Virtual Box and the Windows Protected O/S

[go_er00@yahoo.com]

Dear Sir:

I am considering installing Virtual Box but I have a question about the software's functionality.

Before Windows XP, operating systems were not protected, therefore, one was able to input/output data through any exteranal i/o port.

If I install old operating sytems using virtual box, will I be able to I/O in the same manner or will the I be stopped by the host's protected operating system?

[BillG]

Yes. VirtualBox simply provides a platform to allow a virtual machine to be created. The OS you install into the vm will operate in very much the same way as it does on physical hardware.

[socratis]

one was able to input/output data through any external i/o port.

What I/O port would that be? Do you want to access raw hardware (memory regions, registers, etc)?

[go_er00@yahoo.com]

Dear BillG:

Thank you for your reply.

Can you tell me whether you have input and output raw data into and out of ports such as the RS232 or LPT1 while the host O/S was a protected operating system? The ports which can transfer data, signalling circuits, and clock pulses are of concern. I am not interested in the IO from gaming ports (joystick, mouse, etc..)

Have you ever actually programmed the input and output out of these ports, or witnessed someone who did?

Thanks for your prior feedback.

[go_er00@yahoo.com]

Dear Socratis;

I appreciate your reply. With regard to answering your question:

What I/O port would that be?

Answer: I am interested in inputting and outputting data and clock pulses from the RS232 or LPT1 ports while the host is Windows 7 or greater O/S.

Can you tell me if this has been accomplished by anyone?

With regard to this question:

Do you want to access raw hardware (memory regions, registers, etc)?

The answer is yes, I want to access registers and memory regions. Before the protected O/S, the old O/Ss could directly affect the kernel. Can Virtual Box be configured with an old O/S as the guest, and IO to ports that are typically under the control of the protected host O/S?

[BillG]

By default the OS in the vm does not see the physical hardware at all. It is virtual machine and its OS sees only its own virtual (emulated) devices. The vm OS will only have access to physical devices indirectly, and then only if VirtualBox passes the data through from the physical device to the virtual device. This will happen at a very low level in the host OS. I doubt that user restrictions imposed by the host OS will have a lot of influence on what can be done by the guest OS.

[go_er00@yahoo.com]

With regard to this quote by BillG:

"if VirtualBox passes the data through from the physical device to the virtual device.."

Has anyone out here attemped to pass data from a physical device to the virtual device?

[mpack]

Has anyone out here attemped to pass data from a physical device to the virtual device?

You can only do that by changing the software.

The premise of your question is fundamentally mistaken. VirtualBox implements a simulation of a computer - A.K.A. a virtual machine. The only "hardware" registers accessible to software running inside the simulation - are simulated registers.

[go_er00@yahoo.com]

I am not an O/S programmer. If Virtual Box can't IO why do programmer's use this software? Is it just so they can write programs that they think will work across many platforms?

[socratis]

That would be a reason. Others include learning, experimenting, having fun, testing.

You want to access the bare metal. You have to do it in the actual hardware, not a virtual one.

[mpack]

That would be a reason. Others include learning, experimenting, having fun, testing.

... and compatibility, i.e. the ability to run applications that require an OS other than the host OS. For Linux and Mac owners I assume the main reason for having a VM is to run Windows apps. For Windows host owners I'd guess it's mostly to use for testing, secure sandbox, disposable computing etc. Of course Mac/Linux owners do that as well.

Basically, suppose you had an infinite amount of cash and office space so you could afford to buy new computers at a whim in order to do this or that: whatever you like really. Clone them if they're important, discard them if they go wrong or the application is no longer needed. VMs make that possible for mere mortals, and without the implied waste.

[go_er00@yahoo.com]

Thank you all for your replies. I got my answer. Virtual Box is for O/S compatibility testing and software development. Thanks again.