In 1991, SuperMemo 6.0 for DOS was released. It was written from scratch in Turbo Pascal 6. Apart from introducing major changes to the repetition spacing algorithm, it was the first SuperMemo designed with a view to commercial distribution. It was also the first commercial SuperMemo that has sold over 10,000 copies. The idea of plotting forgetting curves for all optimal factors has added greatly to the theoretical validity of the SuperMemo algorithm that could now be verifiably shown to produce the optimum repetition spacing for a given level of knowledge retention. Future improvements to the algorithm could therefore only accelerate the convergence of the starting memory model to the optimum model. SuperMemo 6, as the finalist of Software for Europe Competition 1992, has brought SuperMemo to public attention allowing it to break the image of an intricate software product for a hermetic group of technically-minded people. Instead SuperMemo 6 became one of the best-selling pieces of software in Poland in the early 1990s. In January 1995, SuperMemo 6 entered public domain and is since available from multiple shareware sites and shareware CD-ROMs around the world. Even with the advent of SuperMemo 8 in 1997, many users remained faithful to the old good DOS version
Major new features introduced to SuperMemo 6 for DOS (1991-1993):
- New optimization technique based on sketching forgetting curves for particular difficulty categories and repetition numbers
- User-defined forgetting index can be used to control the speed of learning
- Repetition calendar with the possibility of editing items scheduled for a given day
- Monthly and annual repetition calendars
- New process parameters: Average repetition, Average lapses, Average interval, Average E-factor, Requested and measured forgetting index, Retention, Mean repetition time, Workload, etc.
- Extending the item 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.
- Option Find extended by Replace
- Option Duplicate Item in the browsing mode
- Maximum number of items in a database increased from 10,000 to 60,000
- Option Schedule item in the browsing mode (used to memorize selected intact items)
- Option Mercy used to evenly distribute outstanding items (e.g. after a vacation break)
- Option Wipe is used to reduce the number of repetitions by elongating intervals of short-interval items (replaced with multicriterial Mercy in SuperMemo 8)
- Option Reset-Wipe is used to reduce the number of repetitions by resetting short-interval items (replaced with multicriterial Mercy in SuperMemo 8)
- REPSTR.EXE utility for font and substring conversion
- Possibility of redefining keyboard codes with KBD files
- Font Designer freeware included in the package
Major releases:
- SuperMemo 6.0 (May 1991)
- SuperMemo 6.1 (January 1992) - adapted to a wider range of graphic controllers
- SuperMemo 6.2 (March 1992) - removing copy protection
- SuperMemo 6.3 (April 1992) - option Memorize added in the browsing mode
- SuperMemo 6.4 (June 1992) - option Mercy for rescheduling repetitions
- SuperMemo 6.5 (October 1992) - option Wipe for resetting short-interval items (this option was abused heavily and was not transferred to the Windows version)
- SuperMemo 6.6 (January 1993) - recompiled with Borland Pascal 7.0
- SuperMemo 6.7 (May 1993) - customizable keyboard codes, Font Designer freeware
- SuperMemo 6.7 PD (January 1995) - released to Public Domain (see: http://www.simtel.net/pub/dl/45054.html)
If you would like to download SuperMemo freeware see here
Important! SuperMemo 6 may no longer work correctly in MS DOS Prompt on newer Windows platforms (esp. the NT line). You can still use it in DOS. If you prefer Windows, you can upgrade to Windows freeware
