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Plex86 Lives, As Lightweight VM Technology
Kevin P. Lawton writes "Plex86 has been completely overhauled, and simplified to be a user (application) code only Virtual Machine technology. For running user code, many of the heavy weight x86-VM techniques are unnecessary. But the bonus is, Linux can easily be made to run inside the plex86 VM, so that the kernel is actually 'pushed down' to user privilege level. This has been demonstrated on both Linux 2.4 and 2.5 kernels. Thus, Linux can run in a plex86 VM without the need for any heavy virtualization. My goal is to keep the code base trim, tight, auditable and get to usable releases quickly. And to favor those goals over adding unnecessary complexities. The first milestones have just been reached, so it's still early in development. There are email lists available on the main plex86 site."
Kevin Lawton is the article submitter, the author of the program and bochs, and is really well known and highly regarded for his skill at this. Virtualizing a bios and all the devices is about as low level as you can get.
Put identity in the browser.
Yes, but UML uses almost 80% of the processor's MTRR registers as a scratchpad to save state. Therefore, any kernel drivers that require real-time interrupt service (NET, SCSI) have to use cut-through emulation, instead of the much faster native emulation.
The bottom line is UML works fine, and exhibits quite decent responsiveness, until you start trying to push disk and or network I/O.
It's a fundemental flaw of UML. But UML's proponents consider it a necessary evil in the name of portability and lightweight robustness. I'm not sure I disagree with them.
Plex86 is a VM that requires that it be run on an actual x86 chip, it virtualizes the code that is running inside the VM so that the code thinks it's got access to it's own machine when in fact it does not, but is running as a user process in linux.
So you can run Windows inside linux, or linux inside linux. They all have to be for the x86 though. But I don't know how well it works.
Bochs is the emulator that runs code for the x86 on ANY processor, PPC, Sparc, whatever it will compile on. So that you could run Windows on a Sparc or a Mac. Though I don't know if it works THAT well.
You should check that again.
VMware under Windows, loads up several device drivers to bridge/route network traffic between the virtual machines and your local NICs.
And when I installed a demo VMware on my Linux box, it needed a kernel headers to build the vmware kernel modules(don't know what for). So, Vmware also needs modules/device drivers for operation.
Kashif
User mode linux is a linux kernel that runs in userspace
plex86 is an x86 virtualizer that lest you create multiple virtual x86 machines to run whatever you want on them.
This will change once SKAS mode goes into the mainline UML distribution. To quote from the UML website:
:) The SKAS page can be read here.
"In short, the changes cause the UML kernel to run in an entirely different host address space from its processes. This solves the security and honeypot fingerprinting problems by making the UML kernel totally inaccessible to UML processes. Their address spaces are identical to what they would be on the host. This also provides a noticable speedup by eliminating the signal delivery that used to happen for every UML system call."
So, there you have it. It requires a kernel patch, but basically solves all the old UML security issues. I don't believe it's quite ready for primetime, though.
May I point out crazybrowser, which embeds IE in a tabbed, popupblocking, cookie-eating enviroment while maintaining compatability with IE-needing sites? I use it as my secondary browser (with Moz being primary)
On the one hand ... VMWare supports specific OSes, not just any x86 OS. So one wonders how complete their virtualization is.
Wrongo. When we say "VMware supports FreeBSD," we mean that customers can call us and expect us to help with problems running FreeBSD in a VM. "Unsupported" guests that work fine include Plan9, BeOS, Openstep, FreeDOS, and AtheOS. VMware is not just a big dumb hack that happens to work for Linux and Windows.