[Simh] VMS paging

[Villy Madsen]

The issue is not a VMS issue.  The issue is plain and simply a windows XP
issue....

There are a few fragments to be found on Technet that describe very slow opening
of large files...

What I believe is happening is that XP is trying to map all of the virtual disk
into memory - much like VMS can do.  I can see no other reason why XP would
generate essentially a Byte of WRITE io for every byte of space on the virtual
disk..

Now why it doesn't happen as soon as the file is opened by the SIMH console is a
good question - but what is significant is that once it has been opened by the
console, and the massive amount of write IO has been generate, you can do
anything you want, - shut down VMS, detach the drives from VMS,  start up VMS
and re-attach the drives, and the write frenzy will not repeat itself....

However if you detach the files from SimH ......

To re-iterate,  I do not believe that it is an issue with VMS or SimH - I
believe that it is an XP issue that reared it's ugly head in a patch that
occurred sometime early in the fall....


Villy