[HECnet] two dumb RSX questions

[Johnny Billquist]

On 2014-01-01 14:19, Jerome H. Fine wrote:
>Johnny Billquist wrote:

RSX can boot from virtual devices.
Also, you can load and unload device drivers in RSX, but you don't
normally do that just to bring devices offline or online. That is a
separate operation from loading and unloading device drivers. But yes,
if you want to disconnect devices, buses, CPUs or memory, you can do
that just fine on a running RSX system. And bring them online again
later, if you want to. Any other trick you'd like to do? :-)

While it is extremely unlikely that I will ever run RSX-11, the
above ability surprises me.   Please clarify to make sure that
I understand.   It is my impression that RSX-11 requires
all device drivers to be LOADed at boot time and always
be kept LOADed.   TSX-Plus has this requirement and I
guess I assumed that RSX-11 was similar.

Based on your information, I understand that RSX-11 does
support a device driver UNLOAD and REMOVE commands
(or whatever syntax is used in RSX-11 since I just used the
RT-11 syntax).   So please confirm.

Yes. That is correct. You can load and unload device drivers at runtime. That is actually a very important design feature in RSX.
So your understanding about RSX have been totally wrong.

Device drivers that are currently in use can not be unloaded, however. Which means that the boot device can't be unloaded, for instance.

In M+ the ability is even better, as device driver loading and unloading is not related to devices being online or offline.

Not sure exactly what your distinction between unload and remove is.
In RSX terms, you LOAD and UNLOAD device drivers. In 11M, an implicit online of a device is done when you load it, and offline is done on a device before unloading it. In M+ the offline and online steps are separate commands, which just requires that a device driver is loaded.

Even more fun is M+ is that device drivers do not need to be recompiled if you recompile the kernel. Device drivers are totally independent of the kernel.

Also, file systems are also separate, and handled by something called an ACP, which is a separate task. This means that you can have different types of file systems on different disks.
ACPs hook into device drivers, but device drivers have no clue about ACPs.

In respect of RSTS/E, is this possible as well or does RSTS/E
have the same requirement as TSX-Plus?

I think RSTS/E is less flexible, from what I can remember.

	Johnny