Introduction to virtual machine software VMware and PC

Virtual machine software can simulate a number of PCs on a computer, each PC can run a separate operating system without interference, you can achieve a computer "at the same time" run several operating systems, but also can connect these operating systems into a network.

For example, the following image is installed on a computer Win2000 server, and then install the virtual machine software vmware on Win2000 server, using VMware to simulate the 3 PCs, on the 3 PCs, respectively, running RedHat7.2, Win98 and the Solaris 8 for x86 operating system. Including Win2000, these 4 operating systems operate on a single computer at the same time, without interference, and in a local area network.

Currently, the virtual machine software on the PC has the following two:

Vmware
Virtual PC for Windows

This article mainly introduces VMware.

Screenshot of Win2000 + VMware run RedHat7.2, Win98 & Solaris 8

Benefits of using virtual machines
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1, if you want to install multiple operating systems on a computer, do not use a virtual machine, there are two ways: one is to install more than one hard disk, each hard disk installed an operating system. This method is more expensive. The second is to install multiple operating systems on a hard drive. This method is not safe enough, because the hard disk MBR is the operating system of the battleground, do not have a few operating systems die together. The use of virtual machine software is both cheap and safe and convenient for friends who want to learn Linux and UNIX.

2. The virtual machine can run several operating systems at the same time on a machine, and it is a necessary tool for SOHO development. With a virtual machine, at home only need a computer, or travel only with a notebook, you can debug C/s, b/a program.

3, the use of virtual machines can be software testing.

Hardware requirements for using virtual machines
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After all, the virtual machine is the task of more than two computers concentrated on a computer, so the hardware requirements are relatively high, mainly CPU, hard disk and memory. The current computer CPU most is PIII above, the hard disk is dozens of G, such configuration already completely can satisfy the request. The key is memory. The need for memory equals the sum of multiple operating system requirements. Now the memory is already very cheap, also not become the problem.

The operating environment of the virtual machine
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VMware can run on Windows (WINNT) and Linux operating systems.

Virtaul PCs can run on Windows (WIN98) and MacOS.

The operating system running the virtual machine software is called the host OS, and the operating system in the virtual machine is called the guest OS.

Experience with VMware
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1, supported guest OS:
VMware supports the following guest OS:
MS-DOS, Win3.1, win9x/me, WinNT, Win2000, WinXP, Win.net, Linux, FreeBSD, NetWare6, Solaris x86.
Unsupported Guest OS:
BeOS, IBM os/2 and Os/2 Warp, Minix, QNX, SCO Unix, UnixWare.

2, VMware Simulation of hardware
VMware's analog hardware includes motherboards, memory, hard disks (IDE and SCSI), Dvd/cd-rom, floppy, NIC, sound card, serial port, and USB port. VMware did not simulate the video card. VMware provides a software package called Vmware-tools for each guest OS to enhance the display and mouse capabilities of the guest OS.

3, VMware Analog hardware is a fixed model, and the actual hardware regardless of the host OS. For example, installing Linux with VMware on a single machine can run the entire Linux copy into other VMware machines without having to install it again.

4, VMware can use the ISO file as a CD. For example, download the Linux ISO file from the Internet, do not need to dial, can be directly installed.

5. VMware provides three options for the operation of the guest OS:
(1) Persistent
Any actions you make in the Guest OS run are saved for immediate filing
(2) undoable
Guest OS shutdown asks if you want to save your actions
(3) Nonpersistend
Any action done in the Guest OS run, after shutdown, is not done.
If you want to carry out software testing or testing, this is a very useful function, you can enjoy playing, the guest OS kill unlimited time are not afraid.

6, VMware's two kinds of network setup mode:
(1) Bridged Way
In this way, the guest OS IP can be set to the same network segment as the host OS, and the guest OS is equivalent to a separate machine within the network, and other machines within the network can access the guest os,guest OS to access other machines in the network, of course, with host Bidirectional access to the OS is also not a problem.

(2) Nat Way
This approach also enables two-way access to the host OS and the guest OS. However, other machines on the network cannot access the Guest os,guest OS to access other machines within the network through the host OS using the NAT protocol.

NAT Way IP Address configuration method: The Guest OS first uses DHCP automatically obtains the IP address, the Host OS's VMware services will assign an IP to the guest OS, then if wants to start each time to use fixed IP words, in guest This IP can be set directly in the OS.

Generally speaking, the bridged way is most convenient and easy to use. However, if the host OS is Win2000 and the network cable is not plugged in, it is likely to be unavailable (most machines with a PCI network card), and this is only Nat.

7, VMware uses the host OS files to simulate the guest OS's hard drive. A guest OS's hard disk corresponds to one or more files in the host OS. If you write 100M files to the guest OS, the virtual hard disk files in the Host OS increase by 100M. Deleting this 100M file in the guest OS will not reduce the virtual hard disk files in the Host OS. The next time you write a file to the guest OS, this part of the space can continue to be used. The Vmware-tools also provides shrink functionality to instantly release unused space, reducing the capacity of the virtual hard disk files in the host OS.
In order to reduce the waste of hard disk space, avoid frequent use of shrink, a better way is to hang another hard disk in the guest OS to store infrequently used files, such as installation files, and then you can repartition the hard disk.

8, Vmware-tools
Vmware-tools enhances the display and mouse function of the guest OS. Vmware-tools with VMware. Install the guest OS, VMware's status bar has a word that vmware-tools not installed, mouse Click this sentence can be installed vmware-tools. can also be installed through the menu: Settings-> VMware Tools Install

If the guest OS is Windows,vmware-tools will automatically install, if it is Linux, after installation, vmware-tools installation files will be mounted to the CD drive (is the virtual mode, the CD drive does not have a CD-ROM), into the CD drive mount point , the file copy out of the installation can be.

VMware does not provide openlinux for some guest OS, such as Solaris x86, NetBSD 1.x, OpenBSD 2.x, and Caldera Vmware-tools 1.3.

9, in VMware installed Linux, do not use graphics mode installation, to be installed in text mode. When you install to the configuration Xserver, you can choose the default configuration, and the installation error will not be ignored. After installation, do not start X, first install a good vmware-tools, then boot x.

10, if not using a sound card, do not add a sound card in VMware, the sound card has a little impact on performance.

11, if the light drive is not often used, you can cancel the optical drive of the Connect at Power on option, when needed, the optical drive can be "hot plug".

The main difference between VMware and virtual PCs
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Virtual PC is a similar VM software to VMware. The main differences between the two are as follows:

1, VMware does not simulate the graphics card, to pass vmware-tools to use high resolution and true color, otherwise only VGA. Virtual PC simulates a more general graphics card: S3 Trio 32/64 (4M). From this point of view, Virtual PCs are more versatile than VMware, but show less performance than VMware.

2, because Virtual PC simulates the graphics card, so versatility is very strong. The connectix.com website claims that the current version of Virtual PC 5 supports all x86 based operating systems.

3, Virtual PC network sharing mode and VMware are different. VMware is the network share through analog NIC, and Virtual PC is by the existing network card binding Virtual PC emulated switch service to achieve network share. For WIN2000/XP and other operating systems, if the network cable is not plugged in or does not have a network card, to install Microsoft's Loopback soft card, to achieve the Internet share. Virtual PC in the global setting, when there is a network card and plug the network cable, the virtual switch set to the reality of the network card; when no network card or network cable is not plugged in, the virtual switch to set into a MS Loopback soft card, can realize network share.
The installation method of MS Loopback soft card, take Win2000 as an example:
Control Panel-> Add/Remove Hardware-> Add/Exclude device failure-> Add new device-> No, select-> network card from list-> manufacturer select Microsoft-> Microsoft Loopback Adapte R.

Win2000 + Virtual pc run Unixware7 screenshot 1

Win2000 + Virtual pc run Unixware7 screenshot 2