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

[Dan Cross]

In article <u5r9on$1k1$4 at news.misty.com>,
Johnny Billquist  <bqt at softjar.se> wrote:
>On 2023-06-07 19:58, Simon Clubley wrote:
>> 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.
>
>Fair enough. *These days*, *some* Unix-like systems do allow you to 
>implement parts in user space.
>
>Definitely wasn't the case 30 years ago... :-)

No, Unix 9th Edition was closer to 40 years ago. :-D

	- Dan C.