TI-99/Sim v0.15.0 is released. This is the latest incarnation of an emulator for the TI-99/4A. At first it was a simple text-based simulation of the TI (ti99sim-console) running under MS-DOS™. Then it was ported to OS/2 and graphics support for the OS/2 Presentation Manager was added. Later, it was ported to Windows and had sound support added. Now it's been ported to Linux and Mac OS X and more features are still being added.

TI-99/Sim Features:
General
* Emulation of the TI-99/4A Home Computer.
* Core emulator written in C for portability to multiple platforms.
* Tracks the emulated CPU speed so it runs at the right speed even on the fastest processors.
* Runs under Linux, Mac OS X, and Win32 (Windows 9X, Windows NT)
* Speed is kept as close as possible to the actual speed of the TI.
* Supports banked cartridges (like TI Extended BASIC).
* 32K RAM Expansion emulation.
* Save/restore the complete computer state (So you can pick up that game you were playing right where you left off).
* Save/restore the contents of battery-backed RAM cartridges (Mini-Memory, Gram Kracker™, etc…) to disk when cartridge is removed.
* Support for Gram Kracker™ emulation (requires actual GK GROM images).
* TMS9901 emulation support.
Graphics
* Uses SDL for graphics, sound, and joysticks - supports X11 and Win32.
* All documented modes emulated.
* Full sprite support: 4 sprite per line limit / co-incidence checking / 5th sprite flag/index.
* Scalable & Resizable window.
* Full screen mode.
Sound Support
* Three voice support using native sound device.
* Noise generation supported.
Speech Synthesis
* Access the built-in speech ROM (TI Extended BASIC). NOTE: Requires a speech synthesizer ROM dump.
* Modules with external speech samples (Parsec, Alpiner, Terminal Emulator II, ...).
Joystick Support
* Hardware joystick support.
* Emulated joystick using the numeric keypad.
Disk Support
* Emulation of the floppy disk controller (currently limited to SSSD and DSSD images).
* Complete read/write support for floppy disks. NOTE: Requires a TI disk controller ROM dump.
* Supports disk images created by AnaDisk, v9t9, PC99, and CF7+.
* The disk utility can convert between formats, add, remove, and extract files.

Download: TI-99/Sim v0.15.0
Source:Here