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<chapter>
<title>Plex86 FAQ</title>
<qandaset defaultlabel="qanda">
<qandaentry>
<question>
<para>
What is plex86?
</para>
</question>
<answer>
<para>
Plex86 is an Open Source x86 PC virtualization program which let's you
concurrently run multiple x86 operating systems and corresponding
software on your x86 machine. It is distributed under the GNU LGPL
license.
</para>
</answer>
</qandaentry>
<qandaentry>
<question>
<para>
What is the host OS?
</para>
</question>
<answer>
<para>
The host operating system is the primary OS you run on your real PC
when you boot it.
</para>
</answer>
</qandaentry>
<qandaentry>
<question>
<para>
What is a guest OS?
</para>
</question>
<answer>
<para>
A guest operating system is any OS you run in a virtual machine (VM).
</para>
</answer>
</qandaentry>
<qandaentry>
<question>
<para>
What guest OSes does plex86 run?
</para>
</question>
<answer>
<para>
Look in the file 'GUESTS' in the top level directory of the plex86
source distribution for current info.
</para>
</answer>
</qandaentry>
<qandaentry>
<question>
<para>
What if my guest OS does not run?
</para>
</question>
<answer>
<para>
For now, you will have to wait. We are in a period of architectural
redesign. This is more important than getting more OSes running.
At some pointer after the new architecture is in place, we can
attempt to get more OSes working in plex86.
</para>
</answer>
</qandaentry>
<qandaentry>
<question>
<para>
What kind of technology does plex86 use?
</para>
</question>
<answer>
<para>
Virtualization. In short, plex86 sets up a separate environment for
each virtual machine, including its own page tables and segment
descriptors, such that the guest OS can run natively without interfering
with the host OS. As the guest OS can not drive the same hardware as
the host OS, nor modify system registers use by the host, instructions
which do are trapped and emulated. Therefore, plex86 provides a suite of
hardware emulation for common PC peripheral devices. Virtualization
incorporates native execution and emulation, to provide a complete
Virtual Machine (VM).
</para>
</answer>
</qandaentry>
<qandaentry>
<question>
<para>
Will plex86 run on non-x86 machines?
</para>
</question>
<answer>
<para>
No. Plex86 uses and depends on the native processor, to run most code.
The code is strictly tied to the IA32 x86 architecture. Non x86
architectures are beyond the scope of this project. The subject
has been brought up many times on the developer's list. Please don't
bring it up again.
</para>
</answer>
</qandaentry>
<qandaentry>
<question>
<para>
How does plex86 relate to bochs?
</para>
</question>
<answer>
<para>
Bochs is a portable x86 PC emulation program. It operates completely
in user space, and doesn't make use of native x86 execution. Bochs
is now LGPL, much thanks to MandrakeSoft, makers of the Linux-Mandrake
distribution. Some of the bochs code was borrowed to make plex86.
</para>
</answer>
</qandaentry>
<qandaentry>
<question>
<para>
Will plex86 offer similar capabilities as the commercial VM
product from VMware?
</para>
</question>
<answer>
<para>
One of the goals of plex86 is to provide an efficient VM which
can run multiple OSes on your x86 computer. In this area, plex86
will server similar needs as VMware. But plex86 also has much
potential to be used as a debug environment for OS and driver
developers, because we can export and offer an extensible debug
interface. One that can be modified and enhanced by developers,
since plex86 is Open Source.
</para>
</answer>
</qandaentry>
<qandaentry>
<question>
<para>
What host OSes is plex86 ported to?
</para>
</question>
<answer>
<para>
Only Linux right now.
</para>
</answer>
</qandaentry>
<qandaentry>
<question>
<para>
Who develops plex86?
</para>
</question>
<answer>
<para>
Look in the file 'CONTRIBUTORS' for a list of some of the developers.
</para>
</answer>
</qandaentry>
<qandaentry>
<question>
<para>
What language is plex86 written in.
</para>
</question>
<answer>
<para>
Mostly C. All new code should be written in C. Some user space
plugins are written in C++, because they were shared from bochs.
Do NOT write any new additional code in C++. Many of the same
arguments apply, as to why the Linux kernel is not written in C++.
See the following link for such discussion.
<ulink url="http://www.tux.org/lkml/index.html#s1-4">
http://www.tux.org/lkml/index.html#s1-4
</ulink>
Some components of plex86 user space could conceivably be moved
to monitor space to improve efficiency. Therefore, we need to be
compatible with Linux kernel space, so don't use C++ for this
reason either.
</para>
</answer>
</qandaentry>
</qandaset>
</chapter>
|
