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: fixed restoring 32-bit FPU state on 64-bit capable VMs and restoring guest FPU in raw-mode VMs
• GUI: properly restore normal/scale mode guest-screen size after exiting full-screen/seamless mode
• GUI: mini-toolbar should provoke less artifacts/conflicts with 3D guest rendering
• GUI: Mac OS X: Native full-screen multi-screen transition was able to blackout host-screens for nearly minute
• GUI: X11: Modern window managers should now use native full-screen multi-screen mapping API
• GUI: added extradata item for configuring the mouse capture behavior, see the manual for more information
• Storage: fixed a VBoxSVC crash when querying an iSCSI target with authentication configured
• Storage: fixed a rare data corruption during reads if another allocating write is running concurrently and accesses the same range
• Storage: fixed a rare crash for certain VHD images from other products
• Storage: fixed a rare release assertion when using the AHCI controller
• Floppy: fixed read errors and guest memory corruption when running under control of QEMM
• 3D: added experimental support for rendering on offline GPUs for Mac OS X host
• 3D: fixed white window appearing on entering FullScreen mode on OSX host
• 3D: fixed video recording support for 3D data regression
• 3D: fixes for MS Office 2013 support
• 3D: several fixes
• Bridged Networking: improved IPv6 support when bridging to a wireless interface
• NAT: prevent internal DNS service from stuck in host-resolver mode when host was switched from one network to another one while host was sleeping
• NAT: preserve DF (if possible) and TOS when proxying outbound UDP datagrams
• NAT: don't let multicast datagrams out
• NAT: fixed handling of large incoming UDP datagrams on Windows hosts
• NAT: fixed handling of the RFC 1533 DHCP PAD option
• NAT Network: fixed inbound half-close on Windows hosts
• NAT Network: preserve IPv4 DF (if possible), TTL, TOS and IPv6 Hop Limit when proxying outbound UDP datagrams
• VRDP: fixed a rare crash when using remote audio input
• USB: fixed several regressions from 4.3.14
• Audio: made the HDA sound emulation work with certain OSX guests (e.g. Mountain Lion)
• Windows hosts: fixed startup problems on certain Windows hosts due to conflicts with anti-virus software
• Windows hosts: fixed 4.3.14 regression whereby AltGr stopped working for some people
• X11 hosts: made the extra key on Brazilian Thinkpads work
• X11 hosts: fixed a problem of input focus cycles and immediately released key presses in full screen mode
• Linux hosts: fixed flooding the kernel log with USB related messages when passing through certain USB devices to a VM
• Linux guests: stop applications crashing when drm_wait_vblank is called
• Linux guests: fix a crash in gnome-session
• X11 guests: do not start VBoxClient over an SSH connection
• X11 guests: added support for X.Org Server 1.16
• X11 guests: fixed a wrong parameter in the video driver which caused problems with full-screen X11 clients
• VirtualKD: introduced stub/loader device for speeding up Windows kernel debugging