VirtualBox是一款免費且開源的虛擬化軟體，允許用戶在電腦上創建和運行虛擬機器。使用VirtualBox，用戶可以在不需要創建單獨的分區或購買額外硬體的情況下，在電腦上同時安裝和運行多個操作系統。

VirtualBox 的主要優勢之一是其易於使用。即使是對虛擬化技術幾乎沒有經驗的人，也可以輕鬆安裝和設置。VirtualBox 還提供廣泛的自定義選項，包括調整分配給每個虛擬機的 RAM、CPU 核心和硬碟空間的能力。

VirtualBox的另一個優點是其與多種作業系統的兼容性。使用者可以在其虛擬機器上安裝和運行Windows、Linux、macOS以及其他許多作業系統。這使得它成為開發人員、軟體測試人員以及需要在單一電腦上運行多個作業系統的人的絕佳工具。

VirtualBox 也提供了一系列的進階功能，如對 USB 設備、共享資料夾和網路配接器的支持。這些功能使得運行需要硬體或網路資源的軟體成為可能，如虛擬路由器、防火牆和伺服器。

VirtualBox 是需要在單一電腦上運行多個作業系統的人的極佳選擇。其易用性、多樣化的自訂選項以及與許多不同作業系統的相容性，使其成為開發人員、IT 專業人士和家庭用戶皆適用的多功能且強大的工具。

關鍵特性：

• 跨平台相容性。
• 直觀的圖形用戶介面。
• 支援各種作業系統。
• 與主機作業系統無縫整合。
• 快照和克隆。
• 網路功能。
• 虛擬設備支援。
• 擴充套件以增加功能。

VirtualBox 4.2.12 (release 2013-04-12)

This is a maintenance release. The following items were fixed and/or added:

• VMM: fixed a Guru Meditation on putting Linux guest CPU online if nested paging is disabled
• VMM: invalidate TLB entries even for non-present pages
• GUI: Multi-screen support: fixed a crash on visual-mode change
• GUI: Multi-screen support: disabled guest-screens should now remain disabled on visual-mode change
• GUI: Multi-screen support: handle host/guest screen plugging/unplugging in different visual-modes
• GUI: Multi-screen support: seamless mode: fixed a bug when empty seamless screens were represented by fullscreen windows
• GUI: Multi-screen support: each machine window in multi-screen configuration should have correct menu-bar now (Mac OS X hosts)
• GUI: Multi-screen support: machine window View menu should have correct content in seamless/fullscreen mode now (Mac OS X hosts)
• GUI: VM manager: vertical scroll-bars should be now updated on content/window resize
• GUI: VM settings: fixed crash on machine state-change event
• GUI: don't show warnings about enabled or disabled mouse integration if the VM was restored from a saved state
• Virtio-net: properly announce that the guest has to handle partial TCP checksums (bug #9380)
• Storage: Fixed incorrect alignment of VDI images causing disk size changes when using snapshots (bug #11597)
• Audio: fixed broken ALSA & PulseAudio on some Linux hosts due to invalid symbol resolution (bug #11615)
• PS/2 keyboard: re-apply keyboard repeat delay and rate after a VM was restored from a saved state (bug #10933)
• BIOS: updated DMI processor information table (type 4): corrected L1 & L2 cache table handles
• Timekeeping: fix several issues which can lead to incorrect time, Solaris guests sporadically showed time going briefly back to Jan 1 1970
• Main/Metrics: disk metrics are collected properly when software RAID, symbolic links or rootfs are used on Linux hosts
• VBoxManage: don't stay paused after a snapshot was created and the VM was running before
• VBoxManage: introduced controlvm nicpromisc (bug #11423)
• VBoxManage: don't crash on controlvm guestmemoryballoon if the VM isn't running (bug #11639)
• VBoxHeadless: don't filter guest property events as this would affect all clients (bug #11644)
• Guest control: prevent double CR in the output generated by guest commands and do NLS conversion
• Linux hosts / guests: fixed build errors on Linux 3.5 and newer kernels if the CONFIG_UIDGID_STRICT_TYPE_CHECKS config option is enabled (bug #11664)
• Linux Additions: handle fall-back to VESA driver on RedHat-based guests if vboxvideo cannot be loaded
• Linux Additions: RHEL/OEL/CentOS 6.4 compile fix (bug #11586)
• Linux Additions: Debian Linux kernel 3.2.0-4 (3.2.39) compile fix (bug #11634)
• Linux Additions: added auto-logon support for Linux guests using LightDM as the display manager
• Windows Additions: Support for multimonitor. Dynamic enable/disable of secondary virtual monitors. Support for XPDM/WDDM based guests
• X11 Additions: support X.Org Server 1.14 (bug #11609)