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I would like to boot the Ubuntu system from the installation DVD, and then make the system, after it started, run no longer from the DVD. It should continue to run using a hard disk or a ram drive, and no longer require access to the boot medium, or the DVD drive.

The purpose is to allow the use of the DVD drive for other tasks in preparation for the Ubuntu installation.

The idea sounds somewhat far-fetched, but I am fairly optimistic that it is possible.

Is there a standard way to do it?
Or are there reasons why it could be impossible?

Possible approaches are:

  • Copying the DVD to a ram drive, and somehow change the directories in / to symbolic links.

  • Find a way to overlay multiple file systems, in a way that the DVD file system continues to exist, but is never accessed again, followed by somehow making the DVD drive no longer depend on the file system.

  • Just remount the root file system somehow?

  • some kind of 'bind' mount?

Volker Siegel
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  • relevant I hope this days https://askubuntu.com/questions/829917/can-i-boot-a-live-usb-fully-to-ram-allowing-me-to-remove-the-disk – nobody Jan 08 '20 at 16:56

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The standard way to run two or more operating systems at the same time is in a virtual machine application. The operating system that runs on the physical machine's bare metal hardware is the host OS. A guest OS is an operating system that runs inside the virtual machine application.

What you're thinking about in your question is that different virtual machine applications have different feature sets that target different scenarios for creating guest OSs.

I don't think you're going to be happy with this explanation unless I illustrate the reverse case where for security reasons applications can run natively inside virtual machines that are elevated to the status of core components of the operating system as is done in Qubes OS. Virtualization is performed by Xen, and user environments can be based on Fedora, Debian, Whonix, and Microsoft Windows, among other operating systems.

karel
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  • The virtual machine would not easily have exclusive access to the DVD drive, right? – Volker Siegel Jan 08 '20 at 16:59
  • If the virtual machine is a core component of the operating system it could be configured to have exclusive access to the DVD drive. – karel Jan 08 '20 at 17:01
  • I am not unhappy about the explanation, the aura of second order inverse abstraction alone is worth reading it! It's right, we could do quite magic stuff on top of a running instance, but it's hard to get between the bare metal and the initial instance. Butt I remember there is a way to migrate a running Linux instance to a different hardware system, while running. I do not know how much instrumentation that needed. – Volker Siegel Jan 08 '20 at 17:30
  • Heterogeneous Live Migration of Virtual Machines In this paper, we propose Vagrant, a live migration framework which bridges the heterogeneity among diverse VMM abstractions and implementations. Vagrant supports the live migration of VMs across heterogeneous VMMs. – karel Jan 08 '20 at 17:37
  • Running a set of virtual machines as core components as in Qubes OS puts an overhead cost on the physical machine's hardware resources. – karel Jan 09 '20 at 02:42