Hi all

I am writing an app that requires me to only let a certain number of users
log in at the same time.
I am using D5, Firebird and IBO for this.

I have a user name and password that gets used to automatically log into
firebird.
I then have a table with users in it that I use to verify if the entered
user name and password are valid.
When this gets gone I update a flag that says that the user is logged in.
When they log out the flag then gets updated to false.
I use a query to do all this.

1) What I want to do is only allow a certain amount of users to access the
program at once.

2) My other concern is what happens if the machine bombs out and the logged
in flag never gets reset, how do I know if the logged in flag is still
valid.

Any help and suggestions would be much appreciated.