| TOSBOX documentation |
Copyright © 1997-2000 by:
Mark Slagell
3716 Ross Road
Ames IA 50014
USA
Contents
** What it is **
Tosbox provides an environment for running TOS and GEM applications under DOS, Windows (3.1, 95, 98), or Linux (running dosemu). It uses an operating system image which you can create on your actual Atari machine, and operates with most of the PC's peripherals.
The design of Tosbox is unique in working from the system down rather than from the hardware up. The goal was not to make a PC behave as exactly as possible like an ST, but to run Atari applications as smoothly as possible on a PC. Whenever possible, system calls were redirected and translated to their MS-DOS equivalents; then, only in cases where that failed to be reliable, the behavior of the actual hardware was emulated.
As the above implies, Tosbox is not a complete hardware-level emulation of an Atari ST. To run games and graphics demos, I suggest you try PaCifiST, by Frederic Gidouin.
** Requirements **
You need at least ordinary VGA graphics (though SVGA compliant with VESA 1.2 or higher is recommended), a mouse (and mouse driver if running under plain MS-DOS), at least 4 megs of memory, and a hard drive. Because Tosbox runs in 32-bit protected mode, you also need a '386 or newer processor. Finally, you need a TOS image file derived from your Atari computer. ROMIMAGE.TOS, included in this archive, will make that for you.
Supported TOS versions include 1.00, 1.04, 2.05 and 2.06. According to user feedback, TOS 1.02, 1.06, 1.62 and an enhanced 2.06 called "SUPERTOS" are all supposed to work. "KAOSTOS" is apparently too heavily modified for Tosbox to recognize it.
You may find that you need to install a separate DOS-mode VESA driver for your video card in order to use some graphic modes. A suitable driver should have been included on the disk or CD that came with your video hardware.
** Summary of changes in this version **
** Shareware and distribution rules **
As of version 1.10 Tosbox may be registered by simply contacting the author at [email protected] and requesting a key. Those who still wish to contribute money may do so, using the mailing address at the top of this document.
Permission is hereby granted to copy and distribute Tosbox through non-commercial channels, as long as the original ZIPped archive is provided without modification.
ROMIMAGE.TOS) on your Atari computer.CONFIG.BAT, which lets you make configuration choices and test them in the emulator.TB.EXE.Notes:
TB.INI. To use a different configuration, supply its filename as a command line argument to CONFIG (or to Tosbox).** Recommendations **
The higher the screen mode you select, the more horsepower your machine needs. Not only is the VDI working harder, but the emulator has to throw around a lot more data between ST memory space and the PC's video memory. A 486/66 is enough for the ST-compatible modes, but you need something considerably faster if you want to run in 1024x768x16 without spending a lot of time waiting around for redraws. You might find you need to use TOS 2.05 or 2.06 to make the 800x600 and higher modes run properly.
As with an ST, a graphics accelerator is in some cases desirable. The most popular accelerators (NVDI, Warp 9, Turbo ST) are reported to be compatible with Tosbox, though Turbo ST is only effective in the ST video modes. NVDI users report varying success; generally speaking, later versions of NVDI are more compatible with the custom video modes, and 16-color modes tend to be more stable than 4-color modes.
On the other hand, PCs have become so fast that in many cases now, the graphics speedup provided by NVDI and others may be outweighed by the improved overall compatibility that is achieved without them.
Use an alternate desktop, especially if you use the custom screen modes. If you don't have Neodesk, get Thing, Teradesk, or Ease.
Make SERIALFX or HSMODEM a permanent fixture in your AUTO folder. This is important because the serial interrupt code built into TOS has always had buggy flow control, and most PCs have relatively fast modems.
TECHNICAL NOTES
Contents
** Video **
Standard ST modes are provided for the sake of compatibility, and are implemented as standard VGA video on your PC. 640x400 and up requires TOS 1.04 or higher (2.06 recommended), and 800x600 and higher require compliance with VESA 1.2 or higher. If you request a mode that for some reason cannot work with your PC or your TOS version, a lower-resolution mode with the same number of colors will automatically be selected.
It is important to recognize that even if your video hardware is VESA-compatible, you may have to install a DOS-mode driver before the VESA modes can be used. If you generally only use Windows programs, you may have never had a reason to think about this before. So if the custom video modes don't work (or if you always get a lower-resolution mode than you asked for), consult the documentation for your video hardware, or browse the directories of the disk or CD that came with it, or see if the manufacturer has a webpage from which a DOS driver can be downloaded; most manufacturers do.
Vertical blanking is implemented, but horizontal blanking is not. The display is refreshed at a variable rate, more frequently when keyboard or mouse activity has been recently detected, less frequently otherwise to optimize CPU emulation. (This feature can be disabled, giving constant screen refreshes with a slight speed penalty.) Refresh rates are automatically adjusted somewhat according to screen size.
** Blitter **
Blitter emulation is most useful in situations where there is no graphics accelerator in place. On average it is faster to use the blitter than not, but it is still not quite as fast as the real thing in hardware; it cannot, on its own, compete with a good software accelerator like NVDI.
Known problems with the current blitter emulation:
If you don't want to use the blitter, I recommend disabling it in the Tosbox configuration because this is more reliable than turning it off from the desktop. The speed of a modern PC is such that you probably don't need the blitter anyway.
** CPU **
Almost all opcodes are emulated. A few instructions that I have not seen used in any ST programs will produce an "undefined opcode" message if they are encountered; please notify me if this happens.
Most bus errors and privilege violations are detected, but odd address errors are not. Other known quirks:
RTE.** Memory **
It is possible to have up to 14 megs of ST memory.
Depending on your DPMI host, Tosbox might use virtual memory if there is not enough RAM to satisfy the request. This feature is a mixed blessing; if the boot process takes too long, or programs slow to a crawl while the hard drive keeps spinning, try reducing the memory request. If too much RAM is requested and your DPMI host doesn't provide virtual memory, a smaller amount will automatically be allocated.
** GEMDOS **
Disk drive emulation is done entirely at the GEMDOS level. All PC drives can be used, including CD-ROMs and high density floppies.
Swapping of A: and B: on single-floppy systems is handled by the host PC, which instead of giving you the familiar alert box, displays an "insert disk and press key" message superimposed over the ST screen. Press alt-end to clean that off afterwards if necessary. There should be little need for drive swapping on a modern machine with a hard drive, but some older applications may insist on doing it anyway. Swapping is disabled if drive B: is not mapped in your configuration.
Mounted directories allow you to protect data from the emulator. For instance, you may want to hide the root directory of your PC's boot drive (typically by mounting C: as <cwd> during configuration) if you're worried about your five-year-old kid dragging a drive icon to the trash.
Filenames that are legal under TOS but cause errors under MS-DOS are modified in a simple way: all illegal characters are mapped into the 128-255 range by setting the high bit.
Files and folders are manipulated in customary ways. Directories may be read using Fsfirst/Fsnext, but not from the file allocation tables themselves. A few low-level disk functions (Floprw, Flopwr, Flopfmt, Flopvfy, Rwabs) are incompatible or unsafe to use with mounted directories and therefore just return error codes.
I have seen one CPX module that tries to determine drive space using Getbpb() instead of Dfree(), so Getbpb() is partially supported, not enough to supply all the correct information, but enough to keep that CPX from crashing.
The redirection functions Fforce() and Fdup() are implemented only with respect to Fread() and Fwrite(). Redirection has not yet been implemented for Cconout() and similar functions.
The following characteristics of GEMDOS differ from MS-DOS but have been faithfully emulated:
FOOBAR.ABC.DEF and FOOBAR.ABC refer to the same file (GFA BASIC 3.x relies on this quirk).** Floppy support **
It is possible to retrieve data from old ST-formatted floppy disks. To use this feature, you must first have configured Tosbox (either using TBSETUP.EXE or hand-editing TB.INI) with some drive letter specified for floppy mounting; below we will assume that letter is H.
To read an ST-formatted floppy, first pause emulation, then press the F key. The contents of the disk in PC drive A: are loaded into what appears within emulation as a new read-only drive H:, with the original directory structure and file time/date stamps intact. From there the data can be copied to any other location, including a PC-formatted floppy if desired. You will not be able to read copy-protected or corrupted disks, but you should have no trouble with most nonstandard extended formats employing extra sectors and tracks.
** Desktop **
Resolution changes are only supported when you start up in one of the standard ST screen modes. In the custom color modes, trying to switch resolutions from the desktop will confuse the AES, but you can usually switch back easily enough.
In general, the 4-color modes do not work as well as the 16-color and 2-color (mono) modes. I am not sure of the reason for this.
One unusual -- if not necessarily useful -- feature of Tosbox is that you can launch not only Atari programs but DOS programs as well, provided you inform your desktop program that EXE, COM and BAT are executable filetypes. This requires hand-editing DESKTOP.INF or NEWDESK.INF if you're using the built-in Atari desktop. Some work remains to be done on DOS program launching, because the startup directory is not always correctly determined and filenames in the command line are not yet translated out of the mounted directories. It cannot launch Windows programs at all under Windows 3.x, though it can be done in some circumstances under Windows 95/98.
** Keyboard **
The method used for detecting and reporting keypresses is unique, and seems to be mercifully free from the glitches and lockups that plague at least two other emulators. There are two limitations: first, programs wanting to sense more than one alphanumeric key being held down at a time cannot do so, but that is a very uncommon practice except in games anyway; second, the mouse cannot be 'clicked' from the keyboard using alt-insert or alt-home, though the alt-arrows work.
If you configure Tosbox so that kbrate is enabled, the control panel is allowed to change the keyboard delay/repeat settings, and Tosbox attempts to restore the original values on exit. Since some PCs do not allow the settings to be read reliably, the keyboard settings are tied to the host PC's settings by default.
Some of the PC special keys are mapped as follows (note that control+[Left shift]-Q can be redefined according to your preference during configuration):
| page up | shift - up arrow |
| page down | shift - down arrow |
| end | shift - right arrow |
| shift - end | shift - left arrow |
| F11 | Help |
| F12 | Undo |
| cntrl - break cntrl - [Left shift] -Q |
{stop the emulator} |
| alt - end | {manually refresh screen after a floppy swap} |
| home | {mode dependent - see below} |
The IKBD clock is read-only, and implemented at the XBIOS level.
With NumLock off, the numeric keypad works as it normally would in DOS.
The Home key can work in two different modes. By default, it behaves like the standard Atari Clr/Home key. Also available is a native PC mode that makes Home the intuitive counterpart of End: just as End normally maps to shift+right, Home then maps to shift+left. This only applies when no modifiers (shift, control, alt) are used. To make the emulated ST see a normal unshifted Home key while in this mode, press control+shift+home.
You can switch between the default and PC home key modes at any time, by pressing shift+shift+Home. You can also choose during configuration whether to make PC mode the default when Tosbox starts.
** International keyboard adjustment **
To improve keyboard behavior on machines set up for languages other than English, or whenever the ST bios language setting does not match that of the host PC, configure Tosbox to use the "Auto ASCII" option.
** Mouse **
A mouse driver must be installed before Tosbox runs. In most situations you don't need to worry about this. But if you find that the Tosbox mouse pointer can be moved when running from Windows but not from DOS, you need to install a DOS-mode mouse driver. Consult the FAQ for instructions.
For better compatibility with certain unusual mouse drivers, Tosbox no longer refuses to run when it cannot immediately detect a driver, though it does briefly display a warning message. You will only know for sure that there is a problem if the mouse pointer refuses to be moved.
If you are using Linux DOSEMU under X-windows (command "xdos"), dosemu's internal mouse driver works quite nicely so long as you specify mouse type 4 ("Linux/DOSEMU") in the Tosbox setup program.
** Serial port **
The ST serial port is emulated at the hardware level. It can be mapped to any of the four PC COMx: devices, at speeds up to 115200 baud. Flow control is supported in hardware (RTS/CTS), as are the DCD, DTR and Ring Indicator lines and their associated interrupts. Because Atari never quite got it right in TOS, proper use of RTS/CTS requires installation of a patch program in the AUTO folder; I've had good luck with SERIALFX.
Users in England, and nowhere else as far as I know, have reported difficulty establishing PPP and SLIP connections. I acknowledge the problem but don't know where to begin fixing it, since it can't be reproduced here.
** Parallel (printer) port **
In the beta versions of Tosbox, the parallel port was emulated at the hardware level only. That code is still in place, but from version 1.00 onward, the GEMDOS and BIOS calls that speak to the parallel port do so directly, with the result that they are now almost as fast as writing to the hardware registers.
You may at first experience significant delays in printing because of the way Windows spools DOS printer output; if you don't like this behavior, there are three known solutions.
1. When configuring Tosbox, assign the virtual parallel port to the default system printer, (prn: flushed). Tosbox will flush and release the printer device whenever a short delay has elapsed since the last information was sent by your program. Besides just giving you more reasonable printer response times, using prn instead of lptx for the ST parallel port has these advantages:
TBC.ACC accessory allows you to also flush the printer manually, in case you ever need to do that.2. Or, modify your \WINDOWS\SYSTEM.INI file to contain these lines:
[Network] PrintBufTime=5
[ifsmgr] PrintBufTime=5
An easy way to edit this file is to select "Run..." from the W95/98 Start menu and type "SYSEDIT". If the [Network] and [ifsmgr] groups do not exist in SYSTEM.INI, add them just after the [386Enh] section. The parameter "5" here determines the idle time between automatic flushes of the Windows print queue. Values between 1 and 10 may be desirable; the default is much higher, reportedly 45 seconds. Windows typically treats DOS programs as batch jobs, so such a long delay is assumed to help such programs get done with their work and exit more quickly.
3. Or, in Windows 95/98, open your "Printers" folder from the control panel, right-click on the printer you are using, select "properties", then "details", then "spool settings", then "print directly to printer." But this means you lose the capability of spooling print data within Windows, which is likely to be undesirable, depending on what sort of printer you have and what kind of work you do.
** Sound **
There is limited sound support. Only the predefined system sounds are emulated (the error bell and keyclick). You may configure Tosbox so that those sounds are disabled, or played through the PC speaker, or played through a Soundblaster-compatible card.
The Soundblaster-rendered error ping did not work properly on some SB clone cards before version 1.10. This was because the ping sound used a single operator tone (modulator with no carrier). The Soundblaster mode built into the FIC VA-503A motherboard, at least, does not support this. So two operators are used in version 1.10.
** Missing features **
There are no plans to support sound or joysticks; get PaCifiST if you need those. The IKBD command $16 (send single joystick report) is hardwired to return "joysticks centered, fire buttons not pressed".
General sound chip emulation may possibly be included someday, if there is enough interest and I find enough time. (Note, May 2000: this is looking highly unlikely.)
Also there are no plans to emulate the MIDI ports, a 68030 CPU, or any machine-specific hardware.
** Detecting the presence of Tosbox **
The approved method, a la PaCifiST, is to call Vsync() with D6 = D7 = 'Emu?' ($456D753F). On return, D6 will contain 'TBox' ($54426F78) and D7 will contain the ASCII-encoded version number.
Programmers who don't use assembly can get the same information from ST memory locations $3f0 and $3f4, unless some application has thoughtlessly polluted that area.
All the users who have registered, or helped with debugging, or conveyed their encouragement;
Dan Wilga, for helping me read the entrails of GEMDOS and offering some welcome advice
Sam Vincent, for the SVAsync library, around which the serial emulation is built;
and DJ Delorie and Robert Hoehne, for their work on DJGPP and RHIDE respectively.