The Win32s compatibility list

1. Definition of Win32s
2. Downloading Win32s
3. Which programs are likely to run with Win32s
4. What the reasons can be if programs don't run
5. The list itself: Apps that are compatible with Win32s
6. NEW:Windows NT 3.51 compatibility

Before we begin: What's Win32s anyway?
Win32s is an extension for 16-bit Windows (3.1x) that allows the execution of 32-bit programs originally written for 32-bit Windows versions, such as NT 3.x, 4.0 and Win 9x. But please do not assume that every 32-bit program will actually run on Win32s: originally it was only designed for compatibility with NT 3.x, and only a subset of the Win32 API is supported (that's why it's called Win32s)! By the way: 16 and 32 bit apps can exchange data over the clipboard and use OLE functions (which means that you can put an image that has been created in Paint Shop Pro 3.12 32-bit into your Winword 6.0 document and edit the image in PSP when necessary; this only works if PSP is registered as an OLE server though).

Download of Win32s
Win32s 1.30c can be downloaded here:
It's about 2.5 MB in size and comes with a 32 bit Help program, which is very useful, as it is a functional equivalent of the Help program of Windows 95; it can even read Win95 help files. Also included is a little game called Freecell, mainly for test purposes. And last but not least, the latest OLE files (v2.03) come with Win32s as well - OLE functionality must come from somewhere ;).

What kind of program is more likely to run on Win32s?
Multi-platform software is more likely to work with Win32s, such as the image viewer XNView (freeware, more than 100 formats), the math software Maple V (until Rel. 4; Rel. 5: Single-user version only), the raytracer POV-Ray (until V. 3.02, Win32s support dropped for V. 3.1; freeware), and, as I've been told, Adobe Photoshop until V.4. And of course we mustn't forget the kind of programs Win32s was originally intended for: a host of Win NT 3.x software (well, "host of software" may be a "bit" exaggerated...;).

Why are there so many programs that don't run on Win32s?
There are a number of reasons.

To summarize:
The programmers must address Win32s specific problems; for example, good memory management is necessary to prevent resource leakage. That means extra work, of course. Additionally Win32s needs program and DLL sections that can be omitted in Win9x/NT. Another reason is that all the newer development tools do not support Win32s anymore (the last MS Win32 SDK that ships with Win32s is from 1996, for example), and today's compilers' defaults are usually incompatible to Win32s as well.

Now the details:
If a program uses Win9x specific functions of any kind, multi-threading, relies on fixed addresses (meaning that it lacks relocation tables) or simply uses Win32 functions that aren't implemented in Win32s, then it won't work. In case of lacking relocation tables Win32s simply doesn't understand the format of the executable (resulting in an "Invalid format" message). The registry database is another problem, especially if the program's keys contain spaces (" "). Console mode apps can run if they're well-written (e.g. have relocation tables etc.), but there are no output possibilities, which means that one can't see what the program is telling the user, including help texts, unfortunately. Additionally, they must be started from Windows; unlike in Win9x, starting them directly from a DOS box doesn't work. Examples of working console mode apps are the Win32 console mode version of the web server Xitami 2.4d7 and the image converter NConvert which comes with the Win9x/NT version of XNView (which BTW, is identical to the "Win 3.x" version, except for other language DLLs).

For further enlightenment I've cited from various posts from Paul Chitescu (hope he doesn't mind):

[comments in italic]

(Date: Wed, 30 Jun 1999 16:53:38 +0400
 Forum: microsoft.public.win3x_wfw_dos)

Top reasons why a 32-bit applications won't run on Win32s :

As a general rule, well written applications have more chances to run on Win32s. I managed to run (up to a point) MS Word 95 and Excel 95 under Win32s - and those are heavy programs. Why such an application can run and a pityful applet that strips the Internet cache can't - answer yourself.

In the same message he wrote about his modified version of shell32.dll:

Many applications are not using purely Win32 API but also '9x specific ones. MS had to add some things to his NT 4 to keep such applications running (remember DirectX ?)

What I've done is a rewrite of the SHELL32.DLL that came with Win32s ersion 1.30C (that is, build 172). I disassembled that file and copied low-level thunking code as-is, except I stripped unreferenced setjmp() and longjmp() (Note: How did they link them there anyway ?).

[Direct download link for his modified version of shell32.dll]

I've written a DLL that extends this version of SHELL32 by implementing Shell_NotifyIcon() (both A and W, I've found later that 9x implements only the ANSI version) and SHAppBarMessage(). When I have more time I will implement more SHxx functions.
[I'll ask him if he can put it in his user page's software directory]

In another post in the same newsgroup (dated Thu, 17 Feb 2000 12:29:45 +0200), he wrote the following about memory management in Win32s:

[Someone had encountered an Error 21/"Invalid Format" message from Win32s]

Unfortunately the VC++ 5 and 6 compilers default to not generate a .reloc section in applications so the .EXE can be loaded only at its fixed base address (default 0x400000) that is not available in Win32s.

There's no way around this error because of the different memory organization in Win32s where all programs share the memory in a single virtual machine. In a true Win32 environment each 32bit application gets its own virtual machine in which all the address space is free.

Here's my little list of compatible apps ("mp" means multi-platform software):

Especially "friendly" apps are marked ":)". Programs that are also friendly, but which suffer from minor problems (difficult installation, resource eating or slight instabilities), are marked ":|". Programs suffering from major instabilities (thus being only useful for experiments) are marked ":(". The third category is constituted by programs not intended for Win32s (as you may imagine). Smileys in brackets mean "not sure". Question marks stand for "unknown". The license types are COM (commercial [payware]), COM/DEMO (commercial, w/ demo version), FREE (freeware), SHR (shareware).
Note: Many thanks to Gaby Chaudry, who has added quite a few programs in the past :).
Company Software / Version License "Friendli- ness" Stability Problem(s) Solution to the problem(s) Installable under Win32s Intended for
Adobe Photoshop until 3.x COM :) Good Installer may give trouble by crashing in module <unknown> (v3.0) Try installing with a minimum Windows config Yes Any Win32 (mp)
Adobe Photoshop 4 COM [:|] Said to be less fast and stable Resource hog -- Yes Any Win32 (mp)
Ahead Software GmbH Nero Burning ROM (until, newer versions: support dropped) COM/ DEMO :) Good Does only support SCSI CD-R drives, slight display problems, with SCSI burning problems seem to be anything but rare 1st problem: Not found yet :-( Yes Any Win32
Ajuba Solutions Tcl/Tk 8.0p2 FREE :) Good Minor incompatibilities -- Yes Any Win32 (mp)
Aladdin Ghostscript 6.01, GSview 3.6 FREEWARE COM/ FREE :| Good Difficult install, some utility programs don't run on Win32s RTFM Yes Any Win32
Alchemy Mindworks Inc. GIF Construction Set 95 1.0L SHR :) Good May complain about missing DLLs It's not impossible to get those, though ;) Yes Windows 95
Corel Corp. CorelDEPTH 6.0 COM :| Good Missing key in the registry database Execute this registry editor with the parameter /V and add the key (HKCR is root directory, all others are the same as HKCR) No, click here for dir list and ini file excerpts Win 95
Corel Corp. CorelDREAM 3D 6.0 COM :| Good Same as above Same as above No, click here for dir list and ini file excerpts Win 95
Daniel Hyams Curve Expert 1.3 SHR :| Good Replaces CTL3D32.DLL. Help doesn't work, may cause a crash if executed anyway. Make a backup copy of CTL3D32.DLL before installing, and write it back afterwards. Yes Any Win32
Dommelsch Roll'm up FREE :| Good crashes when leaving program or trying to load highscore list (i.e. 'Game over' really means 'game over'....) None Yes Win95
FMJ Software Awave 3.0 SHR :) Good may crash when used with incompatible sound card none Yes Any Win32
Funduc Software Inc. Search and Replace for Win95/NT SHR [:)] Good ? -- Yes Win 95/NT
Gekko Software Kalua Cocktails 98 DEMO :) Good Occasionally shows error messages. Sound effects don't work (depending on sound card?). ignore error messages Yes Windows 9x
Gilles Vollant WinImage 5.0 SHR :| ? Caused a few system lockups while reading floppies here - no clue why ? Yes Any Win32
Guardian Software Productions Patrick Cornelißen SoundGuard 2.0 SHR :| Good starts up with error messages (ignore them) and cannot be closed normally use a taskmanager or other program that can kill the problem(s)          processes to close the application Not needed Any Win32
Hamrick Software VuePrint Pro/32 7.6e SHR :) Good None as yet -- Yes Any Win32
HeadLight Software GetRight 1.3b SHR :) Good Does not always work with Trumpet Winsock, some fiddling with proxy servers required (only if you use one, of course) Make sure Win32s's wsock32.dll is used Yes Any Win32
Helios Software Solutions TextPad32 1.30 SHR :) Good None -- Yes NT 3.x
iMatix Corp. Xitami 2.4d7 Win32 console mode version FREE :) Good Console mode, so there's no output none Yes Any Win32 (mp)
Ipswitch WS_FTP Pro 6.0 COM :( Good Profile manager hangs ? Yes Win95/NT
Ipswitch WS_PING32 ? [?] ? Some display problems none ? ?
Ipswitch WS_PingProPack 2.10 COM :) Good none -- Yes Win95/NT
Ipswitch WS_WATCH FREE :) Good Some display problems, wants to use MS icmp.dll none; insert line "ms_icmp.dll=0" into %windir%\ws_watch.ini to force using rs_icmp instead Yes Any Win32
JASC Inc. Paint Shop Pro 3.12 SHR :) Good; very stable Will not show the properties of PNG images in the Open File dialog if they have been created by PSP itself none (the bug does not only occur under Win32s) Yes Any Win32
Jeff Parker Memory Status 1.1 FREE :) Good Small resource leak -- Yes Any Win32
Jerome Tremblay Window HTML 1.1 FREE :) Good produces long file name associations in the HTML files edit the HTML code... Yes Windows 9x
Lars Hederer CabPack 1.3 FREE :) Good None -- Yes Windows 9x
Leonardo Loureiro LView Pro 1.D2 32-bit SHR :) Good None -- Yes Any Win32
? mIRC 5.6 ? [?] ? Config dialog uses lots of resources Configure mIRC when enough resouces are free Yes ?
Micrografx Picture Publisher 6.0 COM :( Mediocre Registry (does not save settings), startup screen won't go away, new window opened at startup For startup screen: Find the dialog box under the startup screen, move it away and close it.
Otherwise: None, use for experiments only.
No Win 95
Microsoft FontView (from Win95's Quick Viewer) COM :) Good none -- No Win95
Microsoft Help compiler v4.0.213 COM [?] it works ? -- ? Win 95/NT (?)
Microsoft MS-Info32 (from Office 95) COM [?] ? ? -- Probably not Win 95/NT
Microsoft OLE2 viewer (Win95 SDK, Visual C 2.0) COM [?] it works ? -- ? Win 95/NT (?)
Microsoft Windows 95 calculator COM :) Good none -- Not needed Win95
Microsoft Various W95 screen savers (the "standard" ones, such as flywin, marquee, mystify etc.; 32-bit flywin runs _much_ more smoothly), except for bezier.scr COM :| Good Settings aren't saved Keep Paul Chitescu's Enhanced Registry Editor open. Install not needed Win 95
Microsoft Windows 95's Wordpad COM :( Not all that good Ruler doesn't work, crashes on opening / saving files (IIRC) You need the Win32s compatible msvcrt20.dll and the MFC 3.0 DLLs Install not needed Win 95
Mirabilis ICQ 1.111beta FREE :| Good Sometimes problems when communicating with newer versions, installs Win32s incompatible msvcrt40.dll, doesn't seem to work with IE 3.02's dialer, crashes on startup if Netscape is already running (resource shortage?), no longer works due to protocol changes? DLL problem: Replace with the correct version; otherwise: none Yes Any Win32
<Development group> POV-Ray 3.02 (3.1 upwards: support dropped) FREE :| Good System hangs when POV-Ray restarts itself If settings need a restart, change them manually in the pvengine.ini file. Yes Any Win32 (mp)
Photodex CompuPic 4.00 build 963 SHR :( unstable crashes often, uses up nearly all the resources none Yes Win95/NT
Pierre-e Gougelet XNView 1.25 ("Win 3.x" version) FREE :| Good V1.07 didn't like Instant File Access; the versions 1.11 and 1.12 had a resource leak; the file browser in new versions is pretty resource hungry Use standard dialog instead (V1.07); resource leak fixed in 1.14 Not needed Any Win32 (mp)
Pierre-e Gougelet NConvert (included w/ XNView 1.15 for Win9x/NT) FREE :) Good Console mode, so one doesn't see what happens none Not needed Any Win32 (mp?)
RarSoft WinRAR 2.02 SHR [?] ? ? -- ? Win95/NT
Raihan Kibria frhed - free hex editor 1.0.156 FREE :) Good none -- Not needed Any Win32
Raphael Molle WinVi 2.90 (32bit version) FREE :) Good About dialog doesn't work none / use 16 bit version :) Not needed Any Win32
Siegfried Weckmann SWInfo 3.04 FREE :| Good only partially usable because of incorrect output none Yes Win95
Smartdraw Smartdraw 3.23 COM :) Good Installer says the program doesn't work with Win 3.1x (this is wrong) -- Yes Win95/NT
Todd C. Wilson MapThis! 1.3 FREE :) Good none -- Yes Any Win32
UR Soft W32Dasm 6.4 COM/ DEMO :| Rather mediocre Crashes now and then, but Win32s can intercept the crashes; resource eater none Not needed Any Win32
Vincenzo Iuorno Lookdisk 2.5 FREE :) Good None -- Yes Any Win32
Vulcan Technology Vulcan Notes 2.13 SHR :) Good None so far -- Yes Win95/NT
Waterloo Maple Maple V Rel. 5 Single-user COM :| Good Collides with All3D; uses 36% of GDI resources Do not add any 3D effects to wmaple.exe in Control Panel >> All3D; Maple uses them by itself, which then leads to a system hang Yes Win95/NT4+, Win32s (mp)
Waterloo Maple Maple V Rel. 4 COM [:)] Not extensively tested None, seems to use less resources (~17%) -- Yes Any Win32 (mp)
XATech JPEG Optimizer 1.31 SHR :| Good it's impossible to close the program because of a persisting error message use the task manager to exit the program No Win95
XATech JPEG Optimizer 3.15 SHR :( Good it's impossible to close the program because of a persisting error message; help doesn't work (may even crash the system); all features available in unregistered version, but the new ones (vs. 1.31) disappear when the registering code is entered!? use the task manager to exit the program No Win95
Yuri Software HEdit32 v1.2 SHR :) Good None -- Yes Any Win32 (Win NT 3.1)

1. Newer RegEdit (probably from Win NT 3.51)
2. Paul Chitescu's Enhanced Registry Editor
3. Paul Chitescu's modified shell32.dll with better stability and the Win 95 icons
4. The version of msvcrt20.dll that is compatible with Win32s
5. The Win32s compatible version of msvcrt40.dll
6. WW1000: Updated vshare.386 (Winhlp32 now works without share.exe)

I have some localized (=translated) Win32s 1.30c DLLs, but I'm not going to upload them, as they are quite large (German language files: approx. 607 KB zipped). If you'd like to have Danish, German, Spanish, Finnish, French, Italian, Dutch, Norwegian or Swedish DLLs and Winhlp32, just write to me and I will send them to you.

Windows NT 3.51 compatibility
One could call NT 3.51 "Win 3.1 on steroids", and there certainly is some truth to that. However, under the 3.1-ish hood it doesn't bear too much resemblance to plain Windows 3.1x - it's a 32 bit operating system which supports true preemptive multitasking, multithreading, SMP operation (NT Workstation: up to 2 CPUs, NT Server: up to 4 CPUs, NT Advanced Server: up to 8 CPUs), OpenGL acceleration (3D stuff), Unicode character sets/fonts and which runs much more stable than "consumer-grade Windows" (partly due to virtually not having those nasty resource limits that drive you nuts in 3.1x). Weaknesses are relatively few: No power management support, no support for plug and play (don't try removing PCMCIA cards when it runs!), only very limited (and thus virtually useless) DCI video acceleration. As you can see, it's not without a reason that the NT variants are called "Workstation" and "Server" - these names describe best where NT is able to play out its strengths (or the other way round: where its weaknesses don't matter much): office computers, graphic workstations (well, at least back then) and servers. Obviously it's not an ideal choice for multimedia or notebook computers. (This only changed with Windows NT 5.0 a.k.a. Windows 2000.)
Considering its 1995 release date (and 32 bit nature), it isn't all that amazing that Windows NT 3.51 is more demanding than plain 3.1x: 16 MB of RAM are the bare minimum, though even 24 megs will only allow operation of contemporary software (like Netscape 4.08) with lots of swapping; with 48 MB it's a lot better. Having become the proud owner of a dual Pentium 90 machine recently (Gigabyte GA-586DX rev. 3B, 48 (originally 24) megs of RAM from my old P75@90, a 540 meg hard disk, spare ELSA 2 meg PCI graphics card, 10 MBit PCI NIC), I decided to try NT 3.51 on it ('cuz it's "the OS I've always wanted to check out"). It seems that this elderly OS has largely been abandoned, and quite a few newer apps will not run on it. (IMO this is a pity - it's a quite nice, stable OS.) The reasons for this are partly similar to those with Win32s:

So it's time for a compatibility list, don't you think?
Company Software / Version License Stability Problem(s) Solution to the problem(s) Installable under NT 3.51 Intended for
Adobe Acrobar Reader 3.01 (32-bit) FREE Good none noted; later versions don't work -- Yes Win 95/NT
CompCore SoftPEG 2.21 COM (*) Good Mplayer.exe from VfW 1.1 is needed; no video acceleration -- Yes Win 3.1x/95
Eberhard Backeshoff, DK8JV JVComm32 1.21 SHR Mediocre The self-extracting distribution ZIP archive doesn't want to run; app crashes as soon another mode than "None" is selected (probably window creation fails), which pretty much makes it useless Use WinZip to extract the files and run setup.exe; none (No) Win95/NT4+
GIMPS Prime95 v21 FREE Good None, great stability test (and you can make math history by finding a Mersenne prime :) -- Yes Win95/NT
JASC Inc. Paint Shop Pro 3.12 SHR Good; very stable Will not show the properties of PNG images in the Open File dialog if they have been created by PSP itself none (the bug does not only occur under NT 3.51) Yes Any Win32
Jeff Parker Memory Status 1.1 FREE Good None -- Yes Any Win32
Juoni Vuorio CPU Stability Test 6.0 FREE Good None -- Yes Win95/NT
Markus Oberhumer, Laszlo Molnar UPX 1.20w FREE Good None -- Yes Win95/NT
Microsoft TZEdit (Win95 Kerneltoys) FREE Good none -- Yes Win 95
Netscape Communications Corp. Communicator 4.08 (32-Bit), 4.51, 4.7, 4.73 FREE Good No probs with these, but 4.78 did *not* work (obviously a sign of the 3rd party maintenance - NT 4.0+ kernel functions required) Installing the OLE automation update oadist2z.exe and other updates might not be a bad idea in case you experience any trouble with older versions Yes Win95/NT (mp)
Nico Mak Computing Inc. WinZip 7.0 SR-1 SHR Good Will not run EXE files from within archives, since they're not associated with anything in NT 3.51; 8.0+ versions don't work Use Regedt32 to set up the .EXE file type like in Win9x/NT4+ ? (I'm lazy and copied the whole directory over the network ;) Win95/NT
Opera Software Opera 3.62 32-bit SHR OK A bit too crashy for my taste, but the 16-bit version isn't any better; file dialogs don't work (CommDlg extended error 0x2) None Yes Win95/NT
Opera Software Opera 4.01 SHR Good Slight display problems, same dialog problem as with 3.62; both 5.12 and 6.01 gave considerable trouble (common control issues, I guess) and are not to be recommended None Yes Win95/NT
Pierre-e Gougelet XNView 1.25 ("Win 3.x" version) FREE Good Language files aren't loaded?! none so far Not needed Any Win32 (mp)
Raphael Molle WinVi 2.90 32-bit FREE Good None -- Yes Any Win32
Thong Nguyen PowerMenu 1.50 FREE Good Growing number of "Priority" menus; "Minimize to tray" minimizes to nowhere since there is no system tray (tip: use a good Win 3.1x task manager to unhide the window) None Yes Win95/NT4+
Waterloo Maple Maple V Rel. 5 Single User COM Good Requires use of Win32s files with Win32 msvcrt40.dll Copy whole Maple directory from a 3.1x computer, rename msvcrt40.dll to .dlx or similar No Win95/NT4+, Win32s (mp) AG WebWasher 3.2 beta 3 FREE Good Configuration dialog has some display issues: menus with empty captions and empty (but working) items, some displayed items like the local proxy port entry field are beyond the right border No fix, app works fine within the given limitations (Winsock 1.1, full functionality only available with Winsock 2.0) Yes Win95/NT4+
Xing XingMPEG 1.4 COM (*) Good Mplayer.exe from VfW 1.1 is needed (possibly the whole package); no video acceleration -- Yes Win 3.1x

(*) Software has been abandoned and there are several free downloads because of it having been bundled with graphics cards

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Created 08/07/1999 (dd/mm/yyyy)
Last revision: 2002-04-02 (yyyy-mm-dd)