syncing two pcs

[Mike or Penny Novack]

>a typical scenario.
>
>Start with original document O.
>
>Arnold edits it and gets document A.
>Beth edits it and gets document B.
>
>Now we need to merge.
>
>CVS will calculate which lines have to be insertedm deleted or replaced 
>to make document O into A.  It then does the same to figure how to 
>convert O into B.  THen it applies both sets of changes to convert O 
>into C, which is the merged document.
>
>It fails when the two sets of changes conflict.  In this case, Arnold 
>and Beth will have to reconcile the conflicts by hand to get a 
>consistent document.
>  
>
It fails (can fail) even when there is absolutely no "conflict" in the 
sense you imagine. Rather than use a text example (where meaning totally 
changes) or a coding example (program with merged changes no longer 
works though both tested fine before) we'll stick to accounting.

Company Wigito is in the business of selling widgets. At the start of 
business on day 1 the bank account shows 10,000   sales so far are 1000 
and the widget inventory is 20.  Imagine that Arnold and Beth are both 
recording activity. On this day they BOTH enter the transaction to 
record that 2 widgets were sold for a price of 100 each.

At the end of the day we merge their resulting books* (see below). What 
will cash, sales, and the inventory of remaining widgets show? What 
SHOULD those values be?

Please note that part of the problem is that

Michael D Novack, FLMI

* of course what SHOULD have been merged was not the books after entry 
of the transactions but the "activity" before being entered and then 
that result entered. Designing this sort of system is what they used to 
pay me for -- or more frequently, deal with the crisis when some 
programmer put in a solution that worked " ALMOST all of the time".