[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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