[eviks]

Because it's not limited to games, forcing updates cuts of a lot of apps that can't invest enough in updating.

Also the barrier to use you're suggesting with alternative install/emulator is pretty high for an average user. It also breaks integration with everything else (e.g., a simple alt-tab will show the VM instead of 2 apps running inside)

Also because a lot of progress is regression, so having an old way to opt out into is nice

[jasomill]

Integration is the biggest thing. While some desktop VM hosts provide various integration bits like file sharing and rootless window support, the experience is rarely seemless.

Drawing a few examples from an old Raymond Chen blog post[1], integrations required for seemless operation include

• Host files must be accessible in guest applications using host paths and vice versa. Obviously this can't apply to all files, but users will at least expect their document files to be accessible, including documents located on (possibly drive-letter-mapped) network shares.

• Cut-and-paste and drag-and-drop need to work between host and guest applications.

• Taskbar notification icons created by guest applications must appear on the host's taskbar.

• Keyboard layout changes must be synchronized between host and guest.

These are, at least to a useful degree, possible. Integrations that are effectively impossible in the general case:

• Using local IPC mechanisms between host and guest applications. Chen's examples are OLE, DDE, and SendMessage, but this extends to other mechanisms like named pipes, TCP/IP via the loopback adapter, and shared memory.

• Using plug-ins running in the guest OS in host applications and vice versa. At best, these could be implemented through some sort of shim mechanism on a case-by-case basis, assuming the plug-in mechanism isn't too heavily sandboxed, and that the shim mechanism doesn't introduce unacceptable overhead (e.g., latency in real-time A/V applications).

Finally, implementing these integrations without complicated (to implement and configure) safeguards would effectively eliminate most of the security benefits of virtualization.

[1] https://web.archive.org/web/20051223213509/http://blogs.msdn...

[timcobb]

> forcing updates cuts of a lot of apps that can't invest enough in updating.

What about emulation?

[eviks]

emulation is addressed in the next sentence? Also see the sibling comment with more details on the list of issues if you "simulate" the OS instead of using the real one

[timcobb]

It wasn't before, when I asked. Yes now there is more here about emulation :).