On Monday, 02/16/2004 at 04:29 CST, Adam Thornton
<[EMAIL PROTECTED]> wrote:
> On Mon, 2004-02-16 at 15:59, Alan Altmark wrote:
> > The linux term "exclusive write" is the same as the VM term
"non-shared
> > copy".  It is NOT the same as a DCSS defined with Exclusive Write (EW)
> > attributes, and it does not prevent access to the existing copy of the
> > DCSS.
>
> OK, I think this is probably the confusing part right here.
>
> So the right methodology is, basically:
>
> do a DEFSEG/SAVESEG from CMS to set the page ranges.
> DEF STOR something-smaller and IPL Linux with mem=something-big.
> modprobe dcssblk and access the segment.
> echo "0" > /proc/dcssblk/segment/shared
> mke2fs the segment, mount it, and put stuff into it
> umount it
> echo "1" > /proc/dcssblk/segment/save
> echo "1" > /proc/dcssblk/segment/shared

I think you have to echo "1" to /save THEN write to the dcss and umount
it.  Something has to "close" the DCSS file in order to cause the
defseg/saveseg.  According to the book the "save" is deferred until close.

Alan Altmark
Sr. Software Engineer
IBM z/VM Development

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