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Re: Larger memory option for VAXstations

On 2015-08-20 23:20, Mouse wrote:
Is there an even more recent VARM out there?  [...]
There was a `second edition' VARM edited in 1990 and released in
1991.  It mostly differs from the first edition by documenting the
vector extension in the new chapters 12 and 13, and an annex B
covering 37 different system models in the B.2 section.

The Revision J one I have describes vector extensions in capters 13 and
14 (chapter 12 documents virtual machines).  It also has an appendix B
"IMPLEMENTATION DEPENDENCIES" which documents 17 different models and
includes a note saying, basically, "we don't have enough people time to
chase down the differences among the models any more; please send us
the info", apparently addressed to other groups within DEC.

It also describes the 21- and 25-bit PFN layouts in chapter 4, but
does not describe which systems use 25-bit PFN and how to enable this
mode on systems which support both flavours.

The document I have makes it sound as though there are no "systems
which support both flavours" - it's written as though the
interpretation of the low 25 bits of a PTE is an intrinsic property of
a particular VAX processor, just as tied to the implementation as (say)
whether MOVTC runs in hardware or takes an instruction-emulation trap.

Well, since the 25-bit PTE changes the interpretation of the PTE, it's something both the hardware and software have to agree on. It's implementation dependent in the way that not all processors will have it, but if they do, the interpretation when in 25-bit mode is not undefined, or implementation dependent.

And yes, there are systems which supports both flavors. Like I said, I have a VAX 7000-720 here, which is running with 1.25 Gig of memory...

$ sho mem
              System Memory Resources on 21-AUG-2015 12:52:31.08

Physical Memory Usage (pages):     Total        Free      In Use    Modified
Main Memory (1280.00Mb) 2621440 2421905 195665 3870

Virtual I/O Cache Usage (pages):   Total        Free      In Use     Maximum
Cache Memory 7310 24 7286 2495981

Slot Usage (slots):                Total        Free    Resident     Swapped
Process Entry Slots 390 364 26 0 Balance Set Slots 351 327 24 0

Dynamic Memory Usage (bytes):      Total        Free      In Use     Largest
Nonpaged Dynamic Memory 10485760 7742272 2743488 7063808 Paged Dynamic Memory 6010880 4632720 1378160 4631024

Paging File Usage (pages):                      Free  Reservable       Total

Of the physical pages in use, 176256 pages are permanently allocated to OpenVMS.
$ show cpu

SIGGE, a VAX 7000-720
Multiprocessing is ENABLED. Streamlined synchronization image loaded.

Active CPUs:      00 01
Configured CPUs:  00 01


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