From Ninerpedia
Revision as of 23:44, 12 November 2012 by Mizapf (talk | contribs)
Jump to navigation Jump to search

An emulator is a program that simulates the components of the real machine as precisely as possible. It contains lots of simulations for the various chips like the processor, the video chip, the sound chip, ROM, RAM, and so on. By connecting all simulated circuits according to the schematics of the real machine, the complete system shows a behaviour that simulates the behaviour of the real machine.

In contrast, a simulator is a program that is designed to function like the original target regardless of how it is implemented underneath the covers of the program. The goal is to provide an application to the user which looks and feels like the real machine it is intended to simulate.

Emulators have to execute the ROM contents of the real machine, so they need dumps from its ROM memories. Simulators can use their own implementations of parts or all of the system behaviour. A simulator is great for running programs that were designed for the system. A simulator is not good for developing low-level applications on since it does fully implement the underlying hardware.

While emulators - if done correctly - are a very precise mapping of the real machine, users may experience a more comfortable handling with simulators. For instance, simulators may provide an access to the host file system and allow the simulated system to load and store files on it. In contrast, emulators usually make use of image files to represent the data medium (like a floppy disk) and make the ROM "believe" it sees the real medium. This requires all operations to be done on images which are usually only readable within the emulator - you cannot use PC tools to edit files. Also, it is difficult to integrate enhancements beyond the features of the real machine.

Win994A is a simulator, while MESS is an emulator. Classic 99 shows characteristics of both.

What emulators exist for the TI-99/4a?

Fortunately there is a variety of emulator that you can use. While most are free, one in particular is commercial and requires payment. Here is a brief summary of the emulators:

  • Classic99 - (Add more Information Here)
  • MESS - stands for "Multiple Emulator Super System" and not only does it emulate the TI-99/4a, it does a whole host of other systems. This a great tool for those that work with multiple types of computers and systems. The focus of MESS is a precise emulation, sometimes at the cost of usage comfort.
  • PC99 - it runs in the DOS enviorment and emulates the TI-99/4A and some peripherals. Owners of PC99 can purchase the CyC CD which has all the modules and disks for the TI in PC99 format. Comes with manuals and other materials. Link: CaDD Electronics Home Page
  • TI4Amiga - (Add Information Here)
  • TI-99/Sim - (Add Information Here) Link: http://www.mrousseau.org/programs/ti99sim/
  • TI994W - Link: http://members.ziggo.nl/fgkaal/Software/sw_ti994w.html#ti994w (Add Information Here)
  • V9T9 - is another popular emulator. Though the author is no longer actively developing the software, it provides a great emulator for the TI. A lot of modules and disks exist in V9T9 format as well. Also available as MacV9T9 - (Add Information Here).
  • Win99/4A - in some regards can be considered a simulator rather than an emulator. The author acknowledges that they excluded features that are not useful or appear to be rarely used. That said, it is great product and currently is under active development.

What is the easiest emulator to start out with?

I'm fairly new to the emulation scene for the TI and have a pretty good idea of how I would rank them as far as being easy to setup and use.

  • Win994a - single installation program for the entire suite. Hands down the easiest to get running.
  • MESS - Finding the ROMs is the tough part but I created a bundle for people to use so that problem is solved. Easy to unzip and setup.
  • PC99 - Great instructions and easy to setup. The only reason that it is 3rd is that it costs money so MESS beat it out.

What TI emulators exist for Macintosh systems?

MacV9T9 is sole native TI emulator for the Mac. It is no longer being maintained and it supports the 040 and PPC architectures and requires a pre OS X environment to run. NOTE: There is an open-source utility called SheepShaver that allows you to run PowerPC - Classic MacOS applications and this could be used to run MacV9T9. MESS is also available for the Mac (older and newer) and the TI-99/4, TI-99/4a and TI-99/8 systems are emulated in this environment. Beyond that the only option is run Windows/DOS based emulators within a virtualized environment.

Here is a short list of the possible VM environments for the Mac:

  • Virtual PC for Macintosh - does not support Intel Macs and will not be updated (damn that Bill guy!)
  • Parallels - only supports Intel based Macs
  • VMware Fusion - only supports Intel based Macs
  • Apple's BootCamp - only support Intel Based Macs and requires at least Leopard
  • DOSBox - for both PPC and Intel Macs running OS X

Which emulator would you use and for what reason?

As you can tell by the categories on this FAQ, there is a focus on Win994a, MESS and PC99. Each of them have their pros and cons so hopefully this entry helps steer you in the right direction.

If you are looking to run existing software and generally to play/use the TI-99/4a I would look at either Win994a or MESS. Win994a is a great all-in-one suite that is easy to get up and running and it contains a large library of software. The only problem with Win994a is the "Win" part. If you use Linux, Unix or a Mac then this does you no good. At this point MESS would be a better choice.

If you are looking to play around with the TI and other systems (Apple, Commodore, etc.) then MESS is definitely your best option. MESS allows you to emulate A LOT of different systems. And as previously mentioned, it runs on a variety of platforms.

If you are look to play around with the TI and are looking to develop I would point you toward PC99 and or MESS. Both of these titles are focused on emulating the underlying hardware and that helps out no matter what level of programming you are doing (code, DSR, etc). I'm not saying development can't be done with the other emulators, I'm just pointing out which one is better suited.

Summary: Windows users looking to play -> Win994a, MESS Non-windows user looking to play -> MESS Windows users looking to develop -> PC99, MESS Non-windows users looking to develop -> MESS

Which emulators use which types of disk images?

This is quick list but it should be sufficient and it covers the most popular emulator:

  • V9T9 - v9t9 (.dsk)
  • MESS - v9t9 (.dsk)
  • PC99 - pc99 (.dsk)
  • Win994a - v9t9 (.TIDisk)

Is there a way to capture and use cassette tape data with emulators?

Yes. There is a program out there called CS1er that will take a WAV audio file of a TI Cassette Program and convert it to a FIAD file. FIAD is the native V9T9 file format and many emulators support V9T9 formats. You can find more about CS1er at the following website: http://www.cs1er.com

How do I convert PC99 format images to V9T9 format?

The easiest method, because it is GUI driven, seems to be to use Fred Kaal's TiDir program. Here are the basic steps:

  1. Open TiDir to the directory where you PC99 image file resides.
  2. In TiDir select your PC99 image.
  3. From the file menu choose "Convert PC99 DSK-file to TI99 DSK-file"
  4. TiDir will prompt you for a location and file name to save the file.

There also is a command prompt utility on WHTECH but this one seems a bit more straight forward and it provides other great functionality! TiDir and other programs can be found on Fred's site which is index on my Links page at: http://www.ti-994a.com/links.html

Thanks to Jacques Groslouis for pointing out that TiDir has this functionality.

What is a "TIFILES" file?

See the section on TIFILE format.

If you were to take a file and send it over to a PC or some other computer via a modem or serial cable it would arrive on the other end but lose some information. It would lose information like what kind of file it is, protection status, how large it is, etc. In order not to lose that information, proper communication programs on the TI prepend (stick on the front) a 128 byte header to the file that captures this information. So now when the file arrives on the other computer it is actaully a little bit larger.

When the 128 byte header is prepended to the file it becomes a "TIFILES". So by definition, a TIFILES file is a regular file with a 128 byte header. Now if you were to send that same program back to the TI, the 128 byte header gets read so the file is created properly on the TI. Of course, the 128 byte header is removed when it is back on the TI. The 128 byte header is small set of information used to properly rebuild the file once sent back to the TI. If you send a NON-TIFILES file (one without the 128 byte header) to the TI it will get built but more than likely it won't work properly.

Is it possible to load an IDE drive on a PC with information from disk images (V9T9, PC99) and then move it to the TI with an IDE controller for use?

I don't believe a tool or program exists to do this. This is speculation here but in order to do this one of the following must ocurr:

  1. There must be a program written on the PC that understands PC99/V9T9 images and a driver that supports the TI formatted version of an IDE drive (essentially a PC equivalent of the DSR).
  2. One of the emulators must be aware and be able to use a TI formated version of an IDE drive which would still require a driver to be written.

So from those two possibilities the need for a driver (DSR like program) for the PC to understand and to be able to work with a TI formated IDE is requried. Also, the driver would have to either work with an TI IDE system based on Thierry's DSR and/or Fred Kaal's DSR. All in all this is a big effort.

Original question by: Alfredo Cevolini


For all information on Win994a please see the dedicated Win994a section.


For all information on MESS please see the dedicated MESS section.


For all information on PC99 please see the dedicated PC99 section.

How do I move a file from my PC to a emulator images file?

This is a broad question so let me put some parameters around it. Let's assume that someone is is looking to move a TI type file (text, basic, archive, etc.) to either a v9t9 or pc99 image. PC99 uses the pc99 image, Win994a and Mess use the v9t9 image type file.

Let me state that there are lots of ways to do this. I could use a serial connection with PC99 or some other craft utility. For simplicity sake I'm going to describe to methods that are easy to use and that anyone with a PC can use.

Win994a DiskManager

This tool that comes with Win994a is a great utility. You can create a virtual floppy (v9t9 image) or use an existing image. Make sure that you select the image you want to use by clicking on the Browse button in the upper right corner.

With your image selected you can now click on the "Import FIAD File" which will move the file(s) you want to the disk image. IMPORTANT: in the Files Type field change the value to "All Files (*.*)". You can now browse to files you want to import, select them. That's it!


This is a utility that can do a lot with real TI Disks and virtual disks. The first thing to understand is that there is now a 3rd image format for this program that is called a "TI99-PC Image".

You will want to do this if you want to move a file to PC99 or if you don't use Win994a. The process is as follows: Import your files to a TI99-PC Image and then import that image to either a PC99 or v9t9 image. Yes it is extra steps but it works.

You can find TI99-PC in the PC Utilities folder on WHTECH. There is a manual to explain all of the details. I'm just going to give you the menu choices here:

1) To import a file from DOS to a TI99-PC image you will choose, from the Main Menu, option #2 and then option #6.

2a) To import a TI99-PC Image file to a PC99 image you will choose, from the Main Menu, option #1 and then option #3.

2b) To import a TI99-PC Image file to a v9t9 image you will choose, from the Main Menu, option #1 and then option #5.

NOTE: Greg McGill had the suggestion of using TI99-PC so credits to him on that!

Can I bring my BASIC programs over to my PC as a text file for viewing?

Yes. Fred Kaal has a great program called TiDir that allows you to view/extract the contents of emulator files and disks. TiDir works with both V9T9 and PC99 format files/disks. Both MESS and Win994a use V9T9 format and PC99 uses PC99 format. The program even allows you to work with ARK files created by Barry Boone's Archiver. A link to Fred's site can be found on http://www.ti-994a.com/links.html.

Win994a Users: there is a built-in way for Win994a to have output sent to a printer connected to your Windows PC. Another entry in the FAQ explains this in detail and it can be found under: Emulation -> Win994a

MESS Users: there is also a built in way for MESS to print to a text file and then on your PC you can do what you want with it (save it, print it, etc). Another entry in the FAQ explains this in detail and can be found under: Emulation -> MESS

What is the Cyc CD-ROM?

The "Cyc", as it is known, is a great collection of software and documentation that is meant to complement PC99. Since the the software is arranged for PC99, the owners of this commercial CD will only sell it to registered owners of PC99. The Cyc contains the following:

  • All TI PHM Modules in PC99 format.
  • All released TI PHD Diskettes in PC99 format.
  • All TI PHM and PHD Manuals in PDF format.
  • Articles by noted TI authors in PDF format.
  • Full text of certain TI books in PDF format.
  • A listing of all books related to the TI.
  • An alphabetical List of 1,500 pages of TI information in PDF format.
  • PHx lists that shows all TI numbered products (PHM modules, PHD disks, PHT cassettes) in PDF format.
  • Many third-party and unreleased TI modules in PC99 format.
  • Indexes to all major TI publications, and full text of selected magazines in PDF format.
  • User group disk and publication collections in PDF and PC99 format.
  • Information, manuals, and disks from TI vendors in PDF and PC99 format.
  • Thousands of other disks in PC99 format.

More information about the Cyc and PC99 can be found at: http://www.cadd99.com/

Further links

pc99 - http://www.cadd99.com/

v9t9 - http://www.99er.net/emul.shtml#V9T9

mess - http://www.mess.org/

win994a - http://99er.net/win994a.shtml