[Info-vax] Intel proposal to simplify x86-64

[Simon Clubley]

On 2023-06-07, Johnny Billquist <bqt at softjar.se> wrote:
>
> Slightly related, I could argue that RSX (and maybe to some extent VMS) 
> are already slightly down the path of microkernels.
>
> In RSX, the file system operations are done in a separate user level 
> process, which is the F11ACP. And networking is done in yet another user 
> level process, the NETACP. Task activation as well as rundown are yet 
> again done by other user level processes (INS and TKTN).
>
> This also means that in theory adding support for new file systems is 
> just a question of writing another ACP and off you go. Unfortunately 
> there are a few places where there are some assumptions in the system, 
> making it not that easy to do absolutely everything in another file 
> system. But for normal file accesses, it works just fine. (In RSX, the 
> problem is that task checkpointing is done outside of the ACP, but to 
> the file system.)
>
> Which is way more separation than you'll find in any kind of Unix like 
> system. But it's not as far as true microkernels go.
>

User mode filesystems are available for a subset of Unix systems however:

https://en.wikipedia.org/wiki/Filesystem_in_Userspace

You can also access some USB devices from user mode as well:

https://libusb.info/

And finally, you can implement network protocols in user mode using
the TUN/TAP device drivers.

But you are right in that none of this is the same as a proper
microkernel however.

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
Walking destinations on a map are further away than they appear.