I thought that the PC term was "seldom-ending channel program." :-) 

Listen to Alan (the advice given would never have come from Chuckie, it was 
right-on)! The directory does not fit the description of being rarely used on 
most systems. Putting it on a volume with page space not only interrupts the 
paging, it slows down access to the directory making logon, link, and directory 
update activity poor performers, too. 

Regards,
Richard Schuh


> -----Original Message-----
> From: VM/ESA and z/VM Discussions [mailto:[EMAIL PROTECTED]
> Behalf Of Alan Altmark
> Sent: Monday, November 07, 2005 10:12 AM
> To: [email protected]
> Subject: Re: Anomaly in the default paging and spooling setup 
> in zVM 5.1
> 
> 
> 
> Eeeeewwwwww!  In general, volumes should be dedicated to 
> paging, not mixed 
> with other data.  If you must share the volume, ensure the 
> other data is 
> rarely, if ever, accessed.
> 
> CP starts a never-ending channel program on the paging volume 
> to handle 
> paging.  If something else needs to be read or written, then 
> the channel 
> program is stopped, the other I/O is performed, and then the channel 
> program is re-started.  If you're doing a lot of paging, 
> that's going to 
> hurt.
> 
> Alan Altmark
> z/VM Development
> IBM Endicott
> 

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