What is virtual machine? And How to use virtual box?

Virtual environment (Running two operating systems at a time)

1)      Running multiple Operating systems simultaneously
.

2)      Testing and disaster recovery by taking “snapshot”

3)      Host O.S – The physical O.S that is running

4)      Guest O.S – The O.S that is running in  virtual box (Virtual Machine)

5)      Virtual Machine (VM): The environment hat virtual box creates for guest O.S

                                                               i.      It opens like a window

                                                             ii.      It is just like a container

6)      Guest Additions: Specific software packages, adding extra features etc

                                                               i.      Includes shared folders (Host to Guest vice versa), Seamless window, 3D virtualization

7)      Portability: Importing and exporting to other hosts. Works same as like on original host (Importing and exporting in OVF (Open Virtualization Format)

8)      No Hardware virtualization is required, it can work on old and new hardware.

Great Hardware Support:

Guest multiprocessing – 32 virtual cpu’s, USB support, hardware compatibility, Full ACPI support (Advanced configuration and power interface), PXE network boot – integrated virtual network cards of virtual box fully support remote booting via pre boot execution environment.

Multi generation snapshots: Arbitrary snapshots so that you can revert back (Just like system restore)

VM Group: To group virtual machines and to use in another group but the functions take only one signal.

Remote machine display: Virual box remote desktop extension (VRDE) allows for high performance remote access to any running virtual machine. The VRDE doesn’t rely on remote desktop protocol (RDP) of Microsoft, it is build into virtualization layer.

Extensible RDP authentication: Virtual box already supports winlogon on windows (login screen at startup or at screensaver time) and PAM (Pluggable authentication module) on linux.

USB over RDP: Allows you to connect USB devices locally to virtual machine which is running remotely on a virtual box RDP server.

**Virtual box extension packages have “.vbox-expack” file name extensions.

Typing special characters:

1)      Host key + del to send ctrl + alt + del

2)      Host key + backspace to send ctrl + alt + backspace ( to restart graphical user interface of linux of Solaris guest)

3)      Host key + f1 (or other function key) to simulate ctrl + alt + f1 (or other function key ) that is to switch between virtual terminals in linux guest.

Resizing machine’s window:

Scale mode: fits to size of window

Host key + c: enable or disable scale mode

To ignore aspect ratio press shift during resize operaion

Close button on window:

Save machine state: Just like hibernate or suspend mode of laptop

Send the shutdown signal: It sends ACPI (Advanced configuration and power interface ) signal just like shutdown

Power off machine: stops running of VM

Snapshots: Similar to backup

Cloning: Complete backup or linked copy, you can selec “all” to copy all snapshots.

Frontend: 1) Virtual box is a virtual box manager

2) vbox manage is command line interface

3) VboxSDL simple graphical frontend with limited feature set

4) VboxHeadless no visible output on host, acts as RDP if VRDE is installed

Disk image files:

VDI         -              VIRTUAL DISK IMAGE

VMDK   -              FORMAT OF VMWARE

VHD       -              FORMAT USED BY MICROSOFT

HDD       -              PARALLES VERSION 2

/* VMDK AND VHD can be converted

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