- VMware is program which runs under Linux (or NT) and emulates the hardware of a standard PC to provide one or more virtual machines. Many operating systems can be installed on these virtual machines so that it is possible to run, for example, Windows 95 inside a standard X Window under Linux. It is even possible to run a complete Linux installation (maybe a different version) .
- Since the emulation occurs at a low level and runs standard operating system software, there are no additional problems with software compatibility. When running Windows 95, for example, a Windows licence is required and it is the real, full operating system that is running. The operating system believes that it is running on real hardware and speaking to real devices.
- In general, the performance is very good and many applications appear to run as fast as on a native machine. A few applications may however have special problems - in particular programs which interface closely with devices (parallel storage media or
- A well-configured machine is required for acceptable performance - at least 400MHz with 128Mb RAM. Sufficient space is also required for the disk images of the additional operating systems - typically about 500Mb for Windows 95 with MS Office.
- A normal installation of a Microsoft operating system requires a long manual process to configure the system to the specific hardware of the machine. This means that the same installation can not be used for another machine which usually has different hardware. Since VMware emulates the same set of virtual devices on any machine, a single operating system image can be used.
- It is also possible to configure VMware virtual disks in a read-only mode, so that changes to the filesystem are written to a separate log file, rather than being written back to the disk image. When the virtual machine is shut down, the changes can either be discarded or committed back into the disk image. This allows a single disk image to be used without any fear of it being corrupted. It also allows software to be installed experimentally with the installation only being committed if it is successful.
- VMware allows Linux to be used for most commodity computing, while providing access to another operating system, such as MS Windows, running inside a Linux X Window. The guest operating system would be a full, standard version of MS Windows, allowing documents on the Linux file system to be edited with MS Office applications
:- continue
0 comments:
Post a Comment