Each SuperMemo database contains four files with extensions .INF, .ITM, .ITI and .DAT. These files are created automatically by Files : New and are updated each time the database is modified. If one of these files is unavailable, opening the database is not possible; therefore, it is recommended that regular backup copies of ALL database files be made.

Content of the database files is as follows:

<name>.INF - information about the learning process. For example: Total, Memorized, Intact, Burden, E-factor distribution, Interval distribution, OF matrix, RFmatrix, forgetting curves, Lapses (requested and measured), etc.

<name>.ITM - text of items

<name>.ITI - information about items. For example: interval, e-factor, u-factor, repetition, lapses, last repetition, pointer to the item text in the ITM file, pointer to the next intact item, pointer to the next item scheduled on a given day, etc.

<name>.DAT - list of pointers to lists storing items scheduled for particular days

Note: Modifying the above files in any other way than by means of tools provided by SuperMemo World may result in destroying the integrity of the database,

A database may also optionally include the following files:

<name>.AAA, AAB, AAC, AAD, etc. - bitmap files associated with particular items

<name>.YAA, YAB, YAC, YAD, etc. - sound files associated with particular items

<name>.TTF, FOT - True Type font files (stored in the Windows directory)

<name>.DRL - sequence of items scheduled for the final drill (this file is erased by Learn : Cut drills and can always be deleted without detriment to database integrity)

<name>.INI - database configuration file (desktop, font, color, etc.)

<name>.DOC - text file with the description of the database (this file can always be deleted)

Other files having the same name as the database might include (see TOOLKIT.TXT for more details):

<name>.TXT - text file with the content of particular items and learning parameters (generated by Tools : Export text, TO_TEXT.EXE or TRANSFER.EXE)

<name>.STB - sortable text file generated by database conversion options (Tools menu)

<name>.SRT - sorted text file generated by database conversion options on the Tools menu

<name>.REC - recovery report generated by Tools : Recover or RESCUE.EXE

<name>.CNV - string conversion file used by Tools : Replace strings or REPSTR.EXE

<name>.FLT - string conversion file used by Tools : Export text or TO_TEXT.EXE

<name>.CRS - list of databases used by the database cross-section utility CROSS.EXE

<name>.FND - sequence of items used by search browser (Browse : Searched)

<name>.AUD - list of audio items (used to speed up the option Browse : Audio items)

<name>.VIS - list of visual items (used to speed up the option Browse : Visual items)

<name>.$$$- temporary files that may appear in case of a system crash (they can all be deleted)