VirtualBox is a general-purpose full virtualizer for x86 hardware. Targeted at server, desktop and embedded use, it is now the only professional-quality virtualization solution that is also Open Source Software.
Modularity. VirtualBox has an extremely modular design with well-defined internal programming interfaces and a client/server design. This makes it easy to control it from several interfaces at once: for example, you can start a virtual machine in a typical virtual machine GUI and then control that machine from the command line, or possibly remotely. VirtualBox also comes with a full Software Development Kit: even though it is Open Source Software, you don't have to hack the source to write a new interface for VirtualBox.
Virtual machine descriptions in XML. The configuration settings of virtual machines are stored entirely in XML and are independent of the local machines. Virtual machine definitions can therefore easily be ported to other computers.
Guest Additions for Windows, Linux and Solaris. VirtualBox has special software that can be installed inside Windows, Linux and Solaris virtual machines to improve performance and make integration much more seamless. Among the features provided by these Guest Additions are mouse pointer integration and arbitrary screen solutions (e.g. by resizing the guest window). There are also guest additions for OS/2 with somewhat reduced functionality.
Shared folders. Like many other virtualization solutions, for easy data exchange between hosts and guests, VirtualBox allows for declaring certain host directories as "shared folders", which can then be accessed from within virtual machines.
- VMM: added support for FSGSBASE, PCID, INVPCID CPU features for guests
- VMM: fixed EMM386 issue with detecting suitable page frame base (bug #10022)
- Front end: Linux: prevent VM window from jumping and auto-resizing to tiny size after resizing it on HiDPI screen
- Front end: Linux: fixed seamless regression caused by wm_class functionality (bugs #12534, #17304)
- Front end: switched to https downloads
- Front end: fixed crash while opening New machine wizard (s.a. forums topic 86592)
- Audio: added support for distinguishing recording sources in the PulseAudio mixer on the host when multiple VMs are running
- Audio: various fixes for the DirectSound backend
- Video recording: added better file seeking support and fixed playback of recorded files with certain players (e.g. Firefox)
- Audio: various fixes for Windows guest surround setups
- Audio: various fixes for HDA emulation
- Serial: fixed an issue where the serial port parameters in the emulation and host serial port got out of sync (bug #17116)
- Storage: fixed overwriting certain INQUIRY data for the DVD/CD drive attached to a AHCI controller
- Storage: fixed handling VMDK images created by Amazon EC2 VM export
- Network: fixed PXE boot regression in e1000
- Network: Added a workaround for older guests which do not enable bus mastering for the virtio PCI device
- 3D: add environment variable to configure presenting 3D content on main thread (see bug #13653)
- Windows hosts: fixed indiscriminate binding of NDIS5 bridged driver, that caused PPPOE malfunction (bugs #16407, #17489)
- Windows guests: fixed incorrect function error when using shared folders in certain applications (bug #14118)
- Linux guests: Linux 4.15 support (bugs #17311, #17320, #17282)
- Linux guests: fixed black screen when 3D enabled in guests (bug #17463, 5.2.6 regression)
- Linux guests: suppress setuid and setgid in shared folders