PASSWORD SYSTEM EMPLOYED IN SUPER-MEMO SOFTWARE
                        (Aug 15, 1991)

In consequence of insufficient legal protection of copyrighted materials,
SuperMemo World decided to employ software protection of its products in
the form of a password checking system.
The password protection pertains to SuperMemo software release 5 and 6,
and does not concern SuperMemo shareware.

The password checking procedures are activated periodically, not more
often than once a month per single SuperMemo database.
Passwords are unique for different registered users and for different
months.
At the moment of purchase the user obtains an initial collection of
passwords for a limited period, and the remaining passwords are mailed
periodically until the expiry date (if any).
Each times a collection of password is handed or mailed, the deadline for
mailing the next collection is determined as 3 months before the due
date of the first missing password.
For example, if passwords comprise the months January 1992 through
December 1992, the due date of the first missing password is January 1993,
and the deadline for sending it is the end of September 1992.
If for any reasons, the due passwords are not delivered before one month
after the sending deadline, please contact SuperMemo World immediately.
In case of address change, please send a note to SuperMemo World at least
two months before the sending deadline for the next collection of passwords.
For the address change to be valid do include the following:
    - your registration number
    - your old address
    - your new address
    - the date on which the change comes to force
    - last password of your recent collection of passwords with the
      month on which it will be asked.

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       SUPER-MEMO WORLD
       Os Przyjazni 15-165
       61-688 Poznan
       POLAND
       tel (48) 61 203157