announcements etc) there as 10 filter slots.
> 2. You can have a different filter in each slot.
> 3. Each slot is tried in the order 0 -> 9. This is "ladder logic".
> 4. Empty slots are ignored.
> 5. For every slot that matches: if it is a REJ filter it immediately rejects that "thing"; if is an ACC filter it will accept that "thing". No further processing on that "thing" occurs for that filter.
> 6. REJ filters are tried first; if it falls out of the bottom then the ACC filters are tried and if it falls out of the bottom then that "thing" is rejected.
>
> The point of this is that nobody gets negative logic right the first time (nor the second or third time) however good one might be. Hence the REJ filters - they throw away everything you DON'T want. The ACC filters (only) give you what you DO want. You are therefore using positive logic to get what you want (much more of the time).

Yes, I read those but 'acc', 'rej' and 'ladder' logic is still a
little hard for me to take in.
I tend to think more in logic expressions, eg. A OR B, A AND B etc,
when I think about filters. Then I have to translate them into
negative ladder logic which is a little pain.
Apparently most users at my nodes don't use filters at all. If they
do, only a single or couple of filters. Logging software like N1MM
Logger+ has a no-brainer GUI filtering panel that makes filtering at
telnet source almost unnecessary.

Here are my logic translation examples. Please correct me if I'm wrong.

A OR B
 Filter1: acc/ A
 Filter2: acc/ B (or rej/ not B)

A AND B
 Filter1: rej/ not A
 Filter2: rej/ not B (or acc/ B)

A OR B OR C
 Filter1: acc/ A
 Filter2: acc/ B
 Filter3: acc/ C (or rej/ not C)

A AND B AND C
 Filter1: rej/ not A
 Filter2: rej/ not B
 Filter3: rej/ not C (or acc/ C)

A OR (B AND C)
 Filter1: acc/ A
 Filter2: rej/ not B
 Filter3: rej/ not C (or acc/ C)

A AND (B OR C)
 Filter1: rej/ not A
 Filter2: acc/ B
 Filter3: acc/ C (or rej/ not C)

Apparently, "acc/ X" and "rej/ not X" in the last slot have exactly
the same effect. So if you mentally ignore the last filter, you'll see
that a combination of an operand and the following operator, eg. "A
AND", "B OR", immediately translates into "rej/ not A", "acc/ B" in
the table above. Since the last operand has no trailing operator, the
last filter can be either way.

For me, these filter logic is hardly intuitive. It is as easy as Perl
or regex syntax ;)

But I am yet to find the translations for these more complex filter logic's.
  (A AND B) OR (C AND D)
  (A OR B) AND (C OR D)
Perhaps not possible??

> As we are all consenting sysops here, you should be made aware of the implications of input filters on your feeds (or node_default file for that "thing"). Any input filter will affect what gets into your node for onward processing. It is dumped at source. BTW a more efficient way of reducing what your users can see is to rcmd/<node partner> acc/spots by_zone 1,2,3 (for instance) and your node will never see any spots from spotters in other zones. Saves a lot some bandwidth.

Thank you. I do not use node_default filters for route filtering.
Japan has no regional network and each cluster is alone in the world
(wild). I have many peer nodes but they are just backups and I made
them all 'passive' connections using "acc/route" filters described in
the manual. My only active upstream connection is with VE7CC-1 CC
Cluster.

Dirk-san, thanks again for your time and dedication to this software.
I'm very happy to be a part of this community. I am still learning!

--
73 rin JG1VGX