DOS extender
Phar Lap’s product line was expanded to include "386|VMM", a virtual memory add-in driver, "LinkLoc", a linker-locator for embedded development; cross tools for embedded development; and "286|DOS-Extender", a DOS extender that emulated an OS/2 environment, complete with the OS/2 API and protected mode, in contrast with Microsoft's OS/2 API emulation, which ran OS/2 applications in real mode and only supported a subset of the OS/2 API, called the Family API. Therefore, it was often bound with existing OS/2 applications, replacing Microsoft's OS/2 API emulation for those applications that needed access to extended memory in DOS. Later on the "TNT" DOS extender was created, which was a version of "386|DOS-Extender" that emulated the Win32 environment, complete with flat address space and threading. Again this DOS extender was often bound to existing Win32 applications. Unfortunately, MASM 6.1 and the 16-bit version of the Visual C++ 1.0 compiler were Win32 applications written for a beta version of Windows NT that was bound with the "TNT DOS Extender", which means it could not run on the final version of Windows NT until Beta2Fix.exe was run, which replaced all references to NTDLL.DLL with BETA2.DLL. This was fixed in MASM 6.11 and Visual C++ 1.5.