Sunday, May 23, 2010

Retro Computing

When I bought my FIRST Home Computer back in 1983, like millions of other users out there it was a Texas Instruments - TI 99/4A. Like many other users out there I learned how to program and use it for technical office processes like word processing (TI Writer) & making and using spreadsheets (Microsoft Multiplan).

Like many a 'first love' that TI 99/4A computer was never completely remembered or wholly forgotten!!

I packed my TI 99/4A away long ago, but recently ran across Cory Burr's Win99/4A, an EXCELLENT simulator of the TI 99/4A with full speech capabilities, sound capabilities, and very good module compatibility that runs on PCs running "Windows". I can now get back into writing programs in Extended Basic, using the Mini Memory Cartridge again, and using the good educational modules for my nieces, nephews, and other children; all this on my PC.

Just go to on the http address below. It will take you directly to where the file is located and can be downloaded.

Over 200 Cartridges (Modules) in file format are available for download for Win994a. Just go to on the http address below. It will take you directly to where the files are located and can be downloaded.

Download and uncompress the cartridge(s) item. This may take a little while since the file is roughly 27meg. Uncompress the contents of this file into the "carts" directory under the "Win994a" folder of your hard disk. This will make all 200+ carts available to Win994a next time you start it up. Enjoy.

Try it!


Win994a-TI-99/4A Simulator for Windows

Win994a is a TI-99/4A simulator written by Cory Burr that installs and runs in the Windows environment.

Win994a is not a perfectly accurate emulation of the TI-99/4a; and it was never intended to be. The author decided not to implement certain aspects of the TI-99/4a either because they are rarely used or were considered of "no-value-added". The author vigorously apologizes to those users who will miss a favorite peripheral or item of functionality. The list below details the various functionality provided by the Win994a Simulator.

General Functionality:

Boots and runs all console ROM and GROM based functions including console BASIC.
CRU bits for the keyboard are implemented; some CRU bits for the Disk Controller and RS232 Interface are implemented.
TMS9918a video chip functionality is implemented.
TMS9919 sound chip functionality is implemented.
TMS5520 speech synthesizer chip is implemented.
Full floppy disk and disk controller functionality.
Full cassette tape functionality for CS1.
32k Memory Expansion supported.
PIO and RS232 ports are supported, but using a different method than the original TI99/4a.
Support for one joystick input (using numeric keypad).
Runs over 200 cartridges correctly. Cartridges that depend on non-implemented CRU bits or non-documented video chip operation will fail.


All TMS9940 CPU instructions are implemented. CPU clock ticks are accumulated for both instructions and fast/slow memory accesses. When enough clock ticks have been accumulated for 1/16 of a second real elapsed time, Win994a checks the high precision clock (available in the PentiumPro and above processors) and gives up enough of the time slice so that accurate running time is maintained.

Console based cassette tape functions for CS1 supported.
Console ROM and multiple console GROM functionality implemented.
Multiple peripheral based ROMs supported.
Multiple cartridge based ROMs, GROMs, and RAM supported.
TMS9918a: Uses DirectX for all operations. Video modes GRAPHICS, TEXT, MULTICOLOR, BITMAP, BITMAP-TEXT, and BITMAP-MULTICOLOR are implemented. Sprites, sprite coincidence, screen blanking, and vertical interrupt operations are implemented.
TMS9919: Uses DirectSound for all operations. All three voices and noise channel supported.
TMS5520: Speech synthesizer functions implemented.
Disk Controller and three floppy drives fully supported.
PIO and RS232 ports are supported, but using a different method than the original TI99/4a. PIO/1, PIO/2, RS232/1, RS232/2, RS232/3, and RS232/4 provide six separate pathways for making printouts through Window's print system. They do not provide input/output capabilities with the PC's actual hardware ports.
Support for one joystick input (using the keyboard numeric keypad) is implemented.


Using RXB [Rich Extended Basic] and FUNLWEB [Funnel Web] together is as close as one can get to having a "DOS" like operating system for the TI99/4A Computer along with its Emulators & Simulators*. No longer having a physical TI99/4A computer set up, one can imagine this must be the same situation for those users that have the ability to use this physical set up of their computer.

Again this example just shows anyone that is willing to investigate how the potential of this computer was not developed by its parent company in a corporate decision to not have this consumer computer compete with its business computer.

RXB was developed by Richard Gilbertson and FUNLWEB was developed by Tony & Will McGovern, these two groups of gentlemen were thousands of miles apart and probably developed their programs out of a necessity because the 'operating system' that was offered by the parent computer company was so inferior. Sometimes the small group can really out perform the big company.

Now maybe the TI99/4A Computer along with its Emulators & Simulators* users with the RXB & FUNLWEB programs could start a mild rediscovery of this computer type if they each made a concerted effort to publicize the availability of this material worldwide over the Internet


*Classic99, M.E.S.S., PC99, and Win994a