Cannot upgrade from Multimedia SuperMemo
Question:
Eryk H. asked: I have been using Extreme English DVD for some time. When I tried to ugrade it from Multimedia SuperMemo to SuperMemo 2004, the upgrade collection is messed up (not usable)
More information needed
messed up (unusable) is not sufficiently specific; please submit your collection; you can do it via e-mail (up to 10MB zipped) or upload it anywhere on the net and send the link (to compress Advanced English down to 10MB, omit the huge \elements folder that is less likely to be the cause of problems)
Outline of the Answer:
The submitted collection was corrupted. Either its upgrade to SuperMemo 2002 was aborted, or its files used in SuperMemo 2002 or 2004 were copied onto the original collection used with Multimedia SuperMemo. The collection would behave normally in SuperMemo 98 or Multimedia SuperMemo because the registry files with the extension MEM play no role in those SuperMemos. Only upon an upgrade to SuperMemo 2002 or 2004, the collection would misbehave. By a lucky shot, you can still recover by deleting all *.MEM files from the registry folder before the upgrade. This is a coincidental solution as aborted upgrade, aborted recovery, or copying collections one over the other usually result in a "file chaos" where collection integrity is unlikely to be restored.
(imagine the outcome of your Windows XP folder being overwritten with files from Windows 95, even though Windows as an operating system has a far greater control in protecting files from being overwritten)
Technical:
SuperMemo is "aware" of possible problems at upgrade. Some users still do a criminal Ctrl+Alt+Del on long-lasting upgrade/recovery processes. In addition, a power failure or other crashes are possible during those sensitive processes, and not everyone is patient to keep the backup option checked at upgrade.
For this reason, during an upgrade, SuperMemo does a file housekeeping by comparing a file list with the database structure number stored in the KNO file. Because the list is very long, only the most likely problem cases are resolved this way. Unfortunately, cleaning up of leftover registry *.MEM files was added only after the release of SuperMemo 2004, and SuperMemo still could not cope with this particular case.