In slower times, 34 years ago, a desperate plea was posted to a photographer's BBS in Los Angeles: “Help! I just replaced my 4.77MHz IBM PC with a 25MHz '386 computer and my favorite pinball game is now unplayable!” Dr.David responded to that plea and the rest is history…

Version history – Mo'Slo 4BIZ

Save your download instructions! You can download again and re-install when an update to your major version is released.

30 December 2006 – This update corrects a bug in the Slo'Win EZ program that caused the SParam speed setting to revert to the default slowdown speed. Slo'Win EZ has been updated from version 3.3 to 3.3.2. The Mo'Slo 4BIZ program is unchanged.

5 August 2006 – Version 3.3.2 eliminates a command line parsing error that can preclude the use of Keyboard control and Quickload, and can cause the Windows 9x/ME method 2W speed test to fail. This error was introduced in version 3.3.1.

11 May 2006 – Version 3.3.1 eliminates a restriction that disallowed installation in paths with long filenames. Mo'Slo 4BIZ can now be installed in any path recognized by Windows.

19 March 2004 – Version 3.3 adds: (1) the option to execute slowdown and slowed program on a specific logical processor or to execute each on any logical processor on multi-processor and hyperthreaded systems; (2) a system-specific slowdown speed switch (SParam) that bypasses the system test.

5 January 2004 – Version 3.2 adds: (1) Keyboard toggling of slowdown on/off in Windows slowdown methods as well as DOS methods; (2) execution limited to first processor on multiprocessor systems; (3) Mo'Slo 4BIZ-XP window self-minimizes when a slowed program is loaded.

28 August 2003 – Version 3.1 adds: (1) Slo'Win EZ graphical Windows program that allows interactive testing of slowdown parameters and creation of Windows shortcuts in the Program menu and on the Desktop; (2) two new slowdown methods for Windows NT, 2000, and XP, plus a Windows-based slowdown method for Windows 98 and ME; (3) quick abort of system test by left-clicking the progress bar or pressing the Esc key; (4) percent-of-normal slowdown in 0.01% increments; (5) minimize button and slowdown toggle ON/OFF to Mo'Slo window; (6) drag'n'drop repositionable window; (7) improvements to smoothness of Windows slowdown methods and speed of system test.

15 November 2002 – Version 3.0 adds a Windows-based slowdown method for more consistent slowdown on faster systems running Windows NT, 2000 and XP. This is the first major version upgrade to Mo'Slo 4BIZ. Version 2 was skipped to avoid confusion with Mo'Slo Deluxe.

21 June 2001 – Version 1.2 improves accuracy of speed test, especially on AMD processors.

10 March 1999 – Version 1.1 adds slowdown duration option and improves error reporting.

22 October 1998 – Mo'Slo 4BIZ (Mo'Slo for business) is developed to allow easy installation on multiple computers running a specific ‘problem’ application. The default emulation speed of 166MHz is ideal for most business software problems, and when not it is simple to find a system-independent speed number that eliminates system-specific testing. In the course of development, other features are added - such as a significantly-smoother second slowdown method able to slow Windows programs in Windows 95, 98 and ME; and delayed slowdown to allow fast loading of extremely-slowed programs.

Version history – Mo'Slo Deluxe

Save your download instructions! You can download again and re-install when an update to your major version is released.

6 Dec 2007 – Version 3.3 adds the option to disable the COM port FIFO buffer as required by some Motorola RSS and machine control software.

17 Feb 2007 – Version 3.2.1 uses a larger program stack for compatibility with FreeDOS. (FreeDOS is a free MS-DOS substitute that—when reducing memory allocation—uses significantly more of a program's stack than MS-DOS does.)

26 May 2006 – Version 3.2 adds the option to be installed as a terminate-and-stay-resident (TSR) program.

22 September 2005 – Version 3.1.1 improves keyboard control. Control is maintained even when a slowed program changes the keyboard interrupt vector.

8 September 2005 – Version 3.1 adds a third slowdown method that uses the ultra-fine APIC timer on newer systems. As with method 2, method 3 can reduce power consumption (and heat) when used in real-mode MS-DOS.

7 August 2005 – Version 3.0 is a very major upgrade, adding a second, smoother slowdown method that can actually reduce power consumption, cache disabling, a 0.01% slowdown increment, 5 processor emulations, a switch to slow a command processor, and a simplified keyboard speed control. All this in a reduced memory footprint!

29 February 2000 – Version 2.2 now uses 32-bit registers for timing. This allows support for processors faster than 1 THz. Mo'Slo Deluxe no longer runs on processors prior to the Intel 80386 (but…who cares?).

13 July 1997 – Version 2.1 adds keyboard control of slowdown and support for faster processors.

13 February 1996 – Version 2.0 is the first release of Mo'Slo Deluxe—the commercial version of the basic Mo'Slo. Enhancements to the basic Mo'Slo include the ability to slow batch files, pass parameters to slowed programs, and specify percent-of-normal-speed in 0.1% increments.

Version history – Mo'Slo basic

Once licensed, Mo'Slo basic can be upgraded within a major version by simply downloading and installing the most recent evaluation version over the old. The license remains valid and the nag screen does not appear.

17 Feb 2007 – Version 1.5.1 uses a larger program stack for compatibility with FreeDOS. (FreeDOS is a free MS-DOS substitute that—when reducing memory allocation—uses significantly more of a program's stack than MS-DOS does.)

7 August 2005 – Version 1.5 has been rebuilt around the same slowdown engine developed for Mo'Slo Deluxe version 3. This adds a 0.01% slowdown increment and a second, smoother slowdown method that actually reduces power consumption in real MS-DOS. Compatibility with a wide range of programs is improved, and the second slowdown method is able to slow many programs in Windows NT/2000/XP.

20 April 2004 – Version 1.4 now uses 32-bit registers, restricting use to processors 80386 and later but increasing compatible processor frequencies to above 1THz (1,000,000 MHz) and improving smoothness. Mouse monitoring - which limited slowdown amount in some games - is removed.

30 December 1997 – Version 1.32 adds mouse and HDD monitoring to avoid startup problems with certain games.

23 September 1997 – Version 1.31 addresses compatibility issues with evolving hardware.

17 October 1995 – Version 1.3 enhances compatibility with faster Pentium computers and reduces memory footprint.

30 January 1993 – Version 1.2 improves the accuracy of the PC-XT emulation speed, and displays the % of normal speed to make it easier to adjust.

10 May 1990 – Version 1.1 is the first Mo'Slo to go into public distribution.

The original Mo'Slo was written in response to a posting on a Los Angeles photographer's private dial-up bulletin board. The poster complained that her favorite pinball game ran way too fast on her new 80386 computer. Dr.David, being an assembly-language programmer with knowledge of PC hardware, wrote a slowdown program that slowed the execution of a specified program to a specified percent-of-normal-speed. After some testing and tweaking, Mo'Slo was posted to the download area of the BBS. It was a big hit, and soon appeared on Compuserve and the IBM support BBS and thence to support sites and forums throughout the rapidly-growing Internet.

This page is a work-in-progress.

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