[DUG] Licencing schemes

[Paul Heinz]

John asked:

> I like this scheme - I have done something a bit like this with locking
> before (not your way though), but it did suffer from one problem, on a
> Windows network if a program crashed/was terminated/ or the PC rebooted,
> sometimes the locked block on the server was not cleared.  Sometimes would
> clear after some time, sometimes had to be cleared manually on the server
> (Administrative tools/open files). I think it is a caching issue.
>   Did you ever have such problems?

Yes - it happens occasionally but far less than it used to since it's
essentially a server side issue. The server basically just tracks all file
locks in memory (which is why they are transient across restarts) and it
depends on how good it's protocol is for sending heart-beat pings (or
similar) to determine when a client has disappeared and resources should be
cleaned up.

DOS and Windows for Workgroups weren't great for that (suprise!), but NT and
later are fairly aggressive on session handling. There still seems to be the
odd race condition gremlin (it's a Microsoft OS after all :-) and
occasioanally servers get confused and don't notice that a machine has
rebooted but it's pretty rare in my experience and we have many 1000s of
users out there using this technique all day, every day.

> Other musings:
> As far as concurrent or per seat licences go, I take your point.
> One of the
> programs is used all the time (that is they open it and leave it
> running) on
> all screens that want to use it anyway, so concurrent and seat
> licences end
> up being the same in this case.

Yes, spot on.

> Mind you concurrent also can mean two things - the program is
> always opened
> on the desktop, but only active when they are actively looking up data -
> which do you choose as the concurrent user (program open but in background
> or active).  That also is an issue for developers and marketers to choose
> too!

We do concurrent as in 'application open and system database logged into'.
Getting fancier than that costs time and money to code and just costs you
revenue - not a winner in my book :-)

Also, application open is easier for customers to grasp - if you can't
explain your licensing system in a few paragraphs or a few sentences, you're
just making it harder for you and your customers. And yes, that's more a
marketing consideration than a technical one but marketing considerations
are rather important :-)

TTFN,
  Paul.