==========================================================================

                REVIEW OF THE DEVELOPMENT OF THE SUPER-MEMO
                METHOD AND SOFTWARE

==========================================================================

                CALENDAR OF MAJOR DEVELOPMENTS

1982 - Application of the recall principle
1984 - Application of the minimum information principle
1985 - Application of the optimum spacing of repetitions
1987 - First computer implementation: SuperMemo 1.0 (introducing the
       concept of an E-factor)
1988 - SuperMemo 2 and SuperMemo 3
1989 - SuperMemo 4 - optimization based on the matrix of optimal
           intervals
       SuperMemo 5 - optimization based on the matrix of optimal
           factors
1990 - Completing "Optimization of learning. A new approach and
       computer application" (including the model of intermittent
       learning and a comprehensive theoretical analysis of the
       learning process conducted along a schedule determined by
       SuperMemo)
1991 - SuperMemo 6 - optimization based on approximation of forgetting
           curves
       July 5, SuperMemo World was formed
       November, SuperMemo 6 becomes a finalist of the Software for
           Europe 1992 Award Competition
1992 - March, SuperMemo World displays its products at CeBIT '92
       September, SuperMemo 6 receives the first degree award at
           Softarg '92, Katowice, Poland
       September, SuperMemo 6 receives a special award of the
           Polish Computer Science Society
       December, SuperMemo 6 is awarded in the Product of the
           Year 1992 competition organized by PC Kurier, Poland
1993 - January, releasing SuperMemo 7 for Windows
       March, releasing SuperMemo 5 Shareware
       March, SuperMemo World displays its products at CeBIT '93
       May, releasing AudioVisual SuperMemo 7 for Windows
       August, releasing SuperMemo for Amiga
       September, SuperMemo tops the chart of best Polish software
         hits for Amiga (Amiga Magazine)
       September, SuperMemo 7 is awarded at Softarg
       December, SuperMemo becomes the first ever Polish software
         reviewed in Byte International
       December, SuperMemo 7 is awarded in Product of the Year 1993
1994 - January, SuperMemo is voted 4-th most popular Polish software
         by readers of Polish PC World (behind anti-virus and word-
         processing products)
       March, SuperMemo for Amiga is voted the Product of the Year
         1993 among Polish software for Amiga by readers of Amiga
         Magazine
       March, SuperMemo World displays its products at CeBIT '94
       March, SuperMemo is awarded for the best price/value ratio
         by the CENA/VYKON journal, Czech Republic, March 1994
       April, SuperMemo USA Inc. is established
       May, SuperMemo 7 is awarded a prestigious Gold Medal at
         Infosystem Computer Fair in Poznan
       July, 10,000-th copy of SuperMemo has been sold
       August, SuperMemo USA, Inc. publishes SuperMemo on CD-ROM,
         including the audio release of Advanced English best-seller.
         This title becomes the first Polish Windows software title
         on CD-ROM ever
       September, SuperMemo World is granted the special award of
         the fair's president at Softarg and receives a free display
         for 1995
       September, SuperMemo World signs its first OEM bundling deal
         with JTT, second largest computer-maker in Poland
       October, SuperMemo World publishes the European release of
         SuperMemo on CD-ROM
       October, SuperMemo 7.2 tops the ranking of best-selling
         software sold at illegal software market, ahead of
         Microsoft Word 6.0 and Microsoft Works 3.0 (published
         by PC World Komputer, Vol. 11, 1994)
       December, SuperMemo for Windows receives the Reader's Choice
         distinction from PC World Komputer (Vol. 12, 1994) by being
         voted second most popular Polish software in Poland and the
         most popular Polish software for Windows in Poland

==========================================================================

                SUPER-MEMO SOFTWARE

               VERSION 1.0 - Written in December 1987

               CHANGES TO VERSION 1.1 (Feb 88)

       1. Comprehensive help
       2. The lower limit for E-factors set to 1.3
       3. An improved formula for E-factor evaluation
       4. Outstanding parameter in PROCESS INFORMATION used to
          indicate the number of repetitions in the final drill

               CHANGES TO VERSION 1.2 (Mar 88)

       1. TRANSFRM.COM used to convert databases to the intact
          form (later called RESET.EXE)
       2. Applying final drill to newly memorized items
       3. Applying the rule that if an E-factor was equal to 1.3 then the
          quality lower than five decreased the new interval (without
          changing the factor). This solution was later given up as
          inappropriate
       4. Using Home in the INTACT QUEUE (PRIORITY QUEUE) option to
          increase the current queue position to make modifications easier
          (the INTACT QUEUE option was later given up)

========================================================================

               VERSION 2.0 (Jul 88)

       1. Upgrading the program to Turbo Pascal 4.0 (previously Turbo
          Pascal 3.0).
       2. Improved ITEM EDITOR (with commands such as End, Home, Ctrl-Y,
          etc.)
       3. Dates rather than day numbers used to inform the user about
          the process
       4. Screen attributes changed to meet the requirements of
          Hercules Graphic Card

               CHANGES TO VERSION 2.1 (Jul 88)

       1. Simplified and rebuilt menu structure
       2. Source code file shortened by 6300 bytes
       3. Letters instead of numbers used to select options
       4. Option SOUND OFF

               CHANGES TO VERSION 2.2 (Nov 88)

       1. New Help compiled as a separate file

          (SUPER-MEMO 3.0, October 1993, see further)


               CHANGES TO VERSION 2.3 (Jan 89)

       1. Shorter and faster COMPRESS procedure

               CHANGES TO VERSION 2.4 (Sep 89)

       1. New help in a new format (modelled after Borland products)

               CHANGES TO VERSION 2.5 (Jun 91)

       1. Adapting SuperMemo 2 for shareware distribution
       2. Information about SuperMemo World
       3. Simplified system of messages
       4. Help file corrected from the linguistic standpoint
       5. Item editor imported from SuperMemo 5

               CHANGES TO VERSION 2.6 (Feb 93)

       1. Converting SuperMemo 2 to Public Domain software


==========================================================================

             VERSION 3.0  (Oct 88)

       1. The whole program was written again from scratch
          applying the then popular standards of windows, pull-down
          menus and other elements of user-friendly interface
       2. Databases with separate names
       3. Option for editing items during testing
       4. Computing the average quality in Random Test (this option
          was later given up)
       5. Average burden change for a session
       6. Average quality for a session
       7. Option for changing the date
       8. OS Shell option
       9. No intact queue editor

===========================================================================

            VERSION 4.0  (Feb 89)

       1. Improved optimization method: function of optimal intervals
          is modified to adjust it to a given learner and given knowledge
       2. Option for displaying optimal intervals
       3. Option for displaying the number of repetition cases used in
          computing optimal intervals
       4. Option for displaying distribution of intervals
       5. Burden parameter (defined as a sum of inverse intervals)

            CHANGES TO VERSION 4.1 (Mar 89)

       1. Assembly language procedures used to search for items containing
          a given substring (search rushes 1000 items per second: 8086,
          RAM-disk)

            CHANGES TO VERSION 4.2  (Mar 89)

       1. Continuous optimization: In versions 4.0 and 4.1 all items having
          factors from the same class (e.g. 1.4, 1.432, 1.499) were subject
          to the same optimization procedure. Now, each of them has its own
          set of optimal intervals (later this solution was given up)

            CHANGES TO VERSION 4.3 (Sep 89)

        1. A new comprehensive help
        2. Directory system extended to include separate paths for
           databases, parameters, help and COMMAND.COM
        3. Optimized source code used to make the program smaller,
           faster and easier to modify

=========================================================================

             VERSION 5.0 (Oct 89)

         1. A new, advanced optimization technique based on computing
            optimal factors rather than optimal intervals
         2. Option for displaying optimal factors
         3. Option for displaying the approximate values of optimal
            intervals
         4. Storing the last repetition date and the U-factor in the
            database

             CHANGES TO VERSION 5.1 (Mar 90)

         1. Option for printing items in the browsing mode
         2. New recovery mechanisms in the compression procedure
            (option Compress was later renamed to Garbage collection)

             CHANGES TO VERSION 5.2 (Mar 90)

         1. Optimal factors greater than 6
         2. New function for modifying factors on the base of quality,
            consistent with the one used to modify optimal factors:
            quality equal to four does not change the factor
         3. Automatic closing the database before leaving to DOS

             CHANGES TO VERSION 5.3 (Mar 90)

         1. Reset operation in the browsing mode
         2. Date of the next repetition displayed in the item window
         3. Choosing the last-used item in Select instead of providing
            an item number
         4. Inputting grades in the random test no longer necessary

             CHANGES TO VERSION 5.4 (Jul 90)

         1. Full propagation of changes in the OF matrix
         2. Qualities 0, 1 and 2 have the same impact on the optimization


           (SUPER-MEMO 6.0, May 1991, see further)


             CHANGES TO VERSION 5.5 (Jul 91)

         1. Improved procedures for window management, string
            editing, item editing, etc.
         2. Increased database fault tolerance
         3. Introducing mechanisms for preventing piracy (e.g.
            passwords, database marking, registration number, etc.)
         4. Introducing some of the advanced procedures from
            SuperMemo 6

            CHANGES TO VERSION 5.6 (Jan 92)

         1. Using the COMSPEC parameter to establish the default value
            of the COMMAND.COM path
         2. Adapting window procedures to a wider range of graphic
            controllers

            CHANGES TO VERSION 5.7 (Mar 92)

         1. Removing anti-piracy protections (e.g. passwords)

            CHANGES TO VERSION 5.8 (Mar 93)

         1. Adapting SuperMemo 5 for shareware distribution

=======================================================================

             VERSION 6.0 (May 1991)

         1. The whole program was written anew from scratch
         2. New optimization technique based on sketching forgetting curves
            for particular difficulty categories and repetition numbers.
            The whole record of repetitions is stored in the database
         3. Programmable forgetting index used to control the speed
            of learning!!!
	 4. Simplified structure of the database (4 instead of 6 files) with
            the INF file stored in the compressed form (reducing the size by
            80%)
	 5. Fast daily burden with the possibility of editing
            items scheduled for a given day
         6. Monthly and annual burden
	 7. New process parameters:
	     - Average repetition, lapses, interval, factor
	     - Requested and measured forgetting index
	     - Retention approximation
	     - Mean repetition time
	     - Workload
         8. Keyboard shortcuts (Alt, functional keys)
         9. Simplified and economized menu structure
	10. Smoothing of the matrix of optimal intervals by means
            of hill-climbing approximation
	11. Random-hit, real-time smoothing scheme
        12. Extended fault tolerance mechanisms
        13. Protection against using unclosed databases
        14. Extending the Editor by commands such as Paste, Cut, Delete
            Word, Delete-EOL, Copy Block, Move Block, Delete Block,
            Word Right/Left, Replace String, Swap Lines, etc.
        15. Option Find extended by Replace
        16. New file selection option with separate panes for changing
            the drive, path and template
        17. Option Duplicate Item in the browsing mode
        18. Final drill file (*.REP) not deleted upon closing the database
            (unless empty)
	19. New, context-sensitive, 180-page help
	20. UK/US date format as a parameter
	21. Option for changing all directory paths
        22. Option for turning the color on and off
	23. Single stage compression. No regular garbage-collection
	    required
	24. Extension of Optimal factor and Optimal interval option
            for factors higher than 2.5
        25. Separate option for closing the database in use
        26. Mechanisms for preventing piracy (e.g., passwords, database
            marking, registration number, etc.)
        27. Maximum number of items in a database increased from 10,000
            to 60,000

             CHANGES TO VERSION 6.1 (Jan 1992)

         1. Using the COMSPEC parameter to establish the default value
            of the COMMAND.COM path
         2. Using the SM6.EXE directory as the default parameter
            directory (previously the working/current directory was
            used)
         3. Adapting window procedures to a wider range of graphic
            controllers
         4. Preventing DAT files from having zero size (problems with
            COPY in DOS)
         5. New, 100-page User's Guide including a chapter devoted to
            paper-and-pencil applications of SuperMemo

            CHANGES TO VERSION 6.2 (Mar 1992)

         1. Removing anti-piracy protection mechanisms (e.g. passwords)

            CHANGES TO VERSION 6.3 (Apr 1992)

         1. Option Schedule item in the browsing mode (used to memorize
            selected intact items)

            CHANGES TO VERSION 6.4 (Jun 1992)

         1. Option Mercy on the Miscells menu (used to evenly distribute
            outstanding items in the future schedule in order to minimize
            the damage to memories)
         2. Word-wrapping in the item editor
         3. Faster Find and Delete for large databases
         4. Command interpreters different from COMMAND.COM may be used in
            OS Shell
         5. File selection window can be used to determine the paths to
            (1) help file, (2) command interpreter, and (3) parameter file
         6. Chapter on theoretical aspects of SuperMemo in the User's
            Guide

            CHANGES TO VERSION 6.5 (Oct 1992)

         1. Option Wipe on the Miscells menu (used to reduce the number of
            repetitions by elongating intervals of short-interval items)
         2. Option Reset-Wipe on the Miscells menu (used to reduce the
            number of repetitions by resetting short-interval items)
         3. Text buffer used by option Cut block and Paste block is
            preserved when editing more than one item
         4. Simplified block operations in the item editor (F7 - mark,
            F8 - cut, F9 - copy, F10 - paste)
         5. Reducing the size of the program by compiling it with Turbo
            Pascal 6.0 compiler (previously Turbo Pascal 4.0)

            CHANGES TO VERSION 6.6 (Jan 1993)

         1. Possibility of defining dedicated fonts for databases using
            non-standard characters (EGA/VGA only)
         2. New installation utility
         3. Compiling the program with Borland Pascal 7.0
         4. REPSTR.EXE utility for font and substring conversion


           (SUPER-MEMO 7.0, January 1993, see further)


            CHANGES TO VERSION 6.7 (May 1993)

         1. Possibility of redefining keyboard codes with KBD files
         2. Font Designer shareware included in the package
         3. Allowing full path specification in Toolkit programs instead
            of just a database name

=========================================================================

            SUPER-MEMO 7.0 FOR WINDOWS (Jan 1993)

         1. The whole program was written anew from scratch in Borland
            Pascal for Windows version 7.0
         2. New database file managing options:
              - Delete Database
              - Rename Database
              - Cut Drills (removing items scheduled for Final Drill)
         3. Possibility of using several database editing windows at
            the same time; plus independent Learn, Search and Random
            Test windows with all operations of the editing mode
            available. This allows, for example, to browse, search,
            edit or expand the database during learning
         4. Possibility of using up to 4 independent Append
            windows at the same time (e.g. to add or duplicate items
            at Learn or at Search)
         5. Possibility of transferring items and text blocks between
            all sorts of item windows (via Clipboard)
         6. Possibility of duplicating items in the Append window
         7. Forgetting curves available from all options displaying
            optimization matrices (R-Factors, O-Factors, optimal
            intervals, and Cases)
         8. Possibility of working with a few databases at the same
            time using separate instances of the program
         9. New, 140-page manual with an extended FAQ chapter, and a
            chapter describing the SuperMemo Database Toolkit

            CHANGES TO VERSION 7.1 (May 1993)

         1. Adding Image menu in editing windows (creating up to
            60,000 graphic images associated with items)
         2. Adding Audio menu in editing windows (recording and playing
            up to 60,000 sound files associated with items)
         3. Configuration AutoSave
         4. Remembering location and sizes of working windows in the
            program configuration
         5. Possibility of associating icons with databases in the
            SuperMemo group (database name as a parameter for SM7.EXE)
         6. Adding Advanced English and SuperMemo Toolkit to every SM7
            package (compressing all installation files on two 1.44 MB
            floppy diskettes)
         7. Database name in window captions (for switching with Alt-Tab
            between multiple databases used at the same time with shared
            code of many program instances)
         8. Parameter Future Reps estimating the number of repetitions of
            a given item in the nearest 30 years
         9. Possibility of resuming search with a new substring parameter,
            upon finding an item
        10. Adding the option View Text Files
        11. Providing names for grades (bright, good, pass, fail, bad,
            and null)

            CHANGES TO VERSION 7.2 (Sep 1993)

         1. Possibility of using any of the Windows fonts in any color
            in SuperMemo items (option Font)
         2. SETUP.EXE added to the installation utility to install
            SuperMemo databases and selected SuperMemo components
         3. Adapting the program to run on Windows NT
         4. Adding the Import option on the Image and Audio menus
         5. Adding case insensitive item search
         6. Adding a option for viewing the matrix of retention at
            repetitions for particular E-factors and reptition nos
         7. Adding options Copy and Move database
         8. Adding an option for defining text, sound and graphic
            editors in Options
         9. Adding a configuration file for each database with parameters
            such as desktop, font, color, search string, etc.
        10. Enhancing SuperMemo Toolkit by operations on bitmap and
	    sound files
        11. Option Word-wrapping in the Options dialog
        12. Option Demo on the Miscellaneous menu

            CHANGES TO VERSION 7.3 (Mar 1994)

         1. Adding full-screen item browsers (e.g. for all items,
            for intact items, for memorized items, for outstanding
            items, for intractable items, etc.)
         2. Possibility of searching for all items containing a given
            substring, and reviewing these items in the search
            browser (the search browser sequence is preserved between
            sessions)
         3. Possibility of changing the order of items in the database
            (by means of the general browser)
         4. Possibility of editing the intact queue (by means of the
            intact browser)
         5. Option Item:Transfer in editing windows (used to quickly
            transfer the current item to another database)
         6. Rescue integrated with the program as File:Recover
         7. Introducing the concept of a leech (item which slows down
            the learning process). Possibility of extracting leeches
            using the criteria of E-factor, number of lapses, and
            the interval. Possibility of browsing leeches and randomly
            reviewing leeches.
         8. Possibility of using filter files with TO_TEXT.EXE that
            allow defining (1) items that should be included/excluded
            in/from the output, (2) strings that should be replaced, (3)
            comment that should be cut, (4) ordinal number delimiters,
            (5) definitions of ordinals used in sorting databases, etc.
         9. Possibility of quickly opening one of the 5 recently used
            databases from the pick list on the File menu
        10. Automatically opening the last used database at running
            SuperMemo (second instance opens the last but one database,
            etc.)
        11. Resizable question-and-answer field in editing windows
        12. Implementing the Append window which is orthogonal to Edit
            windows (e.g. to allow adding bitmaps and sounds at Append)
        13. Possibility of fast switching between appending and editing
            modes (e.g. to edit recently appended items)
        14. Possibility of independently passing one of the three stages
            of learning: outstanding, memorizing and final drill
        15. Random test on item subsets: intact items, memorized
            items, intractable items, outstanding items, etc.
        16. Possibility of alternative viewing items scheduled for a
            particular day in the item browser (in Analysis:Burden)
        17. Preserving the intact sequence in Garbage and in Recover
            (and RESCUE.EXE)
        18. Possibility of viewing items scheduled for a particular
            month by clicking entries in the Monthly Burden
        19. Possibility of arbitrarily choosing the first interval when
            memorizing an item
        20. Possibility of installing database True Type fonts with
            SETUP.EXE (TTF files)
        21. True Type support in printing
        22. 256-color bitmap support
        23. Optimized design of menus and accelerators (faster, more
            orthogonal, more Windows-like and more intuitive)

            CHANGES TO VERSION 7.4 (Sep 1994)

         1. Integrated Toolkit (including tools such as: Recover, Reset,
            Transfer, Sort, Export text, Import text, Export SM6,
            Import audiovisual files, Cross-section, SetUp, etc.)
         2. Child browsers (e.g. Child:Search makes it possible to
            selected from the browser all items containing a given
            substring; Child:Leech extracts all difficult items, etc.)
         3. Lexicon and Audio lexicon make it possible to instantly
            access words and audio phrases stored in the database (the
            lexicon may be built for a custom-made database with
            Build Lexicon using user-definded filter file)
         4. Mercy into the future (e.g. in order to pass all repetitions
            scheduled for a vacation period)
         5. Possibility of spelling drills with the Spell-Pad
         6. Fuzzy search (e.g. in order to find 'bureaucracy' without
            remembering the exact spelling)
         7. Multiple user menu that makes it possible to define a number
            of users with separate database directories and database
            password protection
         8. Possibility of using different fonts in questions and in
            answers (e.g. Latin alphabet in questions and Cyrillic in
            answers)
         9. Four modes of accessing audiovisual files (e.g. in order to
            repeat audiovisual items whose bitmaps and sound files come
            from a database stored on CD-ROM, in a colleague's
            directory, etc.). Possibility of editing audiovisual links
            in a database with BMP and WAV files stored on CD-ROM.
        10. Smart Garbage makes it possible to clean the database
            directory from all optional files
        11. Smart Reset makes it possible to selectively reset the
            elements of the learning process (e.g. forgetting index,
            optimization matrices, entire database, etc.)
        12. A synchronous Browser's Edit window in browsers makes it
            easier to browse multiline items, and items illustrated with
            bitmaps
        13. Possibility of defining user's keyboard (by defining KBD
            files that will assign selected character codes to Alt-key
            combinations in the item editor)
        14. Possibility of comparing one's vocal responses with original
            audio records in the database
        15. 3-D graphs with optimization matrices
        16. More accurate approximation of forgetting curves

            CHANGES TO VERSION 7.5 - Programmable SuperMemo (Jan 1995)

         1. Database programmability, i.e. the ability to execute DLL
            database modules (to open the way to using SuperMemo in
            procedural learning, problem solving, playing musical
            instruments, creativity training, etc.)
         2. Adding Touch-typing programmed database to every package
         3. Option Action : Previous in editing windows provides access
            to up to fifty recently reviewed items
         4. Option of selecting individual items in the browser, and
            creating a child browser with selected items
         5. Adding final drill browser
         6. Option Item : Drill in editing windows makes it possible to
            add an item the final drill queue
         7. Option Move : Randomize in the browser makes it possible to
            scramble the browser's content (e.g. to randomly reshuffle the
            final drill queue, etc.)
         8. Options Edit : Replace and Search : Replace all in the
            browser
         9. Option Browser : Reset makes it possible to reset all items
            kept in the browser
        10. Option Browser : Random test makes it possible to run a random
            test on items kept in the browser
        11. Option Item : Kick in random tests makes it possible to eliminate
            items from random test (e.g. by providing passing grades)
        12. Sound importing options in the browser
        13. Output of Tools : Cross-section can be imported to standard
            spreadsheets (e.g. Quattro Pro, Excel, etc.)
        14. Adapting the program to run in Windows 95


=========================================================================

       SUPER-MEMO WORLD
       P.O. Box 1
       Poznan 48
       POLAND
       Tel: (48) 61 764066, 764073, 203157
       Fax: (48) 61 764073, 793435
