VirtualBox是一款免费且开源的虚拟化软件，允许用户在他们的计算机上创建和运行虚拟机。使用VirtualBox，用户可以在他们的计算机上同时安装和运行多个操作系统，而无需创建单独的分区或购买额外的硬件。

VirtualBox的主要优点之一是易于使用。即使是对虚拟化技术几乎没有经验的人，它也很容易安装和设置。VirtualBox还提供了广泛的自定义选项，包括调整分配给每个虚拟机的RAM、CPU核心和硬盘空间的能力。

VirtualBox的另一个重要特点是其与多种操作系统的兼容性。用户可以在他们的虚拟机上安装和运行Windows、Linux、macOS及许多其他操作系统。这使得它成为一个对开发人员、软件测试人员以及任何需要在单台计算机上运行多个操作系统的人来说非常优秀的工具。

VirtualBox 还提供了一系列高级功能，例如对 USB 设备、共享文件夹和网络适配器的支持。这些功能使得运行需要硬件或网络资源的软件成为可能，例如虚拟路由器、防火墙和服务器。

VirtualBox 是任何需要在一台计算机上运行多个操作系统的人的绝佳选择。其易用性、广泛的自定义选项以及与许多不同操作系统的兼容性，使其成为开发人员、IT 专业人员和家庭用户的多功能而强大的工具。

关键功能：

• 跨平台兼容性。
• 直观的图形用户界面。
• 支持各种操作系统。
• 与主机操作系统的无缝集成。
• 快照和克隆。
• 网络功能。
• 虚拟设备支持。
• 扩展包用于增加功能。

• VMM: another TLB invalidation fix for non-present pages
• VMM: fixed a performance regression (4.2.8 regression; bug #11674)
• GUI: fixed a crash on shutdown
• GUI: prevent stuck keys under certain conditions on Windows hosts (bugs #2613, #6171)
• VRDP: fixed a rare crash on the guest screen resize
• VRDP: allow to change VRDP parameters (including enabling/disabling the server) if the VM is paused
• USB: fixed passing through devices on Mac OS X host to a VM with 2 or more virtual CPUs (bug #7462)
• USB: fixed hang during isochronous transfer with certain devices (4.1 regression; Windows hosts only; bug #11839)
• USB: properly handle orphaned URBs (bug #11207)
• BIOS: fixed function for returning the PCI interrupt routing table (fixes NetWare 6.x guests)
• BIOS: don't use the ENTER / LEAVE instructions in the BIOS as these don't work in the real mode as set up by certain guests (e.g. Plan 9 and QNX 4)
• DMI: allow to configure DmiChassisType (bug #11832)
• Storage: fixed lost writes if iSCSI is used with snapshots and asynchronous I/O (bug #11479)
• Storage: fixed accessing certain VHDX images created by Windows 8 (bug #11502)
• Storage: fixed hang when creating a snapshot using Parallels disk images (bug #9617)
• 3D: seamless + 3D fixes (bug #11723)
• 3D: version 4.2.12 was not able to read saved states of older versions under certain conditions (bug #11718)
• Main/Properties: don't create a guest property for non-running VMs if the property does not exist and is about to be removed (bug #11765)
• Main/Properties: don't forget to make new guest properties persistent after the VM was terminated (bug #11719)
• Main/Display: don't lose seamless regions during screen resize
• Main/OVF: don't crash during import if the client forgot to call Appliance::interpret() (bug #10845)
• Main/OVF: don't create invalid appliances by stripping the file name if the VM name is very long (bug #11814)
• Main/OVF: don't fail if the appliance contains multiple file references (bug #10689)
• Main/Metrics: fixed Solaris file descriptor leak
• Settings: limit depth of snapshot tree to 250 levels, as more will lead to decreased performance and may trigger crashes
• VBoxManage: fixed setting the parent UUID on diff images using sethdparentuuid
• Linux hosts: work around for not crashing as a result of automatic NUMA balancing which was introduced in Linux 3.8 (bug #11610)
• Windows installer: force the installation of the public certificate in background (i.e. completely prevent user interaction) if the --silent command line option is specified
• Windows Additions: fixed problems with partial install in the unattended case
• Windows Additions: fixed display glitch with the Start button in seamless mode for some themes
• Windows Additions: Seamless mode and auto-resize fixes
• Windows Additions: fixed trying to to retrieve new auto-logon credentials if current ones were not processed yet
• Windows Additions installer: added the /with_wddm switch to select the experimental WDDM driver by default
• Linux Additions: fixed setting own timed out and aborted texts in information label of the lightdm greeter
• Linux Additions: fixed compilation against Linux 3.2.0 Ubuntu kernels (4.2.12 regression as a side effect of the Debian kernel build fix; bug #11709)
• X11 Additions: reduced the CPU load of VBoxClient in drag'and'drop mode
• OS/2 Additions: made the mouse wheel work (bug #6793)
• Guest Additions: fixed problems copying and pasting between two guests on an X11 host (bug #11792)