[in the begining]

Might have to delve into the History of VM docs for some important related
material.  No doubt the VM spooling system came about as part of the overall
goal of emulating all devices, in this case print and punch.  Prior to the
advent of networked printing solutions (and even now alongside that),
virtual machines printed to a (simulated) channel attached printer.  The
"output" of a virtual printer goes into spool space.

Note that even VMware supports defining a (virtual) parallel port, either
attached to the hosts real parallel port or directed to a file.  To
understand VM spooling, start there and think of it as a place for virtual
print to get stashed.

Mainframes also had the concept of punched cards.  We don't see much these
days of physical punched cards, but the virtual punched cards are going
strong!  Card images become a tremendously handy means of getting stuff from
one virtual machine to another without having to establish other data
sharing.  (Forget the 80 column aspect.  It is just a stream of bytes.)  You
can even boot from a card deck.

[fast forward]

On z/VM, spool space has grown to include much more than store-and-forward
of punched or printed content.  The spooling system on VM is where other
things now reside: dumps (both of VM and of guests), bootable systems (NSS),
shared memory (DCSS), foreign language message repositories, just to name a
few.

Nowadays, "spool space" is the native z/VM hypervisor filesystem.  It is
used for storing anything that might need to survive a reboot but cannot be
stored somewhere else.  (Config disks are CMS formatted.  That is a
different story.)


-- Rick;   <><




On Thu, Sep 25, 2008 at 10:52 AM, Steve Mitchell
<[EMAIL PROTECTED]>wrote:

> Where could a 'newbie' find a comprehensive explanation of Spool?  ie What
> it is intended for, how its used by VM and potentially other
> products/tools/applications.  Thanks.
>
> Steve Mitchell
> Sr Systems Software Specialist
> Blue Cross Blue Shield of Kansas
> (785) 291-8885
>
> 'There are no degrees of Honesty-you're either Honest or you're not!
>
>
>
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