| I asked about this in VMSNOTES a while back; no one could come up with a way to
do it (except, of course, to map the file first). I ended up suggesting it in
VMSPHASE0. (The ability to do stuff like this has other advantages, though
the general case can be VERY complex to implement. At this level, not all
memory is equal - do you want to allow me to take some memory that's part of
a global section and map it to a file, thus getting a copy? That would
require rather different mechanisms than dealing with stuff backed by a
pagefile.)
-- Jerry
|
| Re .0: Gee, that's a bummer that you can't do it. TOPS-20 allows
you to do this WITHOUT zeroing your memory contents. It also
allows you to map a file to pages before putting stuff there.
Of course, there is one bad side effect of mapping pages to a file
after you have done wonderful things to memory - you loose the stuff
in your process space. However, memory does get saved in the file
so all is not lost - you can remap the file to memory.
BTW, one would assume it would be more efficient to map a file to
memory before writing to it. That way, when memory gets modified,
so does the file.
Mike
|