Alan Altmark writes:
> On Monday, 01/14/2008 at 06:25 EST, "Bjoern A. Zeeb"
> <[EMAIL PROTECTED]> wrote:
> > > Because a host requires 3 devices (subchannels) to connect to a
> > > HiperSocket, ...
> >
> > Why does it need 3 SCs, as in what is the third for?
>
> It uses one subchannel to receive commands from the host ("write
> control"), one to send command responses and async notifications to the
> host ("read control"), and one or more subchannels to transfer data.
>
> > Is there some (low level) documentation on this?
>
> Other than what you might find in the Linux QDIO device driver source
> code, no, there is no published documentation.
For further reading, I recommend the redbook
"Hipersockets Implementation Guide" (SG24-6816-01)
available in HTML and PDF format at
http://www.redbooks.ibm.com/abstracts/sg246816.html
For a very low level description of how QDIO and iQDIO work for
OSA-Express and Hipersockets, I recommend the paper
"zSeries features for optimized sockets-based messaging:
HiperSockets and OSA-Express" (Baskey et al) in the z900 issue
of the IBM Journal of R&D available in HTML and PDF format at
http://www.research.ibm.com/journal/rd/464/baskey.html
--Malcolm
--
Malcolm Beattie <[EMAIL PROTECTED]>
Linux Technical Consultant
IBM Europe System z
