a handle larger than 16384 by the GDI system crash and terminate with an error message. In general, VDM and similar technologies do not satisfactorily run most older DOS games on today's computers. Emulation is only provided for the most basic peripherals, often implemented incompletely. For example, sound emulation in NTVDM is very limited. NT-family versions of Windows only update the real screen a few times per second when a DOS program writes to it, and they do not emulate higher resolution graphics modes. Because software mostly runs native at the speed of the host CPU, all timing loops will expire prematurely. This either makes a game run much too fast or causes the software not even to notice the emulated hardware peripherals, because it does not wait long enough for an answer. Absence in x64 and AArch64 In an x86-64 CPU, virtual 8086 mode is available as a sub-mode only in its legacy mode (for running 16- and 32-bit operating systems), not in the native 64-bit long mode. NTVDM is not supported on x86-64 editions of Windows, including DOS programs, because NTVDM uses VM86 CPU mode instead of the Local Descriptor Table in order to enable 16‑bits segment required for addressing. NTVDM is also unavailable on AArch64, because Microsoft did not release a full emulator for this incompatible instruction set like it did on previous incompatible architectures. Whilst NTVDM is not supported on x86-64 versions of Windows, they can still be run using virtualization software, such as Windows XP Mode in non-home versions of Windows 7 or VMware Workstation. Other methods include using NTVDMx64, an unofficial port of the leaked emulated implementation of NTVDM from Windows NT 4.0 for non-x86 platforms, or OTVDM (WineVDM), a 16-bit Windows interpreter based on MAME's i386 emulation and the 16-bit portion of the popular Windows compatibility layer, Wine. See also Comparison of platform virtualization software DESQview 386 (since 1988) Wine (software) DOSBox DOSEMU Merge (software) List of Microsoft Windows components Hypervisor Windows on Windows (WoW) Virtual machine (VM) Notes References Further reading External links Virtual DOS Machine Structure Troubleshooting MS-DOS-based programs in Windows XP Troubleshooting an MS-DOS application which hangs the NTVDM subsystem in Windows XP and Windows Server 2003 Troubleshooting MS-DOS-based serial communication programs in Windows 2000 and later MS-DOS Player for Win32-x64, a Microsoft MS-DOS Emulator, runs many command line DOS programs like compilers or other tools, also packaged into one