A station that was away — a laptop that lost the network, one that was
switched off — comes back missing whatever the others logged while it was
gone. N1MM fills that in by walking the log an hour at a time, and this is
that walk, on the same messages:
| Message | What it says |
|---|---|
| `CHECKSUM` | here is what I hold for your contacts in this hour, and the contest and callsign I am logging |
| `DELETEQS` | drop your copies of my contacts in that hour, I am sending them again |
| `RESYNCQSO` | one of those contacts |
| `CONFIRMED` | here is what the hour hashes to at my end — which also asks for the next hour |
Each station is the authority on the contacts it made, so an hour that
disagrees is replaced rather than merged. The answer to one block asks for
the next, and the walk ends when the block starts after the end of the
period. The Resynchronize tab counts the hours that agreed, the hours that
were sent again and the hours that still disagreed, which are N1MM's
columns.
**`LogChecksum`** is N1MM's: a CRC32 over the `DXLOG` columns of the block,
ordered by time and then callsign, leaving out what each station works out
for itself — points, the three multiplier flags, the country prefix, the
continent, the WPX prefix and `IsOriginal`. Two stations may disagree about
those and still hold the same log. A checksum that disagrees for any other
reason costs one block of traffic, which is what a resync is for.
**The link still holds no log.** It asks one through `ContactLog` for the
contacts of a computer in a block of time, and `SessionContactLog` answers
on the window thread, because that is where the log is touched.
**Every contact logged here now carries the computer that made it.** N1MM
stamps `NetBiosName` and `NetworkedCompNr` on every row and this program
did not, so its own contacts belonged to no station and a resync could not
ask for them.
**Rescore** writes the points and multiplier flags of a period back to the
database. The log in memory scores itself whenever it changes; the stored
rows do not, and N1MM reads them rather than working them out. A contact
that arrives from another station after the one that took a multiplier
leaves those columns behind. A station can also ask the others to rescore
when its resync finishes, which is the flag on the end of `CHECKSUM`.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PdAYHcdRktqKry7nk414TU
AppSession.TakeFromNetwork wrote the contact to the store and then called
OpenContest to see it, which built a new ContestSession, read the whole log
back and built new entry positions. Anything the operator was typing at either
radio went with them, and the entry boxes were rebuilt under the other
operator's hands. It also ran on the socket thread, so it was changing the log
while the windows were reading it.
ContestSession now applies the three messages itself: AddFromNetwork,
ReplaceFromNetwork and DeleteFromNetwork write the store, change the log in
place and raise Changed. None of them raises Logged, Edited or Deleted, so
nothing goes back out to the other stations. Points and multipliers are still
worked out here from the rules rather than trusted.
A contact that arrives goes in where its timestamp says it belongs, through
the new ContestLog.Insert, and the log is scored again: of two stations that
worked the same multiplier, the one that worked it first keeps it, however
late the message turns up. Add would have appended it at the end and given the
multiplier to the wrong contact.
The socket thread now hands the update to the thread the windows run on, which
is where every other change to the log is made.
The matching rule moved with the code, so ContestSession answers what a
message from N1MM refers to: the contact id, then the call and time it had
before the edit.
Still not tested against a second station. Two of these cannot run on one host
to try it, because they share one UDP port.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RoGtneMQaz4M9w7Kk49AVD
erikbrockoandClaude Opus 5