Editing Virtual PC (section)

== Emulated environment ==
Virtual PC emulates the following environments:<ref name="NNtEa">{{cite web|work=Microsoft.com|title=Overview of the technical specifications of virtual machines in Virtual PC 2004|date=October 27, 2004|access-date=May 23, 2010|url=http://support.microsoft.com/kb/833144|archive-date=March 28, 2010|archive-url=https://web.archive.org/web/20100328153230/http://support.microsoft.com/kb/833144|url-status=live}}</ref>
* [[Intel]] [[Pentium II]] ([[32-bit]]) processor (but virtualizes the host processor on Windows versions) with an [[Intel 440BX]] chipset (with [[PIIX]]4E southbridge).
* Standard [[Super video graphics array|SVGA]] [[Video Electronics Standards Association|VESA]] [[video card|graphics card]] ([[S3 Trio#Variants|S3 Trio32]] [[Peripheral Component Interconnect|PCI]] with 4 [[megabyte|MB]] [[Video RAM (dual-ported DRAM)|video RAM]], adjustable in later versions up to 16&nbsp;MB by manually editing a virtual machine's settings file).
* System [[BIOS]] from [[American Megatrends]] (AMI).
* [[Creative Technology Limited|Creative Labs]] [[Sound Blaster 16]] [[Industry Standard Architecture|ISA]] [[Plug and play|PnP]]. (When Windows Vista is installed as both the host (main) and guest (virtual) operating systems, settings are synchronized with the host and audio configuration is not required.)
* [[Digital Equipment Corporation|DEC]] 21041 (DEC 21140 in newer versions) [[Ethernet]] [[computer network|network]] card.
* Programs using undocumented features of hardware, exotic timings, or unsupported [[opcode]]s may not work.

Implementation:
* The [[Apple Macintosh|Macintosh]] version of Virtual PC uses [[dynamic recompilation]] to translate the [[x86]] code used by PCs into equivalent [[PowerPC]] code for Macs.
* The Windows version of Virtual PC also uses dynamic recompilation, but only to translate x86 [[kernel mode]] and [[real mode]] code into x86 [[user mode]] code; original user mode and [[virtual 8086 mode]] code run natively.
* Guest call traps are used, especially for guest extensions, to accelerate emulation or offer additional features, such as integration with the host environment.
* Virtual PC and [[Microsoft Virtual Server|Virtual Server]] encapsulate virtual hard disks in the [[VHD (file format)|Virtual Hard Disk]] (VHD) file format, for which Microsoft has made all documentation available under the [[Microsoft Open Specification Promise|Open Specification Promise]].

Virtual PC 4 requires Mac OS 8.5 or later on a G3 or G4 processor, but running [[Windows Me]], [[Windows 2000]] or Red Hat Linux requires Mac OS 9.0 or later. Virtual PC 5 requires [[Mac OS 9.1]] or newer or [[Mac OS X 10.1]] or later.  For USB support, Mac OS X is recommended. To run Virtual PC 5 in Mac OS X, a 400&nbsp;MHz or faster [[CPU|processor]] is required.

Earlier versions of Virtual PC supported the following features: (now removed in Microsoft Virtual PC 2004, 2007, and Windows Virtual PC):
* Older versions of Virtual PC (v5.0 or earlier) may have the hard disk formatted after creating the [[VHD (file format)|Virtual Hard Disk]] file. Newer versions must partition and format the [[VHD (file format)|Virtual Hard Disk]] file manually.
* A ''Virtual Switch'' available in Virtual PC version 4.1 or earlier allows adding multiple network adapters.
* Older operating systems are supported with Virtual Machine additions.
* Older versions of Virtual PC for Macintosh can run on Mac OS 9.2.2 or earlier. Support for [[System 7#Version history|System 7.5]] was dropped in version 3.