[Info-vax] VSI: "Official 8.4-1H1 Launch"
John Reagan
xyzzy1959 at gmail.com
Mon Jun 8 13:40:30 EDT 2015
On Monday, June 8, 2015 at 1:33:16 PM UTC-4, David Froble wrote:
> Stephen Hoffman wrote:
> > On 2015-06-08 15:07:44 +0000, John Reagan said:
> >
> >> On Monday, June 8, 2015 at 10:51:28 AM UTC-4, Bill Gunshannon wrote:
> >>
> >>> This may come off as a really stupid question, but isn't VMS a
> >>> monolithic kernel? In which case VM and everything else is available
> >>> as soon as the secondary (or tertiary) boot loader loads the kernel
> >>> into memory and jumps there. Right?
> >>
> >> Has not been a monolith since VMS V3 or so.
> >
> > FWIW... When viewed at the file level, OpenVMS is not a monolithic
> > kernel. But in strict computing architecture terms, OpenVMS is a
> > monolithic kernel. VAX/VMS V5.0 brought the modular executive, which
> > means that OpenVMS is a monolithic kernel design with loadable modules.
> > (Unfortunately without much support for unloading kernel code, but I
> > digress.) Once OpenVMS is booted, the kernel is one big wad of code,
> > which is made slightly more tenable through the use of three privileged
> > processor modes. Hybrid and modular kernels tend to use user-space
> > processes, with the closest OpenVMS analog being ACPs. In short,
> > there's no general IPC communications layer used within the OpenVMS
> > kernel, and most OpenVMS kernel stuff is not implemented as ACP-like
> > constructs or UWSS-like constructs. So... OpenVMS is monolithic, with
> > loadable bits.
> >
> > Prior to V5.0, there were parts of the kernel environment that were
> > loaded during the bootstrap, or at run-time. These included device
> > drivers.
> >
> > For those that are curious, the Internals and Data Structures books all
> > have details of the bootstrap and system initialization.
> >
> > Now as for what Bill was asking, OpenVMS initialization involves rather
> > more than loading one whacking great system file.
> >
> >
>
> For sure. For example, even after the VM code is in place, what's it
> going to work with? I don't know the details, but I'd think there has
> got to be tables and such built / initialized so the code knows what
> memory it has to play with. Probably lots of things that need some
> initialization. The OS is code AND data, not just code.
Google ACPI
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