免费小巧虚拟机VirtualBox又发布稳定版更新了，最新版为VirtualBox 4.2.12；再次修复中的大量bug，提升软件性能和稳定性。

VirtualBox 4.2.12的修复内容涉及到GUI、存储、虚拟机管理以及音频多个方面，修复了多屏幕支持方面的大量bug，在虚拟机管理方面则更新了垂直滚动条的特性。

VirtualBox三大特点：免费、小巧、多国语言（含中文）。它最早是德国一家软件公司InnoTek所开发的虚拟系统软件，后来被Sun收购，改名为Sun VirtualBox，在Sun被Oracle收购后现改名为Oracle VirtualBox。

VirtualBox可以在 Linux/Mac 和 Windows 主机中运行， 并支持在其中安装 Windows (NT 4.0、2000、XP、Server 2003、Vista、Win7、Win8)、DOS/Windows 3.x、Linux (2.4 和 2.6)、OpenBSD 等系列的客户操作系统。

VirtualBox 4.2.12的详细更新日志如下：

• 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
• Storage: Fixed incorrect alignment of VDI images causing disk size changes when using snapshots
• Audio: fixed broken ALSA & PulseAudio on some Linux hosts due to invalid symbol resolutionbug #11615)
• PS/2 keyboard: re-apply keyboard repeat delay and rate after a VM was restored from a saved state
• 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
• VBoxManage: don't crash on controlvm guestmemoryballoon if the VM isn't running
• VBoxHeadless: don't filter guest property events as this would affect all clients
• 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
• Linux Additions: handle fall-back to VESA driver on RedHat-based guests if vboxvideo cannot be loaded
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