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-   -   Would a new forum for Virtual machines and Dual booting be good? (http://www.linuxquestions.org/questions/linux-software-2/would-a-new-forum-for-virtual-machines-and-dual-booting-be-good-716045/)

Chris Stegman 04-01-2009 09:41 AM

Would a new forum for Virtual machines and Dual booting be good?
 
First off, this is just a question to understand what people are thinking and not a proposal. Even if you don't understand virtual machines, your input is as just as valuable as those with knowledge of virtual machines. So if you have any thoughts please just post it.

If you are not familiar with Virtual Machines and want some quick info see

http://www.virtualbox.org/wiki/Virtualization
http://en.wikipedia.org/wiki/Full_virtualization
http://www.vmware.com/technology/virtualization.html

In working with linux for the last few months, having used virtual machines to rebuild multiple machines for learning and trying new packages saved me countless times.

For those of us that regularly use virtual machines such as VMware and Virtual Box, we wield them like a knight with a sword. For those who don't use virtual machines, once you do, you will never go back to dual booting or one machine for one OS.

Using Virtual machines is now so common, that it part of the yearly site poll.
Virtualization Product of the Year - VirtualBox (61.10%)

Until about a year or two ago, using a Virtual machine on your computer required knowledge, a performance machine and some money for good Virtual Machine software. Now with the likes of Virtual Box http://www.virtualbox.org/ , more powerful everyday machines and install wizards, it is practical to use them as you would use any everyday software application such as a word processor, browser, or media player.

Having recently joined linuxquestion.org, I am surprised at the number of people who still are trying to dual boot, and feel that they need to consider virtual machines.

As such, would it be beneficial to create a new forum about running multiple OS, since the virtual machines and dual booting are solutions to the same problem of using multiple OS.

If this post belongs in another forum, please repost.

Thanks

mostlyharmless 04-01-2009 11:50 AM

Quote:

Having recently joined linuxquestion.org, I am surprised at the number of people who still are trying to dual boot, and feel that they need to consider virtual machines.
Since VMs are limited by the hardware support their underlying host can give them, there's plenty of reason to continue to dual boot, unfortunately.

pixellany 04-01-2009 12:06 PM

Virtual machines are slower.

Virtual machines can be more confusing---as in: "Am I talking to the VM or the real HW?"

Once you know how, dual-boot is easy.


In re the question:
Forum for dual-boot: No
Forum for VMs: Yes!

Chris Stegman 04-01-2009 12:16 PM

Quote:

Originally Posted by mostlyharmless (Post 3495052)
Since VMs are limited by the hardware support their underlying host can give them, there's plenty of reason to continue to dual boot, unfortunately.

Thanks for the info.

I am trying to better understand what people think about VMs and consider you point valid. Could you give more details?

Thanks

Chris Stegman 04-01-2009 12:19 PM

Quote:

Originally Posted by pixellany (Post 3495077)
Virtual machines are slower.

Virtual machines can be more confusing---as in: "Am I talking to the VM or the real HW?"

Once you know how, dual-boot is easy.


In re the question:
Forum for dual-boot: No
Forum for VMs: Yes!


Thanks.

I do remember when I had that same problem of learning when the VM or the real server had control of the parts of the hardware and am still learning how to get my memory sticks to work every time.

Is it that you use one OS as a primary, and then dual boot into the other when needed?

mostlyharmless 04-01-2009 12:22 PM

Well, let's say I have a USB device that's recognized by WIndows and not by Linux. Running a VM will not see the device either, as the VM will only have access, at best, to the devices that the Linux kernel presents it with. You *might* be able to let the VM have direct access to your hardware, assuming the VM software allows that, but that also would be rather losing some of the advantage of the VM.

Chris Stegman 04-01-2009 12:39 PM

Quote:

Originally Posted by mostlyharmless (Post 3495089)
Well, let's say I have a USB device that's recognized by WIndows and not by Linux. Running a VM will not see the device either, as the VM will only have access, at best, to the devices that the Linux kernel presents it with. You *might* be able to let the VM have direct access to your hardware, assuming the VM software allows that, but that also would be rather losing some of the advantage of the VM.

Thanks.

Is the Linux kernel unable to see the USB device because a driver is missing or doesn't exist, or the device was not present on boot up so it is not seen, or is it another reason I am missing?

As I have only been using Linux regularly for a few months now, this is a problem I would like to better understand.

reptiler 04-01-2009 12:47 PM

For me it's like this:
I have quite a few systems that I give a try in a VM, including an installation of Windows.
Also I have a real installation of Windows, which I boot into like every few month in order to play some games.

So, having used VMs for a lot of different stuff and seeing that virtualization is growing, I support the idea of having a forum for virtualization.
VMs are not capable to do everything you can do in a "real" system yet.
Games are an example, and I think until this is solved it will still be a while.
Other stuff, like using regular applications, surfing the web, ... (stuff that doesn't require tons of graphics-power ;) ) usually work fine in a VM, given that you assign enough resources to the VM.

A forum for dual-booting I think is not necessary though. Problems regarding dual-booting, I guess, usually revolve around how to configure <insert boot-loader of your choice> in order to be able to boot all the installed systems.

Chris Stegman 04-01-2009 12:57 PM

Quote:

Originally Posted by reptiler (Post 3495108)
For me it's like this:
I have quite a few systems that I give a try in a VM, including an installation of Windows.
Also I have a real installation of Windows, which I boot into like every few month in order to play some games.

So, having used VMs for a lot of different stuff and seeing that virtualization is growing, I support the idea of having a forum for virtualization.
VMs are not capable to do everything you can do in a "real" system yet.
Games are an example, and I think until this is solved it will still be a while.
Other stuff, like using regular applications, surfing the web, ... (stuff that doesn't require tons of graphics-power ;) ) usually work fine in a VM, given that you assign enough resources to the VM.

A forum for dual-booting I think is not necessary though. Problems regarding dual-booting, I guess, usually revolve around how to configure <insert boot-loader of your choice> in order to be able to boot all the installed systems.

I agree with you 100% on system intensive games like FPS (First Person Shooter) on VMs, it doesn't work. Yes simpler games like cards and such do work inside of VMs.

Two people have now mentioned that a new forum for Virtual machines are good, and that no new forum is needed for Dual Booting.

mostlyharmless 04-01-2009 01:11 PM

Quote:

Is the Linux kernel unable to see the USB device because a driver is missing or doesn't exist, or the device was not present on boot up so it is not seen, or is it another reason I am missing?
Usually it's

(1) no hardware support (yet) in the kernel, i.e. no driver exists; sometimes one never will for a variety of reasons

(2) unknown

Here's a good current example of a fellow with a winmodem.

http://www.linuxquestions.org/questi...e-12.1-716110/

Hardware support is only part of it, as noted by other posters; there's a massive thread here on "what would you like see ported to linux" you might want to look at. VMs are wonderful, but not a panacea. I don't really have an opinion on a forum for VMs and dual booting, but think, in general, that there's a balance between too much lumping together and too much fragmentation of fora.

Chris Stegman 04-01-2009 01:54 PM

Quote:

Originally Posted by mostlyharmless (Post 3495137)
Usually it's

(1) no hardware support (yet) in the kernel, i.e. no driver exists; sometimes one never will for a variety of reasons

(2) unknown

Here's a good current example of a fellow with a winmodem.

http://www.linuxquestions.org/questi...e-12.1-716110/

Hardware support is only part of it, as noted by other posters; there's a massive thread here on "what would you like see ported to linux" you might want to look at. VMs are wonderful, but not a panacea. I don't really have an opinion on a forum for VMs and dual booting, but think, in general, that there's a balance between too much lumping together and too much fragmentation of fora.

I think I see my problem. I am taking for granted that the base OS is Windows with a Virtual Machine running a Linux. But what you are referring to is a base OS of Linux with a virtual machine running Windows. Since Linux doesn't have drivers for the hardware, Windows in the VM will never see the device.

Is this correct?

i92guboj 04-01-2009 02:06 PM

Quote:

Originally Posted by Chris Stegman (Post 3495177)
I think I see my problem. I am taking for granted that the base OS is Windows with a Virtual Machine running a Linux. But what you are referring to is a base OS of Linux with a virtual machine running Windows. Since Linux doesn't have drivers for the hardware, Windows in the VM will never see the device.

Is this correct?

It doesn't really matter who's the host and who's the guest. The VM is a "software pc". All the hardware inside the VM is virtual, it doesn't necessarily have a hardware backend. When you reference RAM inside that VM, the VM maps it to whatever virtual memory system the OS can provide at that moment, that might be physical RAM, paging space in disk or a flash drive or whatever else. When you reference a cpu it's not your cpu, but the cpu of the VM, which is a software component of course, and it doesn't have to match your real architecture. In other words, you could be running an x86 virtual cpu on x86_64 hardware or vice versa, or an sparc cpu on x86. It all depends on what architectures your VM can emulate. How that runs on the hardware is completely pointless to the guest OS. The same goes of for all the hardware, including your BIOS and your graphics card, which means that you are going to be accessing a cirrus logic video card or whatever the vm can emulate, and not your shinny geforce 10k25^128 or whatever.

About the VM accessing directly the hardware, it's not that simple. The linux kernel will not let you do that from the userland, that would mean that any program is free to paint a blue screen and hang your machine, to start with, if you get what I mean.

You can only do that via a kernel module that will have to work in sync with the VM.

So, whatever your hardware is, if your host OS can't see it, then the VM can't see it, and hence it can't map it to a virtual device inside the VM. It doesn't matter how many drivers you install inside the VM, the VM has no access to the hardware, only to whatever the host OS can expose. Hence, no driver for linux no access to the device (or in windows by that matter, though it's harder to find products without a windows driver except if you go for mac specific stuff).

lazlow 04-01-2009 02:23 PM

I would say no to both new forums. In both instances a majority of the issues are going to be tied to the host OS or the guest OS. So you would have to split the new forums further into each OS. This will limit the number of people (familiar with that particular OS) that will be exposed to any given post. Keeping things as they are now maximizes each threads exposure.

Chris Stegman 04-01-2009 03:14 PM

Quote:

Originally Posted by i92guboj (Post 3495196)
It doesn't really matter who's the host and who's the guest. The VM is a "software pc". All the hardware inside the VM is virtual, it doesn't necessarily have a hardware backend. When you reference RAM inside that VM, the VM maps it to whatever virtual memory system the OS can provide at that moment, that might be physical RAM, paging space in disk or a flash drive or whatever else. When you reference a cpu it's not your cpu, but the cpu of the VM, which is a software component of course, and it doesn't have to match your real architecture. In other words, you could be running an x86 virtual cpu on x86_64 hardware or vice versa, or an sparc cpu on x86. It all depends on what architectures your VM can emulate. How that runs on the hardware is completely pointless to the guest OS. The same goes of for all the hardware, including your BIOS and your graphics card, which means that you are going to be accessing a cirrus logic video card or whatever the vm can emulate, and not your shinny geforce 10k25^128 or whatever.

About the VM accessing directly the hardware, it's not that simple. The linux kernel will not let you do that from the userland, that would mean that any program is free to paint a blue screen and hang your machine, to start with, if you get what I mean.

You can only do that via a kernel module that will have to work in sync with the VM.

So, whatever your hardware is, if your host OS can't see it, then the VM can't see it, and hence it can't map it to a virtual device inside the VM. It doesn't matter how many drivers you install inside the VM, the VM has no access to the hardware, only to whatever the host OS can expose. Hence, no driver for linux no access to the device (or in windows by that matter, though it's harder to find products without a windows driver except if you go for mac specific stuff).

Can you tell me if there is a flaw with the following.

Given:
Device A has drivers for Windows XP.
Device B has drivers for Windows XP.

Device A does not have drivers for Linux.
Device B does not have drivers for Linux.

Device A has drivers for Virtual Machine's emulated device for Windows XP.
Device B has drivers for Virtual Machine's emulated device for Windows XP.

Device A has drivers for Virtual Machine's emulated device for Linux.
Device B does not have drivers for Virtual Machine's emulated device for Linux.


Configuration 1:
Windows XP is the base OS with virtual machine running Linux.
Drivers for Device A are installed in Windows XP.
Drivers for Device B are installed in Windows XP.
Device A will run for Windows XP.
Device B will run for Windows XP.
Drivers for Device A are installed in Linux.
Drivers for Device B cannot be installed for Linux because they don't exist.
Device A will run for Linux in the virtual machine because it is using Virtual Machine's emulated device.
Device B will not run for Linux in the virtual machine because the drivers do not exist.

Configuration 2:
Linux is the base OS with virtual machine running Windows.
Drivers for Device A are not installed in Linux because they don't exist.
Drivers for Device B are not installed in Linux because they don't exist.
Device A will not run for Linux.
Device B will not run for Linux.
Drivers for device A cannot be installed for Windows XP because there is no emulated device.
Drivers for device B cannot be installed for Windows XP because there is no emulated device.
Device A will not run for Windows XP in the virtual machine because the drivers cannot be installed.
Device B will not run for Windows XP in the virtual machine because the drivers cannot be installed.

Conclusion:
With Configuration 1 you can use Device A and B under Windows XP.
With Configuration 1 you can use Device A but not B under Linux.

With Configuration 2 you can not use Device A and B under Linux.
With Configuration 2 you can not use Device A and B under Windows XP.

pixellany 04-01-2009 03:25 PM

the only flaw is that the analysis is WAY too complicated.....

1. To run any OS on real hardware, you need the appropriate drivers.

2. To run any OS on virtual hardware, you also need the appropriate drivers

Does the guest OS work through the host OS drivers? I don't know, but I also don't care. For example, I am going to have a video driver for both OSes, regardless.

The whole point of virtualization is have the user believe they are dealing with the real hardware. Most people will lack the skills and/or the motivation to dig into the HOW of this.


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